ACUS01 KWNS 121256
SWODY1
SPC AC 121254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Sun Apr 12 2026

Valid 121300Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
TEXAS...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible today into
evening mainly across parts of Texas and perhaps other nearby parts
of the southern Plains. More isolated severe storms may occur across
portions of the Upper Great Lakes and northern Rockies.

...Texas/Southern Plains...
A rather complex scenario exists early today attributable to several
factors including an MCS that de-intensified/decayed generally near
I-35 in Texas overnight, with residual cloud cover and outflow
impacts. Potentially focused in vicinity of outflow, the passing
mid-level wave and persistent warm/moist advection may support storm persistence and redevelopment/intensification later today across
central Texas into parts of east Texas and possibly Louisiana within
a moderately unstable environment.

In the wake of the mid-level wave, mid-level height rises/subsidence
are otherwise anticipated coincident with the dryline from central
Kansas south-southwestward across western Oklahoma and
west/southwest Texas. The extent and likelihood of storm development
later today is highly uncertain, but if/where storms do form, the
environment would generally be supportive of supercells and related
hazards given ample buoyancy and moderate deep-layer shear.

...Minnesota/Wisconsin...
A surface low over the northern Plains will migrate eastward along
the U.S./Canadian border through the day, reaching northern
Minnesota by around peak heating. A narrow tongue of returning
moisture may support a corridor of sufficient ascent and buoyancy
for deep convection. A few surface-based supercells could occur
along the frontal zone where dewpoints may reach into the mid/upper
50s F. While this potential appears low/uncertain per latest
guidance, some tornado threat could materialize along the front.
Hail/wind will otherwise be possible regionally on an isolated
basis.

...Northern Rockies...
Ahead of an approaching upper wave, mid-level moisture will support
another day of fairly modest surface-based buoyancy with persistent
30-40 knot flow within the CAPE-bearing layer. Combined with
somewhat deep boundary-layer mixing, this may support strong to
severe downburst winds with the more robust convective cells, mainly
this afternoon through early evening.

..Guyer/Broyles.. 04/12/2026

$$

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ACUS01 KWNS 121630
SWODY1
SPC AC 121629

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sun Apr 12 2026

Valid 121630Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
SOUTHWEST AND CENTRAL TX...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible today into
evening mainly across parts of Texas and perhaps other nearby parts
of the southern Plains. More isolated severe storms may occur across
portions of the Upper Great Lakes and northern Rockies.

...Synopsis...
Recent satellite imagery shows a pair of phased shortwave troughs
over the Plains, one moving through the Dakotas and another moving
through KS/OK. Both of these waves are forecast to continue
northeastward through the day, with the northern wave reaching
northwestern Ontario and the southern wave reaching the Great Lakes
region. This evolution will take these waves east/northeast of the
higher low-level moisture, which will remain in a corridor from the
southern Plains northeastward into the Upper Midwest. Showers and
thunderstorms are anticipated throughout much of this corridor
today, with highest thunderstorm chances across central/east TX and
from the Upper Midwest into the Great Lakes.

Farther west, an upper low is slowly drifting eastward across
northern CA. Guidance suggests this eastward drift will continue
today, with several shortwave troughs rotating quickly through the
base of this system and ejecting across the Great Basin and northern
Rockies. Large-scale ascent and modest mid-level moisture associated
with these waves will combine with cold temperatures aloft and
associated buoyancy to support thunderstorms today from northern CA
across the northern Great Basin and northern Rockies, and into the
northern Plains.

...Southern/Central Plains...
Much of this region will be displaced south and west of any notable
large-scale forcing for ascent. This limited ascent, combined with
the showers and isolated thunderstorms currently ongoing across
central and east TX, complicates the overall forecast today, with
mesoscale factors likely contributing significantly to when and
where storms develop this afternoon and evening. General expectation
is for development along the southern and western periphery on the
ongoing storms (i.e. from southeast/south-central TX into southwest
TX) later this afternoon and this evening. This redevelopment will
be supported by a combination of moist advection, modest heating,
and limited low-level convergence. Moderate to strong buoyancy amid
moderate vertical shear could support supercells if the mode remains
discrete. However, the weakness in the mid-level flow suggests
storms may tend to cluster, a scenario that is supported by most CAM
guidance. Buoyancy and shear are still strong enough to support
rotating updrafts and large hail early in the convective cycle, but
the trends towards a messy convective mode could limit the
persistence and coverage of robust updrafts. Damaging gusts are
possible even with the clustered storm mode, especially given there
is some potential for slightly more organized bowing segments over
time.

Farther west, mid-level height rises/subsidence are anticipated
coincident with the dryline from central Kansas south-southwestward
across western Oklahoma and west/southwest Texas. The environment, characterized by 1500 to 2000 J/kg of MLCAPE and 30 to 40 kt of
westerly deep-layer shear, is conditionally supportive of supercells
capable of all severe hazards. However, the previously mentioned
height rises and subsidence, combined with modest convective
inhibition, are generally expected to preclude thunderstorm
development. Even so, given the conditional risk, Marginal risk
probabilities will be maintained.

...Minnesota/Wisconsin...
Recent surface analysis places a low just west of FAR, with a warm
front extending southwestward across central/southeast MN and
southern WI. This low is forecast to move eastward today, while the
warm front expands northward. A narrow corridor of surface-based
buoyancy could develop from north-central MN into far northwest WI
as dewpoints increase in the upper 50s (perhaps even low 60s).
Thunderstorm initiation appears possible along the cold front within
this corridor, although veered low-level flow and northward/westward displacement of the better forcing casts doubt to whether updrafts
will be maintained. Any storms that do mature within this warm
sector should become supercells capable of all severe hazards,
including large hail and tornadoes. However, low confidence in storm development and maturity precludes higher probabilities with this
outlook.

...Northern Rockies...
Mid-level moisture will support another day of modest surface-based
buoyancy ahead of the shortwave trough mentioned in the synopsis.
Persistent 30-40 knot flow within the CAPE-bearing layer combined
with somewhat deep boundary-layer mixing will support strong to
severe downburst winds with the more robust convective cells, mainly
this afternoon through early evening.

..Mosier/Squitieri.. 04/12/2026

$$

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ACUS01 KWNS 121958
SWODY1
SPC AC 121956

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Sun Apr 12 2026

Valid 122000Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
CENTRAL TEXAS...

...SUMMARY...
Isolated to scattered severe thunderstorms remain possible today
into evening mainly across parts of Texas and perhaps other nearby
parts of the southern Plains. More isolated severe storms may occur
across portions of the Upper Great Lakes and northern Rockies.

...20z Update Central TX...
Filtered diurnal heating in the wake of earlier showers and storms
across much of central TX was supporting moderate destabilization
this afternoon. While mid-level lapse rates are generally poor,
sufficient destabilization should support a gradual uptick in
convective coverage this afternoon and evening. With moderate
deep-layer shear in place, some organization could support a risk
for damaging gusts, hail, and tornado or two.

...MN/WI...
The aforementioned warm front continues to surge north but has
slowed farther south than earlier guidance. Weak to moderate
destabilization along and just south of the boundary will remain
supportive of a conditions supercell risk this afternoon/evening.
Strong shear profiles east of the surface low and near the rapidly
modifying boundary could support a risk for hail and possibly a
tornado. Have shifted severe probabilities southward slightly to
better match the observed frontal positioning. See MCD #390 for the
latest information.

...OK/KS/TX Panhandle...
A conditional risk for a supercell or two remains evident this
afternoon across the dryline in the central and southern Plains.
Ample heating in the wake of an early morning MCS could allow for
isolated storm this afternoon or evening as the dryline is forecast
to mix eastward before eventually retreating. Forecast guidance
continues to show weak subsidence suppressing convective
development, but deepening cumulus evident over the southern TX
Panhandle could support an isolated storm this evening. All severe
hazards would be possible.

...Intermountain West...
Steep mid-level lapse rates beneath the cold core of the upper low
over the West will continue to support scattered high-based storms
this afternoon. With a relatively dry-sub cloud layer, somewhat deep boundary-layer mixing will support strong to
severe downburst winds.

..Lyons.. 04/12/2026

.PREV DISCUSSION... /ISSUED 1129 AM CDT Sun Apr 12 2026/

...Synopsis...
Recent satellite imagery shows a pair of phased shortwave troughs
over the Plains, one moving through the Dakotas and another moving
through KS/OK. Both of these waves are forecast to continue
northeastward through the day, with the northern wave reaching
northwestern Ontario and the southern wave reaching the Great Lakes
region. This evolution will take these waves east/northeast of the
higher low-level moisture, which will remain in a corridor from the
southern Plains northeastward into the Upper Midwest. Showers and
thunderstorms are anticipated throughout much of this corridor
today, with highest thunderstorm chances across central/east TX and
from the Upper Midwest into the Great Lakes.

Farther west, an upper low is slowly drifting eastward across
northern CA. Guidance suggests this eastward drift will continue
today, with several shortwave troughs rotating quickly through the
base of this system and ejecting across the Great Basin and northern
Rockies. Large-scale ascent and modest mid-level moisture associated
with these waves will combine with cold temperatures aloft and
associated buoyancy to support thunderstorms today from northern CA
across the northern Great Basin and northern Rockies, and into the
northern Plains.

...Southern/Central Plains...
Much of this region will be displaced south and west of any notable
large-scale forcing for ascent. This limited ascent, combined with
the showers and isolated thunderstorms currently ongoing across
central and east TX, complicates the overall forecast today, with
mesoscale factors likely contributing significantly to when and
where storms develop this afternoon and evening. General expectation
is for development along the southern and western periphery on the
ongoing storms (i.e. from southeast/south-central TX into southwest
TX) later this afternoon and this evening. This redevelopment will
be supported by a combination of moist advection, modest heating,
and limited low-level convergence. Moderate to strong buoyancy amid
moderate vertical shear could support supercells if the mode remains
discrete. However, the weakness in the mid-level flow suggests
storms may tend to cluster, a scenario that is supported by most CAM
guidance. Buoyancy and shear are still strong enough to support
rotating updrafts and large hail early in the convective cycle, but
the trends towards a messy convective mode could limit the
persistence and coverage of robust updrafts. Damaging gusts are
possible even with the clustered storm mode, especially given there
is some potential for slightly more organized bowing segments over
time.

Farther west, mid-level height rises/subsidence are anticipated
coincident with the dryline from central Kansas south-southwestward
across western Oklahoma and west/southwest Texas. The environment, characterized by 1500 to 2000 J/kg of MLCAPE and 30 to 40 kt of
westerly deep-layer shear, is conditionally supportive of supercells
capable of all severe hazards. However, the previously mentioned
height rises and subsidence, combined with modest convective
inhibition, are generally expected to preclude thunderstorm
development. Even so, given the conditional risk, Marginal risk
probabilities will be maintained.

...Minnesota/Wisconsin...
Recent surface analysis places a low just west of FAR, with a warm
front extending southwestward across central/southeast MN and
southern WI. This low is forecast to move eastward today, while the
warm front expands northward. A narrow corridor of surface-based
buoyancy could develop from north-central MN into far northwest WI
as dewpoints increase in the upper 50s (perhaps even low 60s).
Thunderstorm initiation appears possible along the cold front within
this corridor, although veered low-level flow and northward/westward displacement of the better forcing casts doubt to whether updrafts
will be maintained. Any storms that do mature within this warm
sector should become supercells capable of all severe hazards,
including large hail and tornadoes. However, low confidence in storm development and maturity precludes higher probabilities with this
outlook.

...Northern Rockies...
Mid-level moisture will support another day of modest surface-based
buoyancy ahead of the shortwave trough mentioned in the synopsis.
Persistent 30-40 knot flow within the CAPE-bearing layer combined
with somewhat deep boundary-layer mixing will support strong to
severe downburst winds with the more robust convective cells, mainly
this afternoon through early evening.

$$

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ACUS01 KWNS 130051
SWODY1
SPC AC 130049

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 PM CDT Sun Apr 12 2026

Valid 130100Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF
CENTRAL TEXAS...

...SUMMARY...
Isolated to scattered severe thunderstorms remain possible this
evening across portions of central Texas and perhaps central/western
Oklahoma.

...Synopsis...
Mid-evening surface observations reveal an expansive warm sector
from the TX coast northward into the Plains and upper MS Valley.
Despite a high-quality thermodynamic environment throughout much of
this warm sector, a combination of residual capping across the upper
MS Valley and/or very weak ascent in the wake of an upper-level
disturbance is limiting the overall potential for thunderstorms
outside of the southern Plains. Across the West, convective coverage
is gradually diminishing and will continue to dwindle heading into
the late evening hours as nocturnal cooling begins to increase
inhibition.

...Southern Plains...
The most intense convection currently resides to the west of the
I-35 corridor in central TX where strong to severe thunderstorms
have developed on the western fringe of an expanding cold pool.
MLCAPE values to the west of the cold pool were recently sampled
near 2500 J/kg by the DRT and OUN soundings with around 30-35 knots
of effective bulk shear also noted. This environment is favorable
for organized convection, including splitting supercells with some
potential for large to very large hail. However, close proximity to
the residual cold pool should limit the overall spatial extent of
this threat, and most guidance depicts this activity waning later
tonight in the absence of persistent forcing for ascent.

Further north into western Oklahoma and northwest TX, continued
cumulus development along a diffuse dryline is noted in GOES
imagery. While storm development appears unlikely given the
approaching onset of nocturnal cooling, the downstream environment
remains highly favorable for intense convection per the 00z OUN
RAOB, and recent RRFS solutions hint at the potential for convection
within the next 1-3 hours (though these solutions appear to be
outliers compared to other guidance). Given this signal and the
favorable environment, opted to maintain 5% hail/wind probabilities
to account for this low-probability, but potentially high impact
scenario.

..Moore.. 04/13/2026

$$

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ACUS01 KWNS 130536
SWODY1
SPC AC 130534

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 AM CDT Mon Apr 13 2026

Valid 131200Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MISSISSIPPI RIVER VALLEY...

...SUMMARY...
Severe thunderstorms are likely across the Upper Mississippi Valley
and Great Lakes region with potential for large to very large hail,
damaging wind, and tornadoes. A more conditional and isolated risk
for severe storms is possible across portions of the southern Plains
late this afternoon and evening.

...Synopsis...
Early-morning water-vapor imagery depicts an upper trough with
multiple embedded vorticity maxima over the Great Basin. While the
primary upper wave will remain over the West for today, a leading
impulse is forecast to eject towards the northern Plains and into
the Great Lakes through tonight. At the surface, a weak lee cyclone
over the central High Plains will migrate northeastward in tandem
with the upper impulse, likely reaching the southern MN vicinity by
early evening. As this occurs, a plume of mid-60s dewpoints will
spread north into the upper MS Valley along and south of a warm
front. Scattered thunderstorm development along and north of the
warm front is anticipated by late afternoon as forcing for ascent
gradually increases. Elsewhere, more isolated strong to severe
thunderstorms are possible across portions of TX and OK where deep
mixing along a dryline may result in sustained deep convection.

...Upper MS Valley...
A combination of shortwave ridging and capping at the base of an EML
will limit thunderstorm development through much of the day across
southern MN into central WI. This will allow for continued moisture
return as a warm front lifts into the region with MLCAPE values
forecast to reach 2000-2500 J/kg by around 21 UTC. Thunderstorm
development will become increasingly probable through the 21-00 UTC
period as isentropic ascent strengthens ahead of the approaching
upper disturbance. Lingering inhibition coupled with 45-50 knot
effective bulk shear should promote initially discrete supercells
along or just north of the surface boundary. Hodograph elongation
appears favorable for a large hail threat, possibly as large as 2-3
inches with the more robust cells. Additionally, enhanced low-level
SRH along the frontal zone may result in a corridor of relatively
higher tornado potential if convection can remain rooted along the
boundary.

While the overall environment appears very favorable for intense
convection, east/northeasterly storm motions along or just north of
the warm front will likely promote storm advection towards the cool
side of the boundary and clustering/upscale growth through the
evening. This, combined with capping over the remainder of the warm
sector, limits confidence in a more widespread tornado threat, and
could modulate the potential for significant (2+ inch) hail within a
few hours after convective initiation. Nonetheless, a corridor of
higher hail potential remains evident in latest guidance along and
just north of the warm front where discrete supercells are most
probable. 30% hail probabilities have been shifted to reflect a
southward trend in frontal placement noted in most recent guidance.

...Southern Plains...
A moist and very unstable air mass will remain in place across TX
and OK today with MLCAPE values expected to increase to around 2500
J/kg by late afternoon. Ample diurnal heating/mixing on the western
periphery of the moisture plume will likely result in weak,
high-based convection by mid to late afternoon. Easterly storm
motions may promote downstream intensification as convection
migrates towards richer low-level moisture, but this will be
conditional on convection remaining sustained long enough to realize
the favorable thermodynamic environment. If this can occur,
deep-layer shear values on the order of 40 knots should promote
organized convection - likely in the form of supercells - with an
attendant threat for all hazards, including very large hail. While
both global and CAM ensemble guidance hint at this potential, the
lack of appreciable lifting mechanisms (aside from the dryline circulation/boundary-layer mixing) casts considerable uncertainty on
overall storm coverage.

..Moore/Wendt.. 04/13/2026

$$

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ACUS01 KWNS 131301
SWODY1
SPC AC 131300

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 AM CDT Mon Apr 13 2026

Valid 131300Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
MINNESOTA AND PARTS OF WISCONSIN...

...SUMMARY...
Severe thunderstorms are likely across the Upper Mississippi Valley
and Great Lakes region with potential for large to very large hail,
damaging wind, and tornadoes, mainly late this afternoon into
tonight. A more conditional and isolated risk for severe storms is
possible across portions of the southern Plains late this afternoon
and evening.

...Upper Mississippi Valley/Great Lakes including MN/WI...
Multiple lead mid-level disturbances over the northern High Plains
will progress northeastward today toward the Upper Midwest, with
strengthening winds aloft across this region particularly late today
and tonight. A surface low will tend to deepen/develop
east-northeastward from northeast Nebraska this morning into far
southern Minnesota and Wisconsin by tonight in vicinity of a slow-moving/stalled frontal boundary. Low/middle 60s F surface
dewpoints will advect north-northeastward and become increasingly
prevalent along/south of the aforementioned stationary/warm front
this afternoon. MLCAPE values are forecast to reach 2000-2500 J/kg
by around 21z/4pm CDT.

Thunderstorm development will become increasingly probable through
mid/late afternoon (21-00z) as isentropic ascent strengthens ahead
of the approaching upper disturbance. Lingering inhibition coupled
with 45-50 kt effective bulk shear should promote initially discrete
supercells along or just north of the surface boundary. Hodograph
elongation appears favorable for a large hail threat, possibly as
large as 2-3 inches in diameter with the more robust cells.
Additionally, enhanced low-level SRH along the frontal zone is
expected to result in a corridor of relatively higher tornado
potential for storms that can remain rooted immediately along the
boundary.

While the overall environment appears very favorable for intense convection/supercells, east-northeasterly storm motions along or
just north of the warm front will likely promote clustering/upscale
growth through the evening, with an increasing damaging wind
potential and a continued tornado risk via line-embedded circulation
potential.

...Northern Illinois/northern Indiana and southern Lake Michigan...
There is the potential that a somewhat separate corridor of
severe-weather potential may unfold today, potentially born out of
subtle mid-level wave and early morning convection across northeast
Missouri vicinity and/or development later today. The initially
elevated storms would be on the edge of the
east/northeastward-advecting elevated mixed layer. Steep mid-level
lapse rates and 35+ kt effective shear could support initially
isolated hail potential, but a more organized surface-based severe
risk could manifest if some of the more-aggressive early morning
short-term guidance trends materialize (HRRR/RAP/RRFS).

...Southern Plains including Oklahoma/Texas...
A moist and potentially unstable air mass will persist regionally to
the east of a dryline located around peak heating from east-central
Kansas south-southwestward into west-central Oklahoma and western
north Texas to the Texas Big Bend vicinity. Immediately east of the
dryline, warm-sector dewpoints are expected to generally be in the
middle 60s F, supporting MLCAPE values to 2500-3000 J/kg.

The extent/likelihood of sustained deep convection later today is a
key question. The primary southern-stream trough will be well
upstream over the southwest Desert, with neutral height tendencies
across the southern Plains, although early morning water vapor
imagery and derived wind data suggest that a subtle disturbance over
northern Mexico and the southern Rockies could approach the
dryline/warm sector later today.

Regardless, ample post-dryline mixing and near-dryline
confluence/weak convergence may be sufficient for deep convective
initiation after 21z/4pm CDT, at least an isolated basis. Forecast
mass fields would imply that this is most probable across
central/southwest Oklahoma into the north Texas Big Country, and
perhaps somewhat separately across the Texas Big Bend and Rio Grande
vicinity.

If/where storms develop and mature, deep-layer shear on the order of
40+ kt will support supercells, potentially capable of all hazards
including very large hail. An increased confidence in deep
convective initiation late this afternoon/early evening could
warrant focus Slight Risk delineations in subsequent Day 1 updates.

...Northern High Plains...
Generally isolated severe storms capable of hail/wind will be
possible late this afternoon into evening along/north of the surface
front where modest low-level moisture and vertical shear will be
maximized, in the presence of steep low/mid-level lapse rates.

..Guyer/Broyles.. 04/13/2026

$$

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ACUS01 KWNS 131638
SWODY1
SPC AC 131636

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1136 AM CDT Mon Apr 13 2026

Valid 131630Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN MINNESOTA...FAR NORTHERN IOWA...AND PARTS OF WISCONSIN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN PLAINS...

...SUMMARY...
Severe thunderstorms are likely across the Upper Mississippi Valley
and Great Lakes region with potential for large to very large hail,
damaging wind, and tornadoes, mainly late this afternoon into
tonight. A more isolated risk for severe storms is possible across
portions of the southern Plains late this afternoon and evening.

...Upper Mississippi Valley/Great Lakes including MN/WI/IA...
Multiple lead mid-level disturbances over the northern High Plains
will progress northeastward today toward the Upper Midwest, with
strengthening winds aloft across this region particularly late today
and tonight. A surface low will tend to deepen/develop
east-northeastward from northeast Nebraska into far southern
Minnesota and Wisconsin by tonight in vicinity of a
slow-moving/stalled frontal boundary. Low/middle 60s F surface
dewpoints will advect north-northeastward and become increasingly
prevalent along/south of the aforementioned stationary/warm front
this afternoon. MLCAPE values are forecast to reach 2000-2500 J/kg
by around 21z/4pm CDT.

Thunderstorm development will become increasingly probable through
mid/late afternoon (21-00z) as isentropic ascent strengthens ahead
of the approaching upper disturbance. This should especially be the
case near the primary boundary. However, semi-discrete warm sector supercellular development, across areas such as southern Wisconsin,
cannot be ruled out. Lingering inhibition coupled with 45-50 kt
effective bulk shear should promote initially discrete supercells.
Hodograph elongation appears favorable for a large hail threat,
possibly as large as 2-3 inches in diameter with the more robust
cells. Additionally, enhanced low-level SRH along the frontal zone
is expected to result in a corridor of relatively higher tornado
potential for storms that can remain rooted immediately along the
boundary.

While the overall environment appears very favorable for intense convection/supercells, east-northeasterly storm motions along or
just north of the warm front will likely promote clustering/upscale
growth through the evening, with an increasing damaging wind
potential and a continued tornado risk via line-embedded
circulations.

...Northern Illinois/northern Indiana and southern Lake Michigan...
See Mesoscale Discussion 395 for short-term details. There is the
potential that a somewhat separate corridor of severe-weather
potential today, potentially via a subtle mid-level wave and morning
convection across northeast Missouri/northwest Illinois vicinity
and/or additional development later today. The initially elevated
storms are on the edge of the east/northeastward-advecting elevated
mixed layer. Steep mid-level lapse rates and 35+ kt effective shear
could support initially isolated hail potential, but a more
organized surface-based severe risk could materialize later this
afternoon, although the specific details remain uncertain.

...Southern Plains including Oklahoma/Texas...
Confidence/potential for isolated to widely scattered locally
intense storms later this afternoon has incrementally increased,
although specifics regarding the extent of convective initiation are
still uncertain.

A moist and potentially unstable air mass will persist regionally to
the east of a dryline located around peak heating from east-central
Kansas south-southwestward into west-central Oklahoma and western
north Texas to the Texas Big Bend vicinity. Immediately east of the
dryline, warm-sector dewpoints are expected to generally be in the
middle 60s F, supporting MLCAPE values to 2500-3000 J/kg. A subtle
disturbance over northern Mexico and the southern Rockies could
approach the dryline/warm sector later today.

Regardless, ample post-dryline mixing and near-dryline
confluence/weak convergence should be sufficient for isolated deep
convective initiation after 21z/4pm CDT. Forecast mass fields and
some short-term guidance would imply that this is most probable
across central/southwest Oklahoma into the north Texas Big Country,
and perhaps somewhat separately across the Texas Big Bend and Rio
Grande vicinity.

If/where storms develop and mature, deep-layer shear on the order of
40+ kt will support supercells, potentially capable of all hazards
including very large hail.

...Northern High Plains...
Generally isolated severe storms including a few low-topped
supercells capable of hail/wind are possible late this afternoon
into evening along/north of the surface front. This is where modest
low-level moisture and vertical shear will be maximized, in the
presence of steep low/mid-level lapse rates.

..Guyer/Chalmers.. 04/13/2026

$$

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ACUS01 KWNS 131957
SWODY1
SPC AC 131956

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Mon Apr 13 2026

Valid 132000Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
SOUTHERN MINNESOTA...NORTHERN IOWA...AND CENTRAL WISCONSIN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF TEXAS...OKLAHOMA AND THE CENTRAL GREAT LAKES....

...SUMMARY...
Severe thunderstorms remain likely across the Upper Mississippi
Valley and Great Lakes region with potential for large to very large
hail, damaging wind, and tornadoes, mainly late this afternoon into
tonight. A more isolated risk for severe storms is possible across
portions of the southern Plains late this afternoon and evening.

...20z Update Upper Midwest...
Afternoon visible imagery showed diurnal heating ongoing south of
the stalled front from the eastern SD across southern MN into
central WI. Moderate destabilization should support scattered to
numerous thunderstorms this afternoon and evening. Initially
supercells are likely, given strongly veering wind profiles and
moderate deep-layer flow. All hazards are possible with these
storms. With time, upscale growth into one or more lines or clusters
appears likely as storms spread eastward into the Great Lakes.

Convective development appears likely along the triple point near
the surface low from northeast/eastern NE into southeastern SD.
Supercell wind profiles and moderate buoyancy would support a risk
for large hail and some damaging wind gusts. A tornado or two may
occur as any supercells that develop move eastward into deeper
low-level moisture across northwestern IA and southern MN.

...Southern and Central Plains...
Towering cumulus along a dryline over parts of KS/OK/TX may support
isolated storm development late this afternoon. A conditionally
favorable environment (3000+ j/kg of MLCAPE and 35-40 kt effective
shear) for supercells will support a risk for all hazards. See MCD
#399 for short term information. The primary change for this outlook
was to extend severe probabilities northeastward into eastern KS.
Guidance and observational trends have shown an increased likelihood
of a storm or two this afternoon.

..Lyons.. 04/13/2026

.PREV DISCUSSION... /ISSUED 1136 AM CDT Mon Apr 13 2026/

...Upper Mississippi Valley/Great Lakes including MN/WI/IA...
Multiple lead mid-level disturbances over the northern High Plains
will progress northeastward today toward the Upper Midwest, with
strengthening winds aloft across this region particularly late today
and tonight. A surface low will tend to deepen/develop
east-northeastward from northeast Nebraska into far southern
Minnesota and Wisconsin by tonight in vicinity of a
slow-moving/stalled frontal boundary. Low/middle 60s F surface
dewpoints will advect north-northeastward and become increasingly
prevalent along/south of the aforementioned stationary/warm front
this afternoon. MLCAPE values are forecast to reach 2000-2500 J/kg
by around 21z/4pm CDT.

Thunderstorm development will become increasingly probable through
mid/late afternoon (21-00z) as isentropic ascent strengthens ahead
of the approaching upper disturbance. This should especially be the
case near the primary boundary. However, semi-discrete warm sector supercellular development, across areas such as southern Wisconsin,
cannot be ruled out. Lingering inhibition coupled with 45-50 kt
effective bulk shear should promote initially discrete supercells.
Hodograph elongation appears favorable for a large hail threat,
possibly as large as 2-3 inches in diameter with the more robust
cells. Additionally, enhanced low-level SRH along the frontal zone
is expected to result in a corridor of relatively higher tornado
potential for storms that can remain rooted immediately along the
boundary.

While the overall environment appears very favorable for intense convection/supercells, east-northeasterly storm motions along or
just north of the warm front will likely promote clustering/upscale
growth through the evening, with an increasing damaging wind
potential and a continued tornado risk via line-embedded
circulations.

...Northern Illinois/northern Indiana and southern Lake Michigan...
See Mesoscale Discussion 395 for short-term details. There is the
potential that a somewhat separate corridor of severe-weather
potential today, potentially via a subtle mid-level wave and morning
convection across northeast Missouri/northwest Illinois vicinity
and/or additional development later today. The initially elevated
storms are on the edge of the east/northeastward-advecting elevated
mixed layer. Steep mid-level lapse rates and 35+ kt effective shear
could support initially isolated hail potential, but a more
organized surface-based severe risk could materialize later this
afternoon, although the specific details remain uncertain.

...Southern Plains including Oklahoma/Texas...
Confidence/potential for isolated to widely scattered locally
intense storms later this afternoon has incrementally increased,
although specifics regarding the extent of convective initiation are
still uncertain.

A moist and potentially unstable air mass will persist regionally to
the east of a dryline located around peak heating from east-central
Kansas south-southwestward into west-central Oklahoma and western
north Texas to the Texas Big Bend vicinity. Immediately east of the
dryline, warm-sector dewpoints are expected to generally be in the
middle 60s F, supporting MLCAPE values to 2500-3000 J/kg. A subtle
disturbance over northern Mexico and the southern Rockies could
approach the dryline/warm sector later today.

Regardless, ample post-dryline mixing and near-dryline
confluence/weak convergence should be sufficient for isolated deep
convective initiation after 21z/4pm CDT. Forecast mass fields and
some short-term guidance would imply that this is most probable
across central/southwest Oklahoma into the north Texas Big Country,
and perhaps somewhat separately across the Texas Big Bend and Rio
Grande vicinity.

If/where storms develop and mature, deep-layer shear on the order of
40+ kt will support supercells, potentially capable of all hazards
including very large hail.

...Northern High Plains...
Generally isolated severe storms including a few low-topped
supercells capable of hail/wind are possible late this afternoon
into evening along/north of the surface front. This is where modest
low-level moisture and vertical shear will be maximized, in the
presence of steep low/mid-level lapse rates.

$$

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ACUS01 KWNS 140056
SWODY1
SPC AC 140054

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 PM CDT Mon Apr 13 2026

Valid 140100Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MISSISSIPPI RIVER VALLEY...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS FAR EASTERN
KANSAS AND FAR WESTERN MISSOURI...

...SUMMARY...
Severe thunderstorms will continue across the Upper Mississippi
Valley and Great Lakes region with potential for large to very large
hail, damaging wind, and tornadoes, through the overnight hours. A
more focused risk for severe storms will continue through late
evening across the southern to central Plains.

...Synopsis...
Late-evening surface analysis reveals a slow-moving surface low over
eastern NE with a warm frontal zone draped eastward into southern MN
and central WI. Scattered strong to severe thunderstorms are ongoing
along the frontal zone as of 01 UTC and will likely continue through
much of the overnight hours across the upper MS Valley and the
Midwest. Further south, several attempts at convective initiation
have been noted along a dryline draped from eastern NE southward
into KS, OK, and TX. Although additional attempts at thunderstorm
development are possible over the next few hours, the primary severe
risk will be focused across the Kansas City metro area where a
cluster of supercells has emerged.

....Upper MS Valley/Midwest...
Scattered supercells are ongoing across southern MN and into central
WI along and north of the surface warm front. A tornado and
significant (2+ inch) hail threat will likely persist for the next
couple of hours, but the expectation is for increased storm
clustering and upscale growth through the overnight hours. The
developing MCS will likely spread east/southeast into southern WI
and possibly northern IL prior to 12 UTC Tuesday with an attendant
risk for severe winds.

...Eastern Kansas/western Missouri...
A cluster of supercells has emerged across eastern KS over the past
few hours and will likely continue to spread east into western MO
through late evening. Given very favorable thermodynamic and
kinematics noted in the 00z TOP sounding, this activity will likely
continue to pose a threat for very large hail and tornadoes. 15%
hail and 5% tornado probabilities have been introduced to account
for this localized threat.

...Southern Plains...
GOES imagery over the past few hours has shown several attempts at
convective initiation across OK and TX; however, most of these
attempts have failed due to very meager/localized ascent along the
dryline. While one strong storm is noted across northwest TX, the
potential for new storm development should wane through the evening
given residual inhibition noted in 00z soundings and as nocturnal
cooling begins to diminish the dryline circulation. Because of this,
opted to remove 15% risk probabilities, but maintain some risk
probabilities given the ongoing convection and otherwise very
favorable convective environment.

..Moore.. 04/14/2026

$$

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ACUS01 KWNS 140551
SWODY1
SPC AC 140550

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1250 AM CDT Tue Apr 14 2026

Valid 141200Z - 151200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MIDWEST...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
TO SOUTHERN PLAINS AND PARTS OF THE NORTHEAST...

...SUMMARY...
Severe thunderstorms are expected this afternoon through tonight
from the southern Plains to the Great Lakes. Large to very large
hail, a few tornadoes (some strong), and damaging wind gusts will be
possible, particularly across parts of eastern Iowa, northern
Illinois, and southern Wisconsin. Additional severe storms, mainly
producing strong wind gusts, will be possible across parts of the
Northeast this afternoon.

...Synopsis...
An upper wave is evident in recent water-vapor imagery across the
southern Great Basin. This trough will translate east into the
Plains through today, reaching the Great Lakes region by tonight.
This will support slight deepening of a diffuse surface low analyzed
over the central High Plains as it drifts east towards the lower MO
River Valley. Ahead of the low, an expansive warm sector
(characterized by widespread mid to upper 60s dewpoints) remains in
place from the southern Plains northeastward into the upper MS
Valley region. Strong to severe thunderstorms are expected along a
composite outflow boundary/warm front from eastern IA into southern
WI/northern IL as well as along a dryline draped from eastern KS
into OK and TX. Further east, a mid-level wave associated with
ongoing convection over the Great Lakes will support re-intensification/re-development of strong/severe storms across the
Northeast.

...Midwest...
An outflow boundary emanating from the ongoing MCS across the Great
Lakes will likely be draped across the Midwest early this morning.
This boundary is forecast to drift northward within a southerly flow
regime as an effective warm front ahead of the approaching surface
low and upper wave. Latest guidance generally depicts this boundary
stalling across eastern IA into southern WI by late afternoon when
daytime heating and ascent ahead of the upper wave will erode
inhibition and promote convective initiation along the boundary.

Dewpoints in the mid to upper 60s coupled with steep mid-level lapse
rates (already noted in upstream 00z RAOBs) will support MLCAPE
values near 2500 J/kg by late afternoon. Moderate buoyancy combined
with 45-55 knots of effective bulk shear will be highly favorable
for organized convection. Capping at the base of the EML should
initially limit thunderstorm coverage and favor discrete supercells
along the boundary. In addition to very large hail (possibly up to
2-3 inches in diameter), enhanced low-level SRH along the boundary
may support a corridor of locally higher tornado potential,
including the potential for significant tornadoes. With time,
easterly storm motions along the boundary will promote upscale
growth with an increasing wind threat heading into the late evening
hours.

The primary uncertainty will be the location of the boundary by late
afternoon. 30% hail and 10% tornado probabilities were adjusted to
reflect the most likely placement of the boundary based on a
consensus of guidance; however, exact placement of the boundary will
be conditional on the precise evolution of the morning MCS.
Similarly, how quickly upscale growth occurs after initiation may
modulate the duration of the significant hail/tornado threat.

...Kansas into Oklahoma and Texas...
Modest height falls across the central to southern Plains combined
with weak convergence along the dryline will likely support isolated
to perhaps scattered thunderstorms from eastern KS southward into TX
this afternoon. Consensus among latest HREF/REFS guidance is that
initiation is most probable across northwest TX into central OK -
possibly ahead of a subtle mid-level wave, though in reality the
unfocused nature of the broad-scale ascent suggests that initiation
will be possible anywhere along the dryline where low-level
convergence can be maximized. Regardless, ample buoyancy within the
warm sector (2500-3000 J/kg MLCAPE sampled in evening RAOBs) coupled
with 30-40 knots of effective bulk shear will support supercells
with an attendant threat for large hail (possibly exceeding 2 inches
in diameter). Some tornado threat will likely materialize around and
after 00 UTC as the nocturnal jet strengthens and enlarges low-level hodographs.

...Northeast...
A low-amplitude upper wave associated with an ongoing MCS across the
Great Lakes will migrate eastward towards the Northeast through the
day. Residual convection associated with the MCS may linger through
morning before re-intensifying by early afternoon as daytime heating
supports steepening low-level lapse rates and increasing MLCAPE
values (likely up to the 500-1000 J/kg range). While buoyancy will
likely remain weak, 35-40 knot bulk shear through the CAPE-bearing
layer and focused ascent ahead of a low-amplitude upper wave will
likely support organization of convective bands with an attendant
threat for strong to severe winds.

..Moore/Wendt.. 04/14/2026

$$

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ACUS01 KWNS 141239
SWODY1
SPC AC 141237

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0737 AM CDT Tue Apr 14 2026

Valid 141300Z - 151200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR IOWA INTO
THE SOUTHERN GREAT LAKES AND PORTIONS OF OKLAHOMA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHEAST...

...SUMMARY...
Severe thunderstorms are expected this afternoon through tonight
from the southern Plains into the Midwest. Large to giant hail,
several tornadoes (some strong), and severe gusts will be possible, particularly from Iowa into the southern Great Lakes.

...Midwest...
An MCV near the IL-IN border this morning and southward-moving
outflow are linked to thunderstorms over parts of the eastern Corn
Belt. This outflow boundary will likely stall with the western
portion of the boundary advancing northward within a strengthening
warm conveyor this afternoon. Guidance generally depicts this
boundary stalling across eastern IA into southern WI by late
afternoon when daytime heating and ascent ahead of the upper wave
will erode inhibition and promote convective initiation along the
boundary. A moist airmass upstream over the lower MO Valley will
advect northeast beneath steep 700-500 mb lapse rates (reference the
12 UTC Topeka, KS raob). MLCAPE at or above 2500 J/kg is forecast
by mid-late afternoon from IA into the IA-WI-IL border vicinity.
Initial storms later this afternoon will rapidly become supercells
with all severe hazards possible. Large to giant hail and an
intense tornado will be possible with the more mature/strongest
supercells where SRH is locally maximized near the boundary.
Upscale growth into a severe cluster is forecast to eventually
evolve during the evening aided by a strong southwesterly LLJ into
the southern Great Lakes. If a supercell develops ahead of the
eastward-moving cluster, a tornado threat could develop as the
boundary layer quickly recovers/destabilizes.

...Kansas into Oklahoma and Texas...
Modest height falls across the central to southern Plains combined
with weak convergence along the dryline will likely support
scattered thunderstorms from eastern KS southward into western north
TX this afternoon into the evening. Aligning with earlier thinking,
strong heating and perhaps weak ascent tied to a subtle mid-level
wave, will favor storm development by 20-22z as convective
inhibition erodes. A very unstable airmass characterized by
2500-3000 J/kg MLCAPE and elongated hodographs will strongly favor
supercells. The strength of low-level shear remains unclear during
the early evening, when the tornado risk could maximize.
Nonetheless, increased confidence in widely scattered to scattered
supercells yielding a risk for large to giant hail prompted an
increase in hail and hail-intensity highlights this outlook update.

...Northeast...
A low-amplitude disturbance associated with an ongoing MCS near Lake
Ontario this morning will move east into the Northeast during the
day. Cloud breaks and low-level warm/moist advection will
contribute to a destabilizing airmass by midday. Veering and
strengthening winds with height will support storm organization,
including the potential for supercells. Eventually a band of storms
is forecast to evolve by mid-late afternoon with wind damage being
the primary risk. Have introduced low hail/tornado probabilities to
account for hazards associated with supercells.

..Smith/Dean.. 04/14/2026

$$

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ACUS01 KWNS 141632
SWODY1
SPC AC 141630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Tue Apr 14 2026

Valid 141630Z - 151200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST/SOUTHERN GREAT LAKES AND SOUTHERN/CENTRAL PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHEAST...

...SUMMARY...
Severe thunderstorms are expected this afternoon through tonight
from the southern Plains into the Midwest. Large to giant hail,
several tornadoes (some strong), and swaths of severe/damaging gusts
are all likely, particularly from Iowa into the southern Great
Lakes.

...Synopsis...
An active severe weather day is anticipated for much of the
southern/central Plains into the Midwest/Great Lakes and parts of
the Northeast. The primary upper trough centered over the Four
Corners late this morning will eject east-northeastward towards the southern/central Plains by this evening, while a separate mid-level
shortwave trough over the northern Plains/Upper Midwest will also
move east-northeastward across the Upper Great Lakes into Ontario.
Another convectively enhanced low-amplitude shortwave trough will
also develop eastward across the Lower Great Lakes into the
Northeast.

Recent surface analysis indicates multiple surface lows, with one
over southern Ontario and another over southeast NE/northeast KS. A
seasonably rich/moist low-level airmass exists to the south of a
front extending between these two lows, with surface dewpoints
already in the low to mid 60s across much of the southern/central
Plains to the east of a dryline. Both the dryline in the
southern/central Plains and developing warm front in the
Midwest/southern Great Lakes will likely serve as foci for intense thunderstorms this afternoon and evening, including the potential
for several supercells.

...Midwest/Ohio Valley/Great Lakes...
A complex scenario for severe thunderstorms remains apparent across
the Midwest/OH Valley into the southern Great Lakes today, with
multiple outflow boundaries from earlier convection rendering
greater than usual uncertainty with the southward extent of possible thunderstorm development in IL/IN/OH. In general, continued
low-level warm advection from the central Plains into the Midwest/OH
Valley will support a moistening/destabilizing airmass through the
afternoon as a northern-stream shortwave trough moves eastward
across the Upper Midwest. A surface warm front will extend
northeastward from a weak surface low in IA across southern WI and
Lower MI. It still appears likely that multiple intense supercells
will develop by 20-21Z along/near this boundary in IA/southern
WI/northern IL in a very favorable airmass for significant severe
hail given strong deep-layer shear and the presence of steep
mid-level lapse rates. Low-level shear is expected to gradually
strengthen through the evening in tandem with a modestly increasing south-southwesterly low-level jet.

Any supercells than can remain on the warm/south side of the front
will be capable of producing tornadoes, a few of which could be
strong (EF-2/3). Some consideration was given to including greater
tornado probabilities and a Moderate Risk (level 4 of 5) focused
across southern WI/far northern IL. But, convection may have a
tendency to grow upscale fairly quickly this evening, so confidence
was not high enough for a categorical upgrade at this time.
Regardless, very large to giant hail (potentially up to 3-4 inches
in diameter) will be a threat with sustained supercells, and a swath
of severe/damaging winds appears likely with a convective cluster
spreading eastward across southern Lower MI this evening into
tonight.

A somewhat separate area of severe potential should also exist
farther south across central IL into IN/OH this afternoon and
evening. Greater low-level moisture and related instability are
expected to exist across these areas compared to locations farther
north. While large-scale forcing should remain fairly weak/nebulous
across this region, a remnant outflow boundary may provide a focus
for supercell development across central IL into IN by 20-21Z. Have
expanded the Slight Risk for large hail, damaging winds, and perhaps
a few tornadoes southward across these areas to account for this
still somewhat uncertain potential.

...Southern/Central Plains...
12Z observed soundings from DRT/MAF/FWD/OUN/TOP show the presence of
steep mid-level lapse rates atop rich low-level moisture (generally
14-15 g/kg mean mixing ratios) along/east of the surface dryline.
Southwesterly mid-level flow and modest ascent preceding the upper
trough over the Southwest/southern Rockies will gradually overspread
the warm sector by mid to late afternoon. Moderate to strong
instability (MLCAPE around 2000-3000 J/kg, locally stronger
possible) and 35-45 kt of deep-layer shear will support multiple
intense supercells. Explosive convective initiation across parts of
western OK into south-central/southeast KS is expected by 20-21Z as
lingering MLCIN erodes with filtered daytime heating and as
convective temperatures are breached.

The overall thermodynamic and kinematic environment appears quite
favorable for very large to potentially giant hail (up to 3-4 inches
in diameter) with any supercells that spread east-northeastward
through the afternoon/evening. A gradually strengthening low-level
jet across OK/KS by 00Z will also support a threat for a few
tornadoes, a couple of which could be strong as low-level hodographs
become enlarged. Gradual upscale growth/clustering should occur with
time through the evening, with some risk for severe/damaging winds.
The Enhanced Risk has been expanded a bit northeastward into south-central/southeast KS for a focused severe wind corridor.
Farther south along the length of the dryline in TX, isolated to
scattered supercells may develop this afternoon and evening, with a
risk for mainly large to very large hail and occasional severe
gusts.

...Northeast...
Ongoing convection across southern Ontario and the Lower Great Lakes
will continue to track eastward this afternoon into NY and parts of
New England in tandem with a low-amplitude shortwave trough. Gradual
clearing of low/mid-level clouds has already encouraged surface
temperatures to warm into the 70s along/south of west-east oriented
front. Thunderstorms are expected to gradually increase in coverage
and intensity as weak to locally moderate instability and strong
deep-layer shear support organized updrafts, including the potential
for some supercells initially. The greatest severe risk will
probably be scattered damaging winds given a tendency for convection
to consolidate into one or more clusters. But, an isolated severe
hail threat may exist with any sustained supercell, along with some
chance for a tornado or two near the front where low-level shear
will be locally enhanced.

..Gleason/Chalmers.. 04/14/2026

$$

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ACUS01 KWNS 141938
SWODY1
SPC AC 141936

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0236 PM CDT Tue Apr 14 2026

Valid 142000Z - 151200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST/SOUTHERN GREAT LAKES AND SOUTHERN/CENTRAL PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHEAST...

...SUMMARY...
Severe thunderstorms are expected this afternoon through tonight
from the southern Plains into the Midwest. Large to giant hail,
several tornadoes (some strong), and swaths of severe/damaging gusts
are all likely, particularly from Iowa into the southern Great
Lakes.

...20Z Update...
A complex yet active severe weather day remains in the forecast for
portions of the Midwest-OH Valley into the Southern Plains this
afternoon into early tonight. While several lines were slightly
adjusted to account for the latest guidance consensus, the following substantial changes and/or decisions were made:

1.) 30 percent wind probabilities were expanded southwestward into
southwest and central OK to account for the possibility of more
rapid upscale growth into one or more wind-producing MCSs or linear
segments.

2.) Category 1/Marginal Risk probabilities for severe wind and hail
were expanded west-southwest into NE along a frontal boundary to
account for two possible scenarios. First, an isolated strong storm
may develop within the next few hours along the boundary as a
consequence of strong diurnal heating. Second, late tonight, there
is low potential for gravity-wave associated convection on the
immediate cool side of the frontal boundary, atop a stable boundary
layer.

3.) Confidence is still too low for supercells across the Midwest to
remain discrete for long periods of time, which would warrant a
Categorical Moderate risk upgrade. Nonetheless, should a dominant
supercell become sustained and discrete for at least a few hours,
especially along the warm front over northeast IA into southern WI,
a sustained and intense tornado will be possible.

The rest of the forecast (see below) remains on track.

..Squitieri.. 04/14/2026

.PREV DISCUSSION... /ISSUED 1130 AM CDT Tue Apr 14 2026/

...Synopsis...
An active severe weather day is anticipated for much of the
southern/central Plains into the Midwest/Great Lakes and parts of
the Northeast. The primary upper trough centered over the Four
Corners late this morning will eject east-northeastward towards the southern/central Plains by this evening, while a separate mid-level
shortwave trough over the northern Plains/Upper Midwest will also
move east-northeastward across the Upper Great Lakes into Ontario.
Another convectively enhanced low-amplitude shortwave trough will
also develop eastward across the Lower Great Lakes into the
Northeast.

Recent surface analysis indicates multiple surface lows, with one
over southern Ontario and another over southeast NE/northeast KS. A
seasonably rich/moist low-level airmass exists to the south of a
front extending between these two lows, with surface dewpoints
already in the low to mid 60s across much of the southern/central
Plains to the east of a dryline. Both the dryline in the
southern/central Plains and developing warm front in the
Midwest/southern Great Lakes will likely serve as foci for intense thunderstorms this afternoon and evening, including the potential
for several supercells.

...Midwest/Ohio Valley/Great Lakes...
A complex scenario for severe thunderstorms remains apparent across
the Midwest/OH Valley into the southern Great Lakes today, with
multiple outflow boundaries from earlier convection rendering
greater than usual uncertainty with the southward extent of possible thunderstorm development in IL/IN/OH. In general, continued
low-level warm advection from the central Plains into the Midwest/OH
Valley will support a moistening/destabilizing airmass through the
afternoon as a northern-stream shortwave trough moves eastward
across the Upper Midwest. A surface warm front will extend
northeastward from a weak surface low in IA across southern WI and
Lower MI. It still appears likely that multiple intense supercells
will develop by 20-21Z along/near this boundary in IA/southern
WI/northern IL in a very favorable airmass for significant severe
hail given strong deep-layer shear and the presence of steep
mid-level lapse rates. Low-level shear is expected to gradually
strengthen through the evening in tandem with a modestly increasing south-southwesterly low-level jet.

Any supercells than can remain on the warm/south side of the front
will be capable of producing tornadoes, a few of which could be
strong (EF-2/3). Some consideration was given to including greater
tornado probabilities and a Moderate Risk (level 4 of 5) focused
across southern WI/far northern IL. But, convection may have a
tendency to grow upscale fairly quickly this evening, so confidence
was not high enough for a categorical upgrade at this time.
Regardless, very large to giant hail (potentially up to 3-4 inches
in diameter) will be a threat with sustained supercells, and a swath
of severe/damaging winds appears likely with a convective cluster
spreading eastward across southern Lower MI this evening into
tonight.

A somewhat separate area of severe potential should also exist
farther south across central IL into IN/OH this afternoon and
evening. Greater low-level moisture and related instability are
expected to exist across these areas compared to locations farther
north. While large-scale forcing should remain fairly weak/nebulous
across this region, a remnant outflow boundary may provide a focus
for supercell development across central IL into IN by 20-21Z. Have
expanded the Slight Risk for large hail, damaging winds, and perhaps
a few tornadoes southward across these areas to account for this
still somewhat uncertain potential.

...Southern/Central Plains...
12Z observed soundings from DRT/MAF/FWD/OUN/TOP show the presence of
steep mid-level lapse rates atop rich low-level moisture (generally
14-15 g/kg mean mixing ratios) along/east of the surface dryline.
Southwesterly mid-level flow and modest ascent preceding the upper
trough over the Southwest/southern Rockies will gradually overspread
the warm sector by mid to late afternoon. Moderate to strong
instability (MLCAPE around 2000-3000 J/kg, locally stronger
possible) and 35-45 kt of deep-layer shear will support multiple
intense supercells. Explosive convective initiation across parts of
western OK into south-central/southeast KS is expected by 20-21Z as
lingering MLCIN erodes with filtered daytime heating and as
convective temperatures are breached.

The overall thermodynamic and kinematic environment appears quite
favorable for very large to potentially giant hail (up to 3-4 inches
in diameter) with any supercells that spread east-northeastward
through the afternoon/evening. A gradually strengthening low-level
jet across OK/KS by 00Z will also support a threat for a few
tornadoes, a couple of which could be strong as low-level hodographs
become enlarged. Gradual upscale growth/clustering should occur with
time through the evening, with some risk for severe/damaging winds.
The Enhanced Risk has been expanded a bit northeastward into south-central/southeast KS for a focused severe wind corridor.
Farther south along the length of the dryline in TX, isolated to
scattered supercells may develop this afternoon and evening, with a
risk for mainly large to very large hail and occasional severe
gusts.

...Northeast...
Ongoing convection across southern Ontario and the Lower Great Lakes
will continue to track eastward this afternoon into NY and parts of
New England in tandem with a low-amplitude shortwave trough. Gradual
clearing of low/mid-level clouds has already encouraged surface
temperatures to warm into the 70s along/south of west-east oriented
front. Thunderstorms are expected to gradually increase in coverage
and intensity as weak to locally moderate instability and strong
deep-layer shear support organized updrafts, including the potential
for some supercells initially. The greatest severe risk will
probably be scattered damaging winds given a tendency for convection
to consolidate into one or more clusters. But, an isolated severe
hail threat may exist with any sustained supercell, along with some
chance for a tornado or two near the front where low-level shear
will be locally enhanced.

$$

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ACUS01 KWNS 150056
SWODY1
SPC AC 150054

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 PM CDT Tue Apr 14 2026

Valid 150100Z - 151200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROS PORTIONS
OF THE GREAT LAKES REGION...

...SUMMARY...
Severe thunderstorms are expected through tonight from the southern
Plains into the Midwest. Large hail, several tornadoes (some
strong), and swaths of severe/damaging gusts are all likely,
particularly from eastern Iowa into the southern Great Lakes.

...Synopsis...
Scattered discrete/semi-discrete supercells are ongoing across
eastern Iowa, far northern Illinois, and southern Wisconsin along a
diffuse warm frontal zone stretching eastward from weak surface low
analyzed over eastern NE/western IA. The primary severe risk through
the overnight hours will be associated with this activity as it
spreads southeast through early morning. Further south across the central/southern Plains, poorly organized convection casts
uncertainty in the nocturnal severe threat; however, a favorable
environment will remain in place through Wednesday morning and could
support severe convection.

...Midwest/Great Lakes...
01 UTC regional radar mosaics show semi-discrete supercells ongoing
across far eastern IA, northern IL, and southern WI with the early
stages of upscale growth evident as storms interactions increase.
This trend will continue through the overnight hours as this
activity propagates east/southeast into lower MI and northern IN.
The recent 00z DVN RAOB sampled a convective environment highly
favorable for organized convection, which will maintain the
potential for significant hail and tornadoes in the near term (most
likely through 03 UTC) before a full transition to a linear mode
takes place. Once this transition occurs, severe winds (including
the potential for significant gusts in excess of 75 mph) and
embedded circulations appear probable for areas downstream.

...Southern Iowa into Kansas...
Thunderstorm development along a southward sagging cold front is
anticipated in the coming hours across northeast KS into southern
IA. Regional soundings sampled adequate buoyancy and strong
deep-layer wind shear (around 50 knots) that will likely support
organized convection along the front for a few hours. Storm motions
along the boundary may foster clustering/upscale growth, but a
severe wind, hail, and perhaps tornado threat is expected to
materialize through the night.

...Oklahoma into Texas...
Convective evolution thus far across western OK into northwest TX
has been relatively lackluster given the otherwise buoyant and
strongly sheared environment sampled by the 00z OUN sounding. This
is likely due to expansive convective outflows resulting in
undercutting and clustered storm modes as well as the presence of a
subsidence inversion (also noted in the 00z sounding). It remains
unclear whether or not this activity will be able to re-intensify
through the late evening hours given. However, strengthening flow
fields through 06 UTC may support some degree of improved
organization and a more robust severe threat. This potential is
hinted by recent HRRR solutions, but overall confidence is limited.
Based on these trends, opted to remove the 30% hail/wind
probabilities given low confidence in severe coverage. Further south
into western TX, attempts at sustained convection have been noted
over the past hour along the dryline, but downstream inhibition may
limit overall storm coverage.

..Moore.. 04/15/2026

$$

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ACUS01 KWNS 150554
SWODY1
SPC AC 150553

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Wed Apr 15 2026

Valid 151200Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN PLAINS...MIDWEST...AND INTO THE GREAT LAKES...

...SUMMARY...
Severe thunderstorms posing a risk for large hail, strong wind
gusts, and a couple of tornadoes will be possible across portions of
the southern Plains toward the Great Lakes this afternoon and
evening.

...Synopsis...
A migratory upper-level wave is evident in water-vapor imagery over
northern Mexico. This feature will lift northeastward into the
Plains through the day, resulting in the eastward progression of a
modest surface cyclone from the central High Plains into eastern NE
by late afternoon. A broad, uncapped, and moderately sheared warm
sector will be in place from the southern Plains into the mid-MS
Valley and eastward into the Great Lakes/OH Valley. Strong to severe thunderstorm development appears probable across much of this warm
sector, whether induced by ascent ahead of the primary upper wave or
by localized mesoscale boundaries.

...Iowa and northern Missouri...
Thunderstorm development appears likely by late afternoon from
central IA into northern MO in the vicinity of the surface low.
Stronger mid-level height falls compared to previous days lends
higher confidence in thunderstorm development, and 50-60 knot 500 mb
flow overspreading much of the warm sector will support organized
convection, including the potential for splitting supercells capable
of very large hail and tornadoes across IA and northern MO. A
focused zone of higher tornado potential may emerge roughly along
the I-80 corridor where backed low-level winds along the effective
warm front will locally augment SRH and could support a strong
tornado. HREF/REFS guidance both show the strongest UH signals
across this zone, warranting higher (5%) tornado probabilities.

...Ozarks into Oklahoma and north Texas...
Further south, initially discrete cells are anticipated along the
dryline from southeast KS into OK and north TX by mid-afternoon.
Despite somewhat higher confidence in storm development compared to
previous days, mean flow vectors along the boundary may promote
clustering and upscale growth within a few hours after initiation.
This scenario appears to be reflected in recent HREF/REFS guidance
in the form of numerous, but weak, UH streaks, as well as in
deterministic CAM solutions that depict one or more convective bands
emerging by early evening. Additionally, guidance hints at the
potential for morning convection across parts of OK and the Ozark
Plateau. It remains unclear what influence - if any- this activity
will have on the southern Plains warm sector or if any outflow
boundaries can emerge and focus a higher severe threat along
mesoscale corridors. Given these uncertainties, all severe
probabilities were expanded to account for the fairly wide envelope
of potential outcomes, most of which will likely feature the
potential for severe hail, wind, and tornadoes.

...Great Lakes into New England...
The combination of low to mid-60s dewpoints and the eastward
advection of an EML will support MLCAPE values upwards of 1000-1500
J/kg across much of the Great Lakes region with gradually
diminishing buoyancy with eastward extent towards the New England
coast. Aloft, 40-50 knot westerly mid-level winds will remain in
place within the crest of a modest ridge, establishing a zonal
corridor of a buoyant and moderately sheared environment. It appears
likely that multiple outflow boundaries and/or mid-level
perturbations associated with upstream MCSs across MI, AR, and IA
will likely reside within the warm sector by peak heating.
Thunderstorm development along or in the vicinity of these features
will support multiple corridors of strong to severe convection. This
scenario is depicted by most recent CAMs, which show multiple
convection bands traversing the warm sector through early evening.
However, exactly where these bands will become established (and
where corridors of higher severe potential will emerge) remains
uncertain given variance in recent guidance.

..Moore/Wendt.. 04/15/2026

$$

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ACUS01 KWNS 151247
SWODY1
SPC AC 151246

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Wed Apr 15 2026

Valid 151300Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
PLAINS INTO THE MIDWEST AND SOUTHERN GREAT LAKES...

...SUMMARY...
Severe thunderstorms posing a risk for large hail to very large
hail, severe gusts, and a couple of tornadoes will be possible
across portions of the southern Plains toward the Great Lakes this
afternoon and evening.

...Synopsis...
Water-vapor imagery this morning shows an upper trough from the
eastern Dakotas south-southwestward into the southern Rockies. A
few disturbances will migrate eastward coincident with the trough
with the most notable being over the central High Plains this
morning. The aforementioned disturbance will move east reaching the
mid-upper MS Valley with the trailing southern extent of the wave
moving into the MO Ozarks and OK by daybreak Thursday. A weak
diffuse low will move from northern KS to the southwest Great Lakes
by late tonight. Farther east, an MCV near MO-IL will translate
east and become perhaps a focus for storm activity later this
afternoon across OH-PA. A rather complex forecast is apparent due
in large part to considerable convection and related outflow
permeating the warm sector overnight across much of the Slight-Risk
area.

...Iowa into the mid MS Valley...
In the wake of showers/storms this morning from IA southward into
MO, a moist and weakly capped airmass will destabilize through early
afternoon. The eastward approach of the mid-level disturbance will
likely contribute towards scattered thunderstorms developing 19-21z
from near the weak low eastward along the composite outflow/frontal
zone into IL-WI and southward into MO within a weakly capped warm
sector. Forecast soundings show straight-line hodographs over IA
with sizable CAPE in the hail growth zone. The potential for
splitting supercells appears evident with the stronger storms
capable of very large hail and perhaps some tornado risk across IA
and northern MO.

...Ozarks into Oklahoma and north Texas...
Morning raobs showed steep 700-500 mb lapse rates (7.5-8 deg C/km)
atop a seasonably very moist return-flow airmass. Models generally
show storm development near the dryline by mid afternoon with
initial development becoming supercellular. Large to very large
hail will be possible with the stronger updrafts. Residual outflow
from overnight convection moving into the Ozarks may play a role in
enhancing low-level shear later today. Forecast soundings show
somewhat limited low-level hodographs with a tendency for a
veer-back-veer signature. Additional storms will favor some
clustering and upscale growth with time due in part to the forecast
hodographs. Nonetheless, all hazards will be possible at least
through the early convective life cycle before the possibility for
wind damage and linear structures perhaps evolve during the evening.

...Southern Great Lakes into the Northeast...
The remnants of an overnight squall line are moving east across
NY-PA this morning with a trailing outflow boundary extending
westward into OH and northeast IN. Moist low levels and the
eastward advection of steeper mid-level lapse rates will act to
destabilize the southern Great Lakes into western PA through midday
and into the afternoon. Forcing for ascent and enhancement of flow
associated with the MCV will potentially focus thunderstorms and aid
in their organization potential beginning this afternoon.
Considerable uncertainty remains regarding this scenario and whether
a mesoscale corridor of higher tornado probabilities is needed
(i.e., northeast OH). Will defer to later outlooks to where perhaps
mesoscale corridors of greater wind/hail threat and an isolated risk
for a couple of tornadoes could develop.

..Smith/Dean.. 04/15/2026

$$

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ACUS01 KWNS 151632
SWODY1
SPC AC 151630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Wed Apr 15 2026

Valid 151630Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS INTO THE MIDWEST/OHIO VALLEY AND
SOUTHERN GREAT LAKES...

...SUMMARY...
Severe thunderstorms posing a risk for large to very large hail,
damaging winds, and perhaps a few tornadoes will be possible across
parts of the southern/central Plains into the Midwest/Ohio Valley
and southern Great Lakes this afternoon and evening.

...Synopsis...
Severe potential across the broad warm sector will be complicated by
ongoing thunderstorms/MCVs and associated cloud cover. A neutral to
positively tilted upper trough will eject northeastward across the southern/central Plains today, with a broad zone of enhanced
mid-level southwesterly winds extending over much of TX/OK into the
Midwest/OH Valley and Great Lakes. At the surface, a weak low over
southeast NE late this morning is forecast to develop slowly
northeastward across IA through the afternoon and evening, with a quasi-stationary front extending northeastward from this low towards
southern WI/Lower MI. A dryline extends southward across KS/OK into
west TX. Multiple MCVs related to ongoing/earlier convection are
also noted in recent visible satellite/radar imagery, and these
features may aid additional convective development this afternoon.

...Iowa into Missouri...
Forcing for ascent associated with the ejecting upper trough will
overspread the front draped across IA this afternoon. Ongoing
supercell in western IA and cloudiness near the front late this
morning cast some uncertainty on the degree of destabilization that
will occur this afternoon, and the overall intensity of convection.
Still, expectations are for additional robust thunderstorms to
eventually develop by 19-21Z along/near the front in IA, with steep
mid-level lapse rates noted on the observed 12Z TOP sounding
supporting moderate to locally strong MLCAPE even if
clouds/precipitation hinder daytime heating to some extent. Various
NAM/RAP forecast soundings show elongated/nearly straight hodographs
at mid/upper levels and 50+ kt of deep-layer shear, which will be
favorable for upper-level/anvil venting and hail production with any
supercells that form. Large to very large hail will be a concern
with initially discrete convection. But, some tendency for
clustering and movement north of the surface front casts
considerable uncertainty on the wind/tornado potential. Even so,
some chance for a few tornadoes and scattered damaging winds may
exist along/south of the front across IA into MO with any convection
that can develop east of the dryline.

...Southern Plains into the Ozarks and Mid Mississippi Valley...
A seasonably moist low-level airmass remains in place across the
southern Plains into the Ozarks and mid MS Valley, with observed 12Z
soundings from FWD/OUN/SGF indicating mean mixing ratios ranging
12-13.6 g/kg. However, even with steep mid-level lapse rates noted
across TX/OK, profiles are fairly saturated at mid/upper levels, and
plentiful cloud cover is present in recent visible satellite imagery
across these regions. It still appears likely that surface-based
thunderstorms will develop this afternoon (around 19-21Z) along/east
of the dryline as MLCIN gradually erodes ahead of the ejecting upper
trough. But, overall evolution remains somewhat unclear, with
potential for messy storm modes/interactions fairly early in the
convective life cycle given a large degree of boundary-parallel flow
in low/mid levels. Initial supercells should pose a threat for
mainly large to very large hail (isolated 2+ inches in diameter),
before clustering and an increase in damaging wind potential occurs.
The tornado threat is less clear, as stronger low-level flow will
tend to remain focused farther north into the Midwest. Still,
sufficient low-level shear should exist this afternoon and evening
to support a threat for a few tornadoes with both supercells and
embedded within clusters.

...Midwest/Ohio Valley into Western Pennsylvania...
An MCV evident over eastern IL/western IN will continue to track
eastward into northern IN and eventually OH this afternoon and
evening. Ongoing thunderstorms associated with this MCV have
remained sub-severe through much of the morning. But, gradual
destabilization of the already moist low-level airmass downstream
should support some uptick in convective coverage and intensity
across the OH Valley by mid to late afternoon. Localized enhancement
to the west-southwesterly low-level winds should focus across parts
of northern OH and vicinity, where somewhat greater low-level shear
and tornado potential may exist. Strong deep-layer shear will easily
support organized convection, including the potential for supercells
with a threat for large hail, damaging winds, and perhaps a couple
of tornadoes. Additional thunderstorms may eventually develop
eastward from the mid MS Valley into IL/IN in association with
another MCV. Large hail, damaging winds, and a tornado or two may
also occur with this activity, if it develops.

..Gleason/Squitieri.. 04/15/2026

$$

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ACUS01 KWNS 151957
SWODY1
SPC AC 151955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Wed Apr 15 2026

Valid 152000Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
SOUTHERN/CENTRAL PLAINS INTO THE MIDWEST/OHIO VALLEY AND SOUTHERN
GREAT LAKES...

...SUMMARY...
Severe thunderstorms posing a risk for large to very large hail,
damaging winds, and perhaps a few tornadoes will be possible across
parts of the southern/central Plains into the Midwest/Ohio Valley
and southern Great Lakes this afternoon and evening.

...20Z Update...

...Mid MS Valley through the Ozarks into the Southern Plains...
Recent surface analysis places a low in the NE/IA/MO border
intersection vicinity, with a dry line extending southwestward from
this low through eastern KS, western OK, and northwest TX. As
mentioned in MCD #448, the elevated supercell ongoing across central
IA could begin to interact with an environment more supportive of
surface-based storms. If a transition to surface-based is realized,
an increased potential for damaging gusts and a tornado will exist.
New development is also beginning across central IA, along the
outflow extending southwestward for this supercell. Hail remains the
primary risk across the region, both with the ongoing supercell and
any new development along its outflow.

Increasing thunderstorm coverage is still expected tonight along the
dryline as it shifts eastward, beginning across northwest TX and
central OK now before expanding northward into MO, and potentially southwestward into more of southwest TX later. Large hail remains
the primary threat with this initially more cellular activity. Some
very large hail (i.e. 2"+ in diameter) is possible. Over time,
storm interactions and/or upscale growth is anticipated, with a
trend towards a threat for more damaging gusts. Tornado threat
remains low, largely due weakness in the low to mid-level flow and
convective mode issues. However, some modest strengthening of the
low-level flow should exist this afternoon and evening from eastern
OK into the mid MS Valley, supporting a threat for a few tornadoes
with both supercells and embedded within clusters.

...OH Valley...
Severe Thunderstorm Watch #120 is currently ongoing from far
southeast Lower MI across northern OH into far northwest PA. Here, a
mix of clusters and supercells pose a threat for scattered damaging
winds and large hail as they spread quickly east-northeastward this
afternoon and evening. A tornado or two is also possible.

..Mosier.. 04/15/2026

.PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Apr 15 2026/

...Synopsis...
Severe potential across the broad warm sector will be complicated by
ongoing thunderstorms/MCVs and associated cloud cover. A neutral to
positively tilted upper trough will eject northeastward across the southern/central Plains today, with a broad zone of enhanced
mid-level southwesterly winds extending over much of TX/OK into the
Midwest/OH Valley and Great Lakes. At the surface, a weak low over
southeast NE late this morning is forecast to develop slowly
northeastward across IA through the afternoon and evening, with a quasi-stationary front extending northeastward from this low towards
southern WI/Lower MI. A dryline extends southward across KS/OK into
west TX. Multiple MCVs related to ongoing/earlier convection are
also noted in recent visible satellite/radar imagery, and these
features may aid additional convective development this afternoon.

...Iowa into Missouri...
Forcing for ascent associated with the ejecting upper trough will
overspread the front draped across IA this afternoon. Ongoing
supercell in western IA and cloudiness near the front late this
morning cast some uncertainty on the degree of destabilization that
will occur this afternoon, and the overall intensity of convection.
Still, expectations are for additional robust thunderstorms to
eventually develop by 19-21Z along/near the front in IA, with steep
mid-level lapse rates noted on the observed 12Z TOP sounding
supporting moderate to locally strong MLCAPE even if
clouds/precipitation hinder daytime heating to some extent. Various
NAM/RAP forecast soundings show elongated/nearly straight hodographs
at mid/upper levels and 50+ kt of deep-layer shear, which will be
favorable for upper-level/anvil venting and hail production with any
supercells that form. Large to very large hail will be a concern
with initially discrete convection. But, some tendency for
clustering and movement north of the surface front casts
considerable uncertainty on the wind/tornado potential. Even so,
some chance for a few tornadoes and scattered damaging winds may
exist along/south of the front across IA into MO with any convection
that can develop east of the dryline.

...Southern Plains into the Ozarks and Mid Mississippi Valley...
A seasonably moist low-level airmass remains in place across the
southern Plains into the Ozarks and mid MS Valley, with observed 12Z
soundings from FWD/OUN/SGF indicating mean mixing ratios ranging
12-13.6 g/kg. However, even with steep mid-level lapse rates noted
across TX/OK, profiles are fairly saturated at mid/upper levels, and
plentiful cloud cover is present in recent visible satellite imagery
across these regions. It still appears likely that surface-based
thunderstorms will develop this afternoon (around 19-21Z) along/east
of the dryline as MLCIN gradually erodes ahead of the ejecting upper
trough. But, overall evolution remains somewhat unclear, with
potential for messy storm modes/interactions fairly early in the
convective life cycle given a large degree of boundary-parallel flow
in low/mid levels. Initial supercells should pose a threat for
mainly large to very large hail (isolated 2+ inches in diameter),
before clustering and an increase in damaging wind potential occurs.
The tornado threat is less clear, as stronger low-level flow will
tend to remain focused farther north into the Midwest. Still,
sufficient low-level shear should exist this afternoon and evening
to support a threat for a few tornadoes with both supercells and
embedded within clusters.

...Midwest/Ohio Valley into Western Pennsylvania...
An MCV evident over eastern IL/western IN will continue to track
eastward into northern IN and eventually OH this afternoon and
evening. Ongoing thunderstorms associated with this MCV have
remained sub-severe through much of the morning. But, gradual
destabilization of the already moist low-level airmass downstream
should support some uptick in convective coverage and intensity
across the OH Valley by mid to late afternoon. Localized enhancement
to the west-southwesterly low-level winds should focus across parts
of northern OH and vicinity, where somewhat greater low-level shear
and tornado potential may exist. Strong deep-layer shear will easily
support organized convection, including the potential for supercells
with a threat for large hail, damaging winds, and perhaps a couple
of tornadoes. Additional thunderstorms may eventually develop
eastward from the mid MS Valley into IL/IN in association with
another MCV. Large hail, damaging winds, and a tornado or two may
also occur with this activity, if it develops.

$$

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ACUS01 KWNS 160058
SWODY1
SPC AC 160057

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Wed Apr 15 2026

Valid 160100Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING IN A
CORRIDOR FROM THE SOUTHEASTERN GREAT PLAINS THROUGH THE MIDWEST...

...SUMMARY...
Potential for damaging wind gusts could still increase a bit with
developing clusters of storms through mid to late evening across
parts of the Midwest into the southeastern Great Plains, while also
continuing with another cluster of storms spreading across northern
portions of the Allegheny Plateau.

...01Z Update...
Mid-level ridging centered near the south Atlantic Seaboard remains
prominent, but is undergoing some suppression as at least a couple
of short wave troughs migrate around its western through northern
periphery. The most substantive of these waves is forecast to
continue migrating northeast of the lower Missouri Valley through Wisconsin/Illinois by late tonight, accompanied by a modest
downstream surface frontal wave. A vigorous jet streak associated
with one or two lower amplitude downstream perturbations is forecast
to propagate from the lee of the lower Great Lakes through southern
New England. It appears that mid/upper troughing with embedded
low-amplitude perturbations will linger across parts of the southern
Great Plains.

Peak afternoon destabilization along the dryline, from near its
frontal intersection (roughly near/north of the Greater Kansas City
area) southwestward into the Texas South Plains, is already waning.
However, it appears that at least a narrow corridor of moderate
residual boundary-layer instability in the warm sector to its east
could may maintain vigorous convection and support continuing
upscale convective growth into mid/late evening across parts of
southeastern Oklahoma, western/northern Arkansas, central/eastern
Missouri and central/northern Illinois. As this occurs, largely
coincident with a northeastward propagating 30-40 kt southwesterly
850 mb jet, this may be accompanied by developing areas of
increasing potential for damaging wind gusts and perhaps a few brief
tornadoes, before convection weakens overnight.

..Kerr.. 04/16/2026

$$

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ACUS01 KWNS 160601
SWODY1
SPC AC 160559

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Thu Apr 16 2026

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS PARTS OF WESTERN AND CENTRAL NEW YORK INTO SOUTHERN
VERMONT...

...SUMMARY...
A few severe thunderstorms are possible this afternoon in a corridor
across western through central New York (state) and adjacent
southern Vermont.

...Discussion...
A significant mid-level trough and embedded low now digging across
the Pacific Northwest is forecast to split as it continues inland
through this period. One perturbation, perhaps including a
continuing cyclonic circulation, is forecast to turn eastward across
the northern Rockies through the central Canadian/U.S. border area.
Another perturbation is forecast to dig southeastward across the
Great Basin into early Friday. It appears that the larger-scale
evolving troughing will be preceded by a significant cold frontal
surge to the lee of the northern U.S. Rockies, through much of the
northern and central Great Plains by 12Z Friday.

Downstream, initially prominent mid-level ridging centered near the
southern Atlantic Seaboard is forecast to become increasingly
suppressed, as one short wave trough, approaching southwestern
portions of the Great Lakes region early today, turns eastward then southeastward across the lower Great Lakes vicinity into northern
Mid Atlantic. It appears that this will be trailed by another
perturbation, which is forecast to progress east of the Ozark
Plateau through the lower Ohio and Tennessee Valleys, before digging
across the southern Appalachians, downstream of short wave ridging
building across and east of the mid/upper Mississippi Valley.

...Mid South into lower Great Lakes and Northeast...
The primary and trailing short wave troughs advancing to the east of
the Mississippi Valley are forecast to be preceded by the remnants
of overnight convection across parts of the lower Great Lakes, Ohio
Valley, and Mid South at the outset of the period. The impacts of
associated cloud cover and outflow on destabilization within the
warm sector of a broad, but weak, surface low migrating northeast of
the lower Great Lakes during the day remain unclear. However,
various model output, including convection allowing guidance,
suggest that destabilization and strengthening shear along a warm
frontal zone (as it strengthens with differential heating) may
become a focus for organized strong thunderstorm development across
New York state by afternoon. It appears that this may include an
evolving cluster, perhaps preceded by more discrete thunderstorm
activity, in an environment conducive to evolving supercell
structures, with potential to produce severe hail, wind and a risk
for a couple of tornadoes.

Additional thunderstorm activity may eventually develop and
strengthen, accompanied by at least a risk for strong to severe wind
gusts by late afternoon, in a corridor of stronger daytime heating
ahead of a developing cold front spreading into the upper Ohio
Valley/Allegheny and Cumberland Plateau by late afternoon.

There is not a well-defined signal in the latest model output, but a
corridor of differential surface heating along weakening trailing
convective outflow across the Mid South vicinity could become a
focus for supercell development. It currently appears that this
potential could peak across north central into northeastern Arkansas
by late this afternoon, aided by moderate boundary-layer
destabilization and stronger mid-level forcing for ascent associated
with a cyclonic vorticity center migrating across the region.

...Southern Great Plains...
Moderate to strong potential instability is forecast to develop
beneath steep lapse rates, along and east of a dryline which likely
will be retreating westward across the high plains by early this
evening. While this will be conditionally support of severe
thunderstorm development, forcing to support initiation of sustained thunderstorms remains unclear, associated from, perhaps, the higher
terrain near/east of the Texas Big Bend. Beneath moderate to strong southwesterly mid/upper flow, this could include an isolated
supercell or two which could propagate across the Rio Grande River,
before weakening in the presence of increasing inhibition this
evening.

..Kerr/Lyons.. 04/16/2026

$$

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ACUS01 KWNS 161236
SWODY1
SPC AC 161234

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0734 AM CDT Thu Apr 16 2026

Valid 161300Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NEW YORK INTO
SOUTHERN VERMONT AND OVER THE NORTHERN HALF OF ARKANSAS...

...SUMMARY...
Scattered severe thunderstorms are possible this afternoon over New
York into southern Vermont with damaging gusts and perhaps a tornado
or two the primary threats. Large to very large hail is possible
with stronger storms over the northern half of Arkansas.

...Northeast southward into the central Appalachians and Cumberland
Plateau...
Water-vapor imagery this morning shows an upper trough over the
mid/upper MS Valley moving east towards the Northeast. A belt of
strong west-southwesterly 500-mb flow (50-65 kt) will overspread
much of the Northeast today in conjunction with the
eastward-migrating shortwave trough. Visible-satellite imagery
shows scattered to broken cloud cover to the south of a west-east
oriented frontal zone extending east from a surface low analyzed
over Lake Huron. Heating of an adequately moist boundary layer
(surface dewpoints in the 56-62 deg F range) will result in weak to
locally moderate buoyancy by midday into the mid afternoon (500-1250
J/kg MLCAPE). Large-scale ascent associated with the approaching
disturbance and convergence in the vicinity of the frontal zone will
lead to scattered storm development this afternoon. Ample mid to
high-level flow will favor storm organization, including the
possibility for a few supercells and an organized band of storms. A
risk for large hail and a tornado could accompany the more intense
cells, whereas the wind risk will tend to focus with linear
structures that evolve. An isolated threat for wind damage and
perhaps hail will extend southward into PA/WV and the Cumberland
Plateau, where a few stronger storms may yield those hazards.

...Mid South...
Satellite imagery shows the trailing portion of the upper shortwave
trough over the western Great Lakes is moving east across OK this
morning. This upper feature and associated mid-level cold pocket
(-16 to -18 deg C at 500 mb) will move across the MO Ozarks and AR
this afternoon. A reservoir of lower 60s deg F surface dewpoints
and strong heating in wake of early day showers and isolated
thunderstorms will favor robust CAPE profiles and elongated mid to
upper portions of the hodograph. Latest guidance shows several
cells developing within a weakly capped airmass by mid afternoon.
The stronger storms will likely become supercells yielding a risk
for large to very large hail (1 to 3 inches in diameter). Modest
low-level flow will tend to limit low-level mesocyclone intensity
and the lessen the overall tornado risk. A couple of smaller
clusters may evolve during the early evening with an isolated wind
threat potentially ensuing before this activity weakens by mid
evening.

...Edwards Plateau into the TX Big Country and western north TX...
Moderate to strong potential instability is forecast to develop
beneath steep lapse rates, along and east of a dryline. Although
neutral to weak shortwave ridging is expected today, some of the
latest model guidance shows isolated to widely scattered storm
development by late afternoon on the northwestern rim of richer
low-level moisture arcing from the Edwards Plateau into western
north TX. Strong heating will likely erode appreciable remaining
convective inhibition by 20-22 UTC. Strong west-southwesterly
100-kt 200-mb flow will elongate hodographs amidst a moderately
buoyant airmass. Widely spaced/isolated supercells will mainly
yield a large hail threat late this afternoon into the early
evening.

..Smith/Dean.. 04/16/2026

$$

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ACUS01 KWNS 161626
SWODY1
SPC AC 161624

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1124 AM CDT Thu Apr 16 2026

Valid 161630Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NEW YORK INTO
SOUTHERN VERMONT AS WELL AS FOR NORTHERN ARKANSAS...SOUTHERN
MISSOURI AND FAR WESTERN TENNESSEE...

...SUMMARY...
Scattered severe thunderstorms are possible this afternoon over New
York into southern Vermont with damaging gusts and perhaps a tornado
or two the primary threats. Large to very large hail is possible
with stronger storms over the northern half of Arkansas.

...Ozark Plateau into the Mid-South...
Recent visible satellite imagery shows some ACCAS across
south-central MO, indicative of low/mid-level warm advection amid
the steep lapse rate environment in place. These steep lapse rates
are forecast to continue spread eastward, while low-level moisture
advection brings low 60s dewpoints northeastward into the region as
well. This will result in a moderate to strongly buoyant airmass
(i.e. MLCAPE from 1500 to 2000 J/kg) by the early afternoon.
Additionally, moderate mid to high level flow will remain in place,
resulting in long hodographs and overall environmental conditions
that are very favorable for supercells capable of large to very
large hail. Latest guidance continues the earlier trends of
developing storms in this area, which match observational
expectations as well. Large to very large hail (1 to 3 inches in
diameter) is possible with any updrafts that mature into supercells.
Low-level flow is weak, keeping tornado probability low but none
zero. Given the modest pocket of mid-level dry air present,
supercells will likely become outflow dominant with time,
supporting the potential for damaging gusts across the region
(particular eastern areas) as well.

...NY/VT/NH southeastward into the central Appalachians...
Recent surface analysis places a low over the eastern
Ontario/southern Quebec border vicinity, with modest surface
troughing extending southeastward from this low across central Lower
MI. Airmass across much of NY is characterized by dewpoints in the
low 60s. Dewpoints should stay in the low 60s throughout the day
despite modest mixing amid diurnal heating. This should result in
airmass destabilization ahead of the modest surface trough, with a
general increase in large-scale ascent beginning during the
afternoon as well. Little to no convective inhibition is
anticipated, supporting the potential for more cellular development
over the warm sector initially, before a more expansive convective
line develops along the eastward-progressing surface trough. Ample
mid to high-level flow will favor storm organization, including a
risk for large hail and a tornado with the more intense discrete
cells. The wind risk will tend to focus with linear structures that
evolve over time. An isolated threat for wind damage and perhaps
hail will extend southward into PA/WV and the Cumberland Plateau,
where a few stronger storms may yield those hazards.

...Edwards Plateau into the TX Big Country and western north TX...
A strongly buoyant and weakly capped airmass is expected to develop
along the dryline extending southwestward from western OK through
the Edwards Plateau. Although neutral to weak shortwave ridging is
expected throughout much of the morning into the late afternoon,
some limited ascent (associated with a weak shortwave trough moving
out of northern Mexico) may begin to spread across the dryline by
early evening. This combined with dryline circulations may be enough
to initiate isolated to widely scattered thunderstorms. Low-level
flow will be weak, but moderate to strong westerly flow aloft will
result in wind profiles very favorable for supercells capable of
large to very large hail. Any storms that develop should weaken
quickly with the onset of nocturnal cooling.

..Mosier/Squitieri.. 04/16/2026

$$

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ACUS01 KWNS 162002
SWODY1
SPC AC 162000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Thu Apr 16 2026

Valid 162000Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NEW YORK
INTO SOUTHERN VERMONT...AND THE OZARKS INTO THE MID-SOUTH...

...SUMMARY...
Scattered severe thunderstorms are possible this afternoon over New
York into southern Vermont with damaging gusts and perhaps a tornado
or two the primary threats. Very large hail and severe gusts are
possible with the stronger storms over the Ozarks into the
Mid-South.

...20Z Update...
The SLGT in the Ozarks/Mid-South was expanded northward into central
MO, where an isolated supercell with a risk of very large hail and
damaging gusts has emerged along the northern periphery of a remnant
cold pool. Farther south within Severe Thunderstorm Watch 127,
several discrete/splitting supercells continue to pose a risk of
very large hail (recent report of 2.75 inches) and locally damaging
wind gusts. With time, this activity may congeal into a loosely
organized cluster, with an increasing risk of damaging wind gusts.
The MRGL risk was also expanded slightly westward into southwest OK,
where boundary-layer cumulus is gradually deepening. Any isolated
storms that can form here will pose a risk of large to very large
hail and severe downbursts. Finally, the MRGL was expanded slightly
westward in southwest TX toward Fort Stockton. While convective
initiation is still in question here, deepening boundary-layer
cumulus along the higher terrain could result in an isolated storm
or two, with a risk of very large hail.

..Weinman.. 04/16/2026

.PREV DISCUSSION... /ISSUED 1124 AM CDT Thu Apr 16 2026/

...Ozark Plateau into the Mid-South...
Recent visible satellite imagery shows some ACCAS across
south-central MO, indicative of low/mid-level warm advection amid
the steep lapse rate environment in place. These steep lapse rates
are forecast to continue spread eastward, while low-level moisture
advection brings low 60s dewpoints northeastward into the region as
well. This will result in a moderate to strongly buoyant airmass
(i.e. MLCAPE from 1500 to 2000 J/kg) by the early afternoon.
Additionally, moderate mid to high level flow will remain in place,
resulting in long hodographs and overall environmental conditions
that are very favorable for supercells capable of large to very
large hail. Latest guidance continues the earlier trends of
developing storms in this area, which match observational
expectations as well. Large to very large hail (1 to 3 inches in
diameter) is possible with any updrafts that mature into supercells.
Low-level flow is weak, keeping tornado probability low but none
zero. Given the modest pocket of mid-level dry air present,
supercells will likely become outflow dominant with time,
supporting the potential for damaging gusts across the region
(particular eastern areas) as well.

...NY/VT/NH southeastward into the central Appalachians...
Recent surface analysis places a low over the eastern
Ontario/southern Quebec border vicinity, with modest surface
troughing extending southeastward from this low across central Lower
MI. Airmass across much of NY is characterized by dewpoints in the
low 60s. Dewpoints should stay in the low 60s throughout the day
despite modest mixing amid diurnal heating. This should result in
airmass destabilization ahead of the modest surface trough, with a
general increase in large-scale ascent beginning during the
afternoon as well. Little to no convective inhibition is
anticipated, supporting the potential for more cellular development
over the warm sector initially, before a more expansive convective
line develops along the eastward-progressing surface trough. Ample
mid to high-level flow will favor storm organization, including a
risk for large hail and a tornado with the more intense discrete
cells. The wind risk will tend to focus with linear structures that
evolve over time. An isolated threat for wind damage and perhaps
hail will extend southward into PA/WV and the Cumberland Plateau,
where a few stronger storms may yield those hazards.

...Edwards Plateau into the TX Big Country and western north TX...
A strongly buoyant and weakly capped airmass is expected to develop
along the dryline extending southwestward from western OK through
the Edwards Plateau. Although neutral to weak shortwave ridging is
expected throughout much of the morning into the late afternoon,
some limited ascent (associated with a weak shortwave trough moving
out of northern Mexico) may begin to spread across the dryline by
early evening. This combined with dryline circulations may be enough
to initiate isolated to widely scattered thunderstorms. Low-level
flow will be weak, but moderate to strong westerly flow aloft will
result in wind profiles very favorable for supercells capable of
large to very large hail. Any storms that develop should weaken
quickly with the onset of nocturnal cooling.

$$

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ACUS01 KWNS 170101
SWODY1
SPC AC 170059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Thu Apr 16 2026

Valid 170100Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING
ACROSS PARTS OF EASTERN NEW YORK INTO WESTERN NEW ENGLAND...PARTS OF
THE OZARK PLATEAU INTO MID SOUTH...AND THE PECOS VALLEY/RIO GRANDE
VALLEY VICINITY...

...SUMMARY...
Widely scattered areas of scattered strong to severe thunderstorm
development are expected to generally wane through mid to late
evening.

...01Z Update...

...Parts of Upstate New York into western New England...
Forcing for ascent accompanying a weak frontal wave is maintaining
an area of scattered stronger storms now overspreading areas to the
northwest of Albany NY, in the presence of strong deep-layer shear.
Instability sampled in the evening sounding from Albany is rather
weak, but profiles might still be supportive of at least some risk
for localized severe wind and hail into mid/late evening as forcing
overspreads parts of southern Vermont, New Hampshire and adjacent
Maine.

...Ozark Plateau into Mid South...
The primary east-southeastward propagating organized storm cluster
appears to be in the process of weakening, as southeasterly near
surface updraft inflow across middle Tennessee becomes less
unstable. However, renewed thunderstorm development persists along
and to the cool side of the trailing convective outflow across the
Missouri Bootheel vicinity, with additional attempts along a diffuse
zone of differential surface heating extending westward across
northern Arkansas. This is occurring beneath warming and more
strongly capping lower/mid-tropospheric air, but given inflow of
potentially sizable CAPE, in the presence of moderate westerly
shear, there remains at least some risk for supercell development
capable of producing large hail this evening.

...West Texas...
Potential for sustained severe thunderstorm development appears low
along the retreating dryline across parts of northwest Texas into
the South Plains overnight.

..Kerr.. 04/17/2026

$$

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ACUS01 KWNS 170602
SWODY1
SPC AC 170600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Apr 17 2026

Valid 171200Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
INTO TONIGHT ACROSS PARTS CENTRAL AND SOUTHWESTERN WISCONSIN...FAR
SOUTHEASTERN MINNESOTA...EASTERN IOWA...MUCH OF NORTHERN AND CENTRAL
ILLINOIS...NORTHERN AND CENTRAL MISSOURI...EASTERN AND SOUTHERN
KANSAS...AND NORTHERN OKLAHOMA...

...SUMMARY...
Widespread strong to severe thunderstorm development appears
possible today into tonight across parts of the Upper Midwest
southward across the lower Missouri Valley into central Great
Plains. Initially this may be accompanied by a risk for large hail
and a few strong tornadoes, before damaging wind gusts become the
most prominent hazard by this evening.

...Discussion...
A couple of notable short wave perturbations have emerged from
splitting larger-scale mid-level troughing now overspreading the
northern Rockies and Great Basin. One, including a remnant embedded
cyclonic circulation, is beginning to accelerate east-northeastward
into and across the central Canadian/U.S. border vicinity. The
other is still digging into the eastern Great Basin, but forecast to
turn across the Wyoming/Colorado Rockies during the day, before
shearing northeastward toward the Upper Midwest. It appears that
this will be preceded by several lower amplitude impulses already
emanating from the subtropical eastern Pacific.

In lower-levels, a significant cold front is already surging
southward to the lee of the northern Rockies and forecast to advance
across much of the remainder of the northern Great Plains by 12Z
this morning. Models indicate that significant cyclogenesis may
subsequently ensue northwest/north of Lake Superior toward James Bay
later today through tonight. At the same time, it appears that a
secondary frontal wave will migrate northeast of the mid Missouri
Valley through the Upper Midwest/Great Lakes vicinity. Another lee
cyclone may attempt to form near/north of the Texas/Oklahoma
Panhandle vicinity, but probably will be overtaken by the southward
surging cold front before migrating out of the high plains.

The northward advection of relatively moist low-level air is ongoing
from the southern into central Great Plains and lower Missouri
Valley, and forecast to continue spreading northward within a
pre-cold frontal plume through portions of the Upper Midwest/Great
Lakes region by this afternoon. Beneath steep lapse rates, this may
contribute to sizable mixed-layer CAPE within a corridor from the
east central Great Plains through the mid/upper Mississippi Valley
by this afternoon.

There is notable spread among the various model output concerning
most of these developments, which may have a significant impact on
the convective evolution and associated severe weather potential
today through tonight. However, potential exists for widespread
convective development capable of producing damaging surface gusts,
large hail and a couple of strong tornadoes.

...Upper Mississippi Valley/Midwest vicinity...
It appears that a corridor of stronger surface pressure falls may
shift from western Iowa north-northeastward through western
Wisconsin by early this afternoon, accompanied by substantive
boundary-layer destabilization and strengthening southerly low-level
wind fields with enlarging hodographs. Based on the latest model
output, including convection allowing guidance, it appears that this
may contribute to a window of opportunity for discrete supercell
development within an environment potentially conducive to strong
tornadoes, before activity grows upscale and eventually outpaces the northeastward boundary-layer destabilization.

...Central Great Plains through middle Mississippi Valley/Midwest...

Uncertainty lingers concerning how quickly the surface cold front
will tend to undercut a developing corridor of stronger pre-frontal
surface heating and destabilization, particularly across the central
into southern Great Plains. However, by early this afternoon, this
corridor appears likely to develop along an axis from south central
Kansas toward northwestern Missouri, providing a focus for rapidly
developing storms including supercells. Initially this may include
hail exceeding 2 inches in diameter, and potential for a few
tornadoes before convection grows upscale, spreads east of the axis
of maximum instability and also become undercut by the front.

Perhaps aided by forcing associated with one of the perturbations
emerging from lower latitudes, there appears a signal in model
output that the upscale growing convection may eventually become
better organized with one or two notable mesoscale convective
vortices evolving while spreading ahead of the front across and
northeast of the lower Missouri Valley late this afternoon and
evening. Downward mixing of strengthening rear-inflow, within a
sheared ambient southwesterly deep-layer mean flow already on the
order of 35-40 kt, widespread strong to severe wind gusts appear
possible, with strongest gusts and/or perhaps brief tornadoes
accompanying evolving mesovortices along the gust front.

The cold front/dryline intersection may become another focus for
discrete supercell development across parts of south central Kansas
into adjacent northwestern Oklahoma by late afternoon. However, the
extent of the associated severe weather potential will depend on how
quickly this activity is overtaken by the cold front.

..Kerr/Lyons.. 04/17/2026

$$

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ACUS01 KWNS 171240
SWODY1
SPC AC 171239

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0739 AM CDT Fri Apr 17 2026

Valid 171300Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
THE UPPER AND MID MISSISSIPPI VALLEY SOUTHWESTWARD INTO KANSAS AND
OKLAHOMA...

...SUMMARY...
Numerous severe thunderstorms are likely this afternoon into tonight
across parts of the Upper Midwest southward across the lower
Missouri Valley into central Great Plains. Initially this may be
accompanied by a risk for large to giant hail and a few strong
tornadoes, before severe wind gusts 60 to 90 mph become the
most prominent hazard by this evening.

...Synopsis...
Surface analysis this morning depicts a front bisecting MN north to
south to a low near the NE-IA-SD border, with the front extending
southwestward into the central High Plains. Water-vapor imagery
shows a prominent upper trough near the MT-ND border
south-southwestward into eastern UT. A belt of increasingly strong southwesterly 500-mb flow will overspread a destabilizing warm
sector today as the upper trough eventually reaches the Upper
Midwest and central Great Plains late tonight. Concurrently, the aforementioned cyclone will develop northeast to Lake Superior as a
warm front over IA advances northward into the western Great Lakes.
Meanwhile, the cold front will sweep southeast reaching the central
Great Lakes southwestward into the southern Great Plains by early
Saturday.

...Upper and Mid Mississippi Valley...
A northward expanding warm/moist sector on the nose of a 50+ kt
southerly LLJ will continue to destabilize as large-scale ascent
approaches from the west. A large-hail threat may develop this
morning with developing convection across southern MN (see
forthcoming MCD #472 for short-term details). Heating and advection
of 60s deg F surface dewpoints beneath steep mid-level lapse rates
will support the development of a moderately to very unstable
airmass from IA-IL northward into the upper MS Valley to the east of
the front and southeast of the low. Upwards of 1500-3000 J/kg
MLCAPE is forecast immediately ahead of the front with strengthening
flow aloft, strongly favoring organized storms, including
supercells. Recent model guidance continues to show the development
of discrete supercells later this afternoon ahead of the front over
parts of central/northern WI near the low, and farther south in the
vicinity of eastern IA into adjacent portions of WI/northwest IL.
All hazards will be possible with this potential activity, including
the possibility for an intense tornado. Large to giant hail will be
possible with supercells. Other storms likely to evolve quickly
into a band of severe thunderstorms will develop farther west and
push east coincident with the front. Damaging wind gusts will tend
to become more prevalent during the evening with linear storm modes.
Some tornado risk may continue into the evening as maturing bands of
storms yield a threat for bowing segments and embedded mesovortices,
before this activity gradually diminishes late as it moves east into
IN/Lower MI late.

...KS-OK eastward into the lower MO Valley...
Continued moistening and heating of an airmass to the east of a
dryline/cold front and associated triple point will lead to a very
unstable airmass from OK into KS by early to mid afternoon. A
capping inversion will likely inhibit storm development until mid
afternoon near the front. Initial storm development will likely be supercellular near the triple point before a more extensive band of
cellular storms develops along the boundary. Both a supercell and
QLCS tornado risk is apparent given the appreciably large
CAPE/shear. A coalescing of cold pools and intensification of a
squall line with embedded surges and bowing segments may result in
focused swaths of more intense severe gusts (i.e., locally 75-90
mph) from south-central and eastern KS into west-central MO.
Farther south, a more conditional setup south of the triple point
along the dryline is expected. Large to giant hail could accompany
any mature/sustained supercell along with a tornado risk.
Eventually the front will sweep southeastward with a convective line
yielding a risk for wind/hail.

..Smith/Dean.. 04/17/2026

$$

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ACUS01 KWNS 171637
SWODY1
SPC AC 171635

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1135 AM CDT Fri Apr 17 2026

Valid 171630Z - 181200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM FAR
NORTHWEST OKLAHOMA THROUGH CENTRAL AND EASTERN KANSAS INTO
WEST-CENTRAL MISSOURI...

...SUMMARY...
Numerous severe thunderstorms are likely this afternoon into tonight
across parts of the Upper Midwest southward across the lower
Missouri Valley and central/southern Great Plains. Initially this
may be accompanied by a risk for large to giant hail and a few
strong tornadoes, before severe wind gusts of 60 to 90 mph become
the most prominent hazard by this evening.

...Synopsis...
Recent surface analysis places a low over south-central MN, with a
cold front extending southwestward to another low over central KS. A
warm front also extends southwestward from the MN low through far
southwest MN and far northern IL into central IN. This warm front is
demarcated well by the 56 deg F isodrosotherm. Farther south, a
dryline extends from the triple point KS low back southwestward
through the TX Panhandle and into far southeast NM. A broad, moist
warm sector exists to the east of the cold front and dryline,
characterized largely by dewpoints in the low to mid 60s.

A well-defined shortwave trough is apparent on satellite imagery,
extending from southern Saskatchewan back southwestward into the
eastern Great Basin. This wave is forecast to continue eastward,
with a attendant increase in the mid-level flow across much of the
Plains and Upper/Mid MS Valley. The cold front will surge eastward/southeastward in response to this wave as well, interacting
with the warm sector to support numerous strong to severe
thunderstorms from parts of the Upper Midwest southward across the
lower Missouri Valley into southern Plains.

...Upper/Mid MS Valley...
Moderate to strong low-level moisture advection is expected across
the Upper MS Valley today as the surface low mentioned in the
synopsis progresses northeastward, with an attendant northward shift
of the warm front as well. The risk across this region may evolve in
several phases, beginning with the elevated thunderstorms currently
ongoing across northwest WI. This storms will likely continue
northeastward, posing a risk for severe hail and isolated damaging
gusts. Additional development is possible northwest of this activity
along the occluded front, with some hail possible here as well.

Farther south, the northeastward advecting low-level moisture
coupled with strong heating and steep lapse rates will result in a
strongly unstable airmass along and just south of the warm front by
the early afternoon. Storm initiation is anticipated within this
open warm sector by early afternoon, forced by a mix of warm-air
advection, low-level confluence, and subtly increasing large-scale
ascent. This activity should be ahead of the front and initially
discrete. The overall parameter space will be characterized by
strong to very strong buoyancy, moderate deep-layer vertical shear,
and strong low-level helicity. Supercells capable of all hazards are
expected, including large to very large (i.e. 3"+ hail), strong to
intense tornadoes, and severe wind gusts. Storm interactions are
expected to strongly influence the tornado risk, with the initially
discrete mode likely becoming messy quickly.

Farther west, other storms are likely to evolve quickly along the
front, developing into a band of severe thunderstorms that will push
east coincident with the front. Damaging wind gusts will tend to
become more prevalent during the evening with linear storm modes.
Some tornado risk may continue into the evening as maturing bands of
storms yield a threat for bowing segments and embedded mesovortices,
before this activity gradually diminishes late as it moves east into
IN/Lower MI late.

...KS/OK/MO...
A very unstable airmass is expected to develop along and ahead of
the triple point over south-central KS an associated cold front and
dryline. Strong low-level convergence will likely lead to initial
storm development near the triple point. This initial activity will
be supercellular and capable of very large to giant hail (over
3-3.5" in diameter). Highest coverage of very large hail is expected
over from far northwest OK into south-central KS. Strong downdrafts
(60 to 80 mph) are possible as well. With a largely
boundary-parallel orientation to the deep-layer shear, the tornado
risk appears relatively lower. However, given the supercell mode and
potential interactions with outflow, a low-probability tornado risk
remains. A more north-south configuration to the dryline supports a
conditional tornado risk into far northwest TX.

With time, upscale growth and the development of a
forward-propagating MCS is anticipated across central and eastern
KS. Very strong gusts (80+ mph) are possible with this MCS.
Additionally, some QLCS tornado risk will exist within this line as
long as it stays ahead of the surging cold front. The front will
continue sweeping southeastward, with storms along this boundary
yielding a risk for wind/hail.

..Mosier/Chalmers.. 04/17/2026

$$

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ACUS01 KWNS 171955
SWODY1
SPC AC 171953

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0253 PM CDT Fri Apr 17 2026

Valid 172000Z - 181200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM FAR
NORTHWEST OKLAHOMA THROUGH CENTRAL AND EASTERN KANSAS INTO
WEST-CENTRAL MISSOURI...

...SUMMARY...
Numerous severe thunderstorms are likely this afternoon into tonight
across parts of the Upper Midwest southward across the lower
Missouri Valley and central/southern Great Plains. Initially this
may be accompanied by a risk for large to giant hail and a few
strong tornadoes, before severe wind gusts of 60 to 90 mph become
the most prominent hazard by this evening.

...20Z Update...
Severe probabilities have been adjusted to account for progression
of the cold front this afternoon. The remainder of the forecast is
unchanged. See MD 475 for short-term details of evolving tornado
risk along the Illinois/Wisconsin border.

..Wendt.. 04/17/2026

.PREV DISCUSSION... /ISSUED 1203 PM CDT Fri Apr 17 2026/

...Synopsis...
Recent surface analysis places a low over south-central MN, with a
cold front extending southwestward to another low over central KS. A
warm front also extends southwestward from the MN low through far
southwest MN and far northern IL into central IN. This warm front is
demarcated well by the 56 deg F isodrosotherm. Farther south, a
dryline extends from the triple point KS low back southwestward
through the TX Panhandle and into far southeast NM. A broad, moist
warm sector exists to the east of the cold front and dryline,
characterized largely by dewpoints in the low to mid 60s.

A well-defined shortwave trough is apparent on satellite imagery,
extending from southern Saskatchewan back southwestward into the
eastern Great Basin. This wave is forecast to continue eastward,
with a attendant increase in the mid-level flow across much of the
Plains and Upper/Mid MS Valley. The cold front will surge eastward/southeastward in response to this wave as well, interacting
with the warm sector to support numerous strong to severe
thunderstorms from parts of the Upper Midwest southward across the
lower Missouri Valley into southern Plains.

...Upper/Mid MS Valley...
Moderate to strong low-level moisture advection is expected across
the Upper MS Valley today as the surface low mentioned in the
synopsis progresses northeastward, with an attendant northward shift
of the warm front as well. The risk across this region may evolve in
several phases, beginning with the elevated thunderstorms currently
ongoing across northwest WI. This storms will likely continue
northeastward, posing a risk for severe hail and isolated damaging
gusts. Additional development is possible northwest of this activity
along the occluded front, with some hail possible here as well.

Farther south, the northeastward advecting low-level moisture
coupled with strong heating and steep lapse rates will result in a
strongly unstable airmass along and just south of the warm front by
the early afternoon. Storm initiation is anticipated within this
open warm sector by early afternoon, forced by a mix of warm-air
advection, low-level confluence, and subtly increasing large-scale
ascent. This activity should be ahead of the front and initially
discrete. The overall parameter space will be characterized by
strong to very strong buoyancy, moderate deep-layer vertical shear,
and strong low-level helicity. Supercells capable of all hazards are
expected, including large to very large (i.e. 3"+ hail), strong to
intense tornadoes, and severe wind gusts. Storm interactions are
expected to strongly influence the tornado risk, with the initially
discrete mode likely becoming messy quickly.

Farther west, other storms are likely to evolve quickly along the
front, developing into a band of severe thunderstorms that will push
east coincident with the front. Damaging wind gusts will tend to
become more prevalent during the evening with linear storm modes.
Some tornado risk may continue into the evening as maturing bands of
storms yield a threat for bowing segments and embedded mesovortices,
before this activity gradually diminishes late as it moves east into
IN/Lower MI late.

...KS/OK/MO...
A very unstable airmass is expected to develop along and ahead of
the triple point over south-central KS an associated cold front and
dryline. Strong low-level convergence will likely lead to initial
storm development near the triple point. This initial activity will
be supercellular and capable of very large to giant hail (over
3-3.5" in diameter). Highest coverage of very large hail is expected
over from far northwest OK into south-central KS. Strong downdrafts
(60 to 80 mph) are possible as well. With a largely
boundary-parallel orientation to the deep-layer shear, the tornado
risk appears relatively lower. However, given the supercell mode and
potential interactions with outflow, a low-probability tornado risk
remains. A more north-south configuration to the dryline supports a
conditional tornado risk into far northwest TX.

With time, upscale growth and the development of a
forward-propagating MCS is anticipated across central and eastern
KS. Very strong gusts (80+ mph) are possible with this MCS.
Additionally, some QLCS tornado risk will exist within this line as
long as it stays ahead of the surging cold front. The front will
continue sweeping southeastward, with storms along this boundary
yielding a risk for wind/hail.

$$

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ACUS01 KWNS 180101
SWODY1
SPC AC 180059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Fri Apr 17 2026

Valid 180100Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
ILLINOIS INTO NORTHEAST MISSOURI...AND OVER NORTHERN OKLAHOMA...

...SUMMARY...
Damaging storms producing wind, hail and isolated tornadoes remain
possible this evening from Illinois into Oklahoma.

...WI/MI into IL and MO...
Supercells have largely merged into a broken line of assorted bows
from far southeast WI across much of northern into western IL and
trailing into northeast MO. The 00Z ILX sounding shows steep lapse
rates aloft and large deep-layer shear, as well as veering winds
with height. Low-level SRH will remain favorable for rotation to
develop at least briefly anywhere within the line, with damaging
winds the most likely threat. Storms have recently become better
organized over central MO, and this activity may affect the St.
Louis area later tonight. For lower MI into northern IN, the
organized line of storms to the west along with a 60 kt low-level
jet suggest at least isolated severe gusts may occur overnight
despite lesser instability.

For more information about Illinois, see mesoscale discussion 484.

...OK...Southeast KS...southwest MO...northwest AR...
Scattered severe cells persist near and north of the cold front
across much of northern OK and extending into southeast KS. Although
the undercutting cold air will likely mitigate wind potential, steep
lapse rates aloft along with ample deep-layer shear will continue to
favor hail. Storm coverage may be more isolated into southwest OK
later tonight, but the environment remains quite favorable for large
hail.

One corridor for possible damaging wind or even a tornado is over
northeast OK into southwest MO. Here, the front is not surging as
fast, and storms over Osage county are already oriented more
favorably N-S relative to the deep-layer shear. A southwest
low-level jet near 50 kt will further support low-level rotation.

..Jewell.. 04/18/2026

$$

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ACUS01 KWNS 180454
SWODY1
SPC AC 180453

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1153 PM CDT Fri Apr 17 2026

Valid 181200Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
UPPER OHIO VALLEY TO THE APPALACHIANS...

...SUMMARY...
Scattered strong to severe thunderstorms capable of damaging winds
and hail will be possible on Saturday across the upper Ohio Valley
and central Appalachians. Isolated severe hail is also possible
across parts of central Texas.

...Synopsis...
A large upper trough with elongated leading speed max will sweep
across the Great Lakes and OH Valley during the day and into the
Appalachians by Sunday morning. Meanwhile, moderate westerlies aloft
will persist across TX with the aid of a subtropical jet.

At the surface, a cold front will move across OH and KY through
early afternoon, and into western NY, PA, and WV late in the day.
This front will also extend far southwestward toward the
northwestern Gulf Coast and into far southern TX. Ahead of the
front, a narrow plume of 50s to lower 60s F dewpoints will exist as
far north as OH and PA, with more robust moisture into TX with upper
60s F dewpoints.

...Upper Ohio Valley/Appalachians...
A remnant line of showers and thunderstorms is expected to persist
near the cold front this morning as it moves across the OH Valley
and toward the lower Great Lakes. Daytime heating will help
destabilize the air mass ahead of this activity, and storm
rejuvenation is expected after 18Z from near Lake Erie into eastern
KY. These storms will mature in the 21-00Z timeframe, affecting
eastern OH, WV, and into PA and possibly southwest NY.

Substantial southwest flow aloft will help to push these storms
quickly east/northeast across the region, and deep-layer shear may
favor scattered cells initially. Marginal hail will be possible,
along with locally strong gusts, especially as storm mode becomes
linear and peak heating has been achieved. Given the narrow
instability axis, storms should wane after sunset.

...South-Central Texas...
Scattered showers and elevated thunderstorms are expected throughout
much of the day as the cold front rapidly undercuts a moist and
unstable air mass. Forecast soundings show MUCAPE parcels rooted in
the 850-700 mb layer, with effective deep-layer shear of 50-60 kt.
Initial activity may develop over central TX during the morning and
through midday, with additional new elevated development translating
southward as the front continually lifts the moist air mass. A few
hail reports at or above 1.00" will be possible.

..Jewell/Moore.. 04/18/2026

$$

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ACUS01 KWNS 181233
SWODY1
SPC AC 181232

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0732 AM CDT Sat Apr 18 2026

Valid 181300Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
UPPER OHIO VALLEY TO THE APPALACHIANS...

...SUMMARY...
Scattered strong to severe thunderstorms capable mainly of damaging
winds will be possible today across the upper Ohio Valley and
central Appalachians.

...Synopsis...
Water-vapor imagery this morning shows a large-scale upper trough
over the Upper Midwest into the south-central Plains. An elongated
mid-level vorticity lobe and associated speed max will quickly move
eastward across the Midwest today and reach the Lower Great Lakes
and upper OH Valley late tonight. Farther south, a belt of strong west-southwesterly flow associated with a subtropical jet will
reside over TX.

A cold front extending from a low near James Bay southward through
the Great Lakes and into TX will continue to push east and southeast
through the period. Convective outflow over the OH Valley to the
east of the front will eventually be overtaken by the front later
today as a band of showers/thunderstorms develops over the upper OH
Valley by early afternoon.

...OH Valley into the Appalachians...
Some heating combined with a gradually moistening airmass (55-60 deg
F surface dewpoints) will result in weak destabilization by midday
as convective development ensues near the preceding outflow/wind
shift and front. Ample mid to high-level flow will aid in some
potential for storm organization, mainly in the form of a few
stronger cells and linear bands. Widely scattered strong to severe
gusts capable of wind damage will likely be the primary hazard, but
an isolated risk for hail or a brief tornado is possible with the
strongest cells. This activity will likely weaken by early evening
as it encounters a slightly drier and less unstable airmass with
east extent.

...Central Texas...
Scattered showers and elevated thunderstorms are expected throughout
much of the day as the cold front rapidly undercuts a moist and
unstable air mass. The 12 UTC Del Rio, TX raob shows an 8.2 deg
C/km 700-500 mb lapse rate. Forecast soundings show MUCAPE parcels
rooted in the 850-700 mb layer, with effective deep-layer shear of
50-60 kt. Although an isolated risk for large hail appears to be
the main hazard with the stronger cells, there has been some
indication that a localized risk for severe gusts could accompany
the strongest cores. For short-term details regarding a risk for
hail/wind with a few stronger thunderstorms this morning extending
from the Concho Valley east-northeast towards DFW, reference MCD
#490.

..Smith/Dean.. 04/18/2026

$$

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ACUS01 KWNS 181605
SWODY1
SPC AC 181603

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1103 AM CDT Sat Apr 18 2026

Valid 181630Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES
REGION....

...SUMMARY...
Widely scattered strong to severe thunderstorms capable mainly of
damaging winds will be possible today across the Upper Ohio Valley
and Lower Great Lakes.

...Upper OH Valley...
Latest surface analysis shows a cold front pushing eastward across
western OH, associated with a band of widespread clouds and light precipitation. Mostly clear skies are present ahead of the front,
where temperatures are warming through the 70s. This will lead to a
corridor of marginal afternoon instability and the potential for
scattered thunderstorm intensification along the front. Forecast
soundings show strong mid-level winds and steep low-level lapse
rates, supportive of strong downdrafts in any vigorous convection.
However, CAM guidance is consistent in showing very few
organized/strong storms through the day. Will maintain the SLGT
risk for the conditional risk of a few damaging wind events, but
with limited confidence.

...TX...
Isolated intense thunderstorms have been ongoing this morning in the post-frontal regime across central TX. These storms have produced
hail and gusty winds for several hours. It appears likely that this
scenario will shift eastward and weaken early this afternoon as the
primary upper jet moves into AR and away from the region, but will
maintain the MRGL risk area for a few more hours and extend it into
parts of AR/LA.

..Hart/Chalmers.. 04/18/2026

$$

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ACUS01 KWNS 182006
SWODY1
SPC AC 182005

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0305 PM CDT Sat Apr 18 2026

Valid 182000Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WITHIN THE
CENTRAL APPALACHIANS INTO THE UPPER OHIO VALLEY VICINITY...AND PARTS
OF CENTRAL TEXAS...

...SUMMARY...
Isolated marginally severe hail is possible in portions of central
Texas. Isolated damaging winds remain possible from the central
Appalachians into the Upper Ohio Valley vicinity.

...20Z Update...
Based on observational trends 15% wind probabilities were removed
from the Upper Ohio Valley vicinity. Wind gusts along with weak,
shallow convection (with little lightning) have generally been in
the 30 kt range with isolated cases of low 40 kt gusts. Isolated
wind damage remains possible, but a more organized threat is not
expected given weak buoyancy downstream. Elsewhere, marginally
severe hail remains possible with isolated, elevated convection in
central Texas.

..Wendt.. 04/18/2026

.PREV DISCUSSION... /ISSUED 1103 AM CDT Sat Apr 18 2026/

...Upper OH Valley...
Latest surface analysis shows a cold front pushing eastward across
western OH, associated with a band of widespread clouds and light precipitation. Mostly clear skies are present ahead of the front,
where temperatures are warming through the 70s. This will lead to a
corridor of marginal afternoon instability and the potential for
scattered thunderstorm intensification along the front. Forecast
soundings show strong mid-level winds and steep low-level lapse
rates, supportive of strong downdrafts in any vigorous convection.
However, CAM guidance is consistent in showing very few
organized/strong storms through the day. Will maintain the SLGT
risk for the conditional risk of a few damaging wind events, but
with limited confidence.

...TX...
Isolated intense thunderstorms have been ongoing this morning in the post-frontal regime across central TX. These storms have produced
hail and gusty winds for several hours. It appears likely that this
scenario will shift eastward and weaken early this afternoon as the
primary upper jet moves into AR and away from the region, but will
maintain the MRGL risk area for a few more hours and extend it into
parts of AR/LA.

$$

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ACUS01 KWNS 190023
SWODY1
SPC AC 190022

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0722 PM CDT Sat Apr 18 2026

Valid 190100Z - 191200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are unlikely through tonight.

...Synopsis...
Little thunderstorm activity is currently present near the cold
front moving across NY and PA, with only isolated lightning flashes
across WV into western VA. Given the loss of heating, and already
minimal instability present, severe storms appear unlikely to
develop.

Farther south, scattered storms exist over northern AL near the
front, and north of the boundary from LA into central TX. In both
these areas, instability is weak, and generally should not support a
severe threat as the surface air mass cools.

..Jewell.. 04/19/2026

$$

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ACUS01 KWNS 190519
SWODY1
SPC AC 190517

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1217 AM CDT Sun Apr 19 2026

Valid 191200Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast today.

...Synopsis...
A large upper trough extending from the Great Lakes into the OH and
TN Valleys will move into the northeastern US today, with a weak
upper ridge across the Rockies. This pattern will favor high
pressure over the central and eastern states, stable conditions and
minimal thunderstorm activity. A cold front associated the eastern
trough will be well off the East Coast by midday, with drying
offshore flow. Minimal instability may yield isolated thunderstorms
over eastern Florida, or perhaps across the Rio Grande Valley where
elevated moisture and weak instability will remain atop the surface
cool layer. In any case, severe storms are not forecast.

..Jewell/Moore.. 04/19/2026

$$

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ACUS01 KWNS 191244
SWODY1
SPC AC 191243

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0743 AM CDT Sun Apr 19 2026

Valid 191300Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast today.

...Synopsis...
Water-vapor imagery this morning shows a large-scale upper trough
from James Bay southward through the Great Lakes and TN Valley. The
upper trough will continue to move east and reach the Lower Great
Lakes and East Coast by daybreak Monday. In the low levels, a cold
front will push east of the Carolina coast by early afternoon.
Surface high pressure will influence conditions across the central
and eastern states in wake of the cold front. Weak instability will
yield isolated thunderstorms over parts of the south Florida,
eastern North Carolina, and weak elevated storms over south Texas.

..Smith/Thompson.. 04/19/2026

$$

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ACUS01 KWNS 191601
SWODY1
SPC AC 191559

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1059 AM CDT Sun Apr 19 2026

Valid 191630Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast today.

...Synopsis...
A shortwave trough currently approaching Baja California will
provide increasing large-scale forcing for ascent over Mexico and
south/west TX today. This will lead to scattered thunderstorms
through the period.

Other isolated afternoon thunderstorms are expected ahead of a
frontal band affecting New England and eastern NC, beneath cold air
aloft in the Lower Great Lakes region, and over south FL. In all of
these areas, weak instability and/or limited vertical shear will
preclude a risk of organized severe storms.

..Hart/Bunting.. 04/19/2026

$$

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ACUS01 KWNS 191957
SWODY1
SPC AC 191955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Sun Apr 19 2026

Valid 192000Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast today.

...20Z Update...
The TSTM area was removed in eastern NC, where the cold front and
related thunderstorm potential has shifted offshore. The TSTM area
was also trimmed behind a band of eastward-moving thunderstorms
departing the New England coast, and no lightning is expected behind
this activity. Farther south in parts of central FL, isolated
thunderstorms are evolving along the sea breeze focused over the
Treasure Coast. While storm coverage and intensity are expected to
remain isolated/marginal, a warm/unstable PBL and around 35 kt of
midlevel flow could support a strong storm or two capable of locally
strong gusts, though this activity is expected to remain sub-severe.

..Weinman.. 04/19/2026

.PREV DISCUSSION... /ISSUED 1059 AM CDT Sun Apr 19 2026/

...Synopsis...
A shortwave trough currently approaching Baja California will
provide increasing large-scale forcing for ascent over Mexico and
south/west TX today. This will lead to scattered thunderstorms
through the period.

Other isolated afternoon thunderstorms are expected ahead of a
frontal band affecting New England and eastern NC, beneath cold air
aloft in the Lower Great Lakes region, and over south FL. In all of
these areas, weak instability and/or limited vertical shear will
preclude a risk of organized severe storms.

$$

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ACUS01 KWNS 200006
SWODY1
SPC AC 200004

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0704 PM CDT Sun Apr 19 2026

Valid 200100Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast.

...Synopsis...
Scattered thunderstorms currently exist along a cold front mainly
over the western Atlantic Ocean, and earlier affected Downeast
Maine. Thunderstorms chances have ended there as the front has now
pushed through the area.

To the west, broken arc of elevated thunderstorms extends from near
El Paso southeastward across the Rio Grande Valley. This area is in
a zone of theta-e advection just off the surface, with unstable
parcels rooted in the 850-700 mb layer. Weak instability will
preclude much of a hail risk, but overall storm chances should
continue to increase into central TX tonight.

..Jewell.. 04/20/2026

$$

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ACUS01 KWNS 200420
SWODY1
SPC AC 200418

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1118 PM CDT Sun Apr 19 2026

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...Synopsis...
An upper trough will exit the northeastern states today, with
northwest flow aloft extending from the northern Plains to the East
Coast. Upper ridging will occur over the Rockies, while a large
upper trough slowly approaches the West Coast.

At the surface, high pressure will result in relatively stable
conditions for much of the central and eastern CONUS, with centers
over the Mid Atlantic and near the northern Gulf Coast.

In the wake of the eastern trough, winds just off the surface will
maintain a zone of elevated moisture and instability over much of
TX, where scattered showers and storms will be most likely. Weak
instability will preclude any severe storm chances there.

To the west, cooling aloft with the approaching upper trough will
support weak instability into parts of OR and WA, with isolated late
day thunderstorms possible over portions of the Cascades.
Small/non-severe hail cannot be ruled out, along with locally gusty
winds mainly in the 00-03Z time frame.

..Jewell/Chalmers.. 04/20/2026

$$

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ACUS01 KWNS 201220
SWODY1
SPC AC 201218

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0718 AM CDT Mon Apr 20 2026

Valid 201300Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...Synopsis...
Water-vapor imagery this morning shows a weak upper trough centered
over AZ and Sonora moving east undercutting a ridge over the
Rockies. This upper feature will move into the southern High Plains
by late tonight. Farther west, a mid- to upper-level low will move
slowly east from the eastern Pacific toward the CA/OR coast.

Scattered showers and weak elevated storms will be possible across a
large portion of TX today. Farther west, isolated to scattered
thunderstorms are possible in association with the weak upper trough
over parts of the Desert Southwest. Primarily diurnal storm
activity over the southern FL Peninsula is expected, as well as
isolated late day thunderstorms over portions of the Cascades.

Elsewhere, surface high pressure will lead to tranquil conditions
across much of the CONUS precluding storm development.

..Smith/Thompson.. 04/20/2026

$$

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ACUS01 KWNS 201554
SWODY1
SPC AC 201552

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1052 AM CDT Mon Apr 20 2026

Valid 201630Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...Synopsis...
An upper impulse will continue to pose a risk of scattered
thunderstorms over parts of NM and south/west TX through the
afternoon, with activity spreading into north-central TX late
tonight.

Other thunderstorms are possible this afternoon and evening over
south FL in a moist and marginally unstable air mass, along the
coast of southern New England, and over portions of OR/WA. In all
areas, weak instability will preclude the risk of organized severe
storms.

..Hart/Flournoy.. 04/20/2026

$$

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ACUS01 KWNS 201947
SWODY1
SPC AC 201946

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 PM CDT Mon Apr 20 2026

Valid 202000Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...20Z Update...
The TSTM area over the coast of southern New England and the
Mid-Atlantic was removed, as large-scale forcing for ascent and
related thunderstorm activity has shifted offshore. Elsewhere, the
previous forecast remains on track.

..Weinman.. 04/20/2026

.PREV DISCUSSION... /ISSUED 1052 AM CDT Mon Apr 20 2026/

...Synopsis...
An upper impulse will continue to pose a risk of scattered
thunderstorms over parts of NM and south/west TX through the
afternoon, with activity spreading into north-central TX late
tonight.

Other thunderstorms are possible this afternoon and evening over
south FL in a moist and marginally unstable air mass, along the
coast of southern New England, and over portions of OR/WA. In all
areas, weak instability will preclude the risk of organized severe
storms.

$$

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ACUS01 KWNS 210058
SWODY1
SPC AC 210057

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Mon Apr 20 2026

Valid 210100Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected through tonight.

...Discussion...
Scattered thunderstorms persist across central and southern TX this
evening, where southerly 850 mb winds are aiding lift/warm advection
atop the relatively cool boundary layer. In addition, a weak wave
aloft is moving across the southern Plains. As such, storms may
increase in coverage through tonight, expanding into northern and
eastern TX. Effective shear will remain weak especially over
northern areas, and severe storms are not expected.

Elsewhere, showers will generally decrease over far southern FL with
the loss of heating. Farther west, an isolated lightning flash
cannot be ruled out over parts of the WA/OR Cascades as an offshore
upper trough slowly pushes east.

..Jewell.. 04/21/2026

$$

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ACUS01 KWNS 210538
SWODY1
SPC AC 210537

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1237 AM CDT Tue Apr 21 2026

Valid 211200Z - 221200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms are expected today over much of Texas, from Illinois
into Ohio, and over portions of central California. Severe weather
is not currently forecast.

...Synopsis...
An upper ridge will move into the Plains as an upper trough moves
inland over the West, with a strong cyclonic speed max moving across
CA and into the Great Basin. Meanwhile, northwest flow aloft will
extend from the Great Lakes into the Mid Atlantic. Farther south, a
weakening disturbance will move out of TX and toward the lower MS
Valley.

At the surface, high pressure will remain over much of the eastern
states and across the Gulf Coast. Southerly winds across the Plains
and around this high may support mid to upper 50s F dewpoints as far
north as IA and IL by 00Z, while higher dewpoints remain relegated
to southern TX. Here, scattered showers and thunderstorms will
likely be ongoing early on Tuesday where weak elevated instability
will remain.

...IL/IN/OH...
A surface trough is forecast to develop from Lower MI into southern
WI and northern IL by late afternoon, beneath the northwest flow
regime and with cool midlevel temperatures. Southwest surface winds
and daytime heating should lead to 40s and 50s F dewpoints, with a
relatively dry boundary layer overall. Models suggest at least
isolated late day and evening thunderstorms will develop ahead of
this trough, though instability levels are uncertain. Despite
marginal dewpoints/moisture, the cool temperatures aloft may support
a few cells capable of small hail from IL into IN by late afternoon.
Wind gust potential is more uncertain and dependent on storm
coverage/outflow production, with the dry boundary layer
conditionally helping strong gust potential into the evening and
perhaps overnight.

...Central CA...
Cold temperatures aloft north of the midlevel jet will support weak
instability over parts of the central Valleys. Given early
precipitation and clouds, as well as marginal low-level shear,
severe storms appear unlikely. However, a few strong storms may
occur late in the afternoon if sufficient heating occurs behind the
early day rain. Small hail appears most probable with the strongest
cells.

..Jewell.. 04/21/2026

$$

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ACUS01 KWNS 211240
SWODY1
SPC AC 211239

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0739 AM CDT Tue Apr 21 2026

Valid 211300Z - 221200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Organized severe thunderstorms are not currently forecast across the
contiguous United States through tonight.

...IL/IN...
Morning water-vapor imagery shows a subtle disturbance over the mid
MO Valley, which is forecast to quickly move southeast into the
southern Great Lakes by early evening. An associated surface trough
is forecast to develop from Lower MI into southern WI and northern
IL by late afternoon. Despite modest moisture (upper 40s to mid 50s
deg F surface dewpoints) returning northward into the Cornbelt, cold
mid-level temperatures (around -16 to -18 deg C at 500 mb) per
forecast soundings and heating will yield weak instability by
mid-late afternoon. Models continue to show isolated to scattered
storms late today into the evening. It remains uncertain whether a
couple of stronger cells will yield a threat of hail beyond a risk
for small hail. This activity will likely diminish by mid-late
evening as it moves southeast into central portions of IL/IN.

...Central CA...
Strong cyclonic flow associated with a mid-level low and associated
trough will move across central CA into the Great Basin during the
period. Cold temperatures aloft north of the midlevel jet will
support weak instability over parts of the central valleys. Given
early precipitation and clouds, as well as marginal low-level shear,
severe storms appear unlikely. However, a few strong storms may
occur late in the afternoon if sufficient heating occurs behind the
early day rain. Small hail appears most probable with the strongest
cells.

..Smith/Thompson.. 04/21/2026

$$

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ACUS01 KWNS 211553
SWODY1
SPC AC 211551

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1051 AM CDT Tue Apr 21 2026

Valid 211630Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
OVER THE CA CENTRAL VALLEY...AND OVER PORTIONS OF NORTHERN IL/IN...

...SUMMARY...
Isolated strong thunderstorms are possible in the California Central
Valley, capable of gusty winds and perhaps a tornado or two. Other
strong storms are possible in parts of northern IN/IL where gusty
winds may occur.

...Central CA...
Morning water vapor loop shows a well-defined shortwave trough
approaching the coast of central CA. An associated mid/upper level
jet will nose into CA, with forcing for ascent in the left-front
quadrant of the jet aiding in the development of afternoon/evening thunderstorms over parts of the Central Valley. Forecast soundings
show steep low and mid level lapse rates and sufficient CAPE for a
few robust updrafts. Vertical shear will be strong enough for
supercell structures, including a risk of a tornado or two, small
hail, and gusty winds.

...Northern IN/IL...
A fast-moving shortwave trough currently over IA/MN will track
quickly southeastward into WI/IL/IN this afternoon. Visible
satellite and radar imagery show a line of high-based thunderstorms
developing ahead of the trough over southern WI. As these storms
track into northern IL/IN, continued heating/weak destabilization
will increase the risk of gusty/locally damaging wind gusts and
small hail in the strongest cores this afternoon.

..Hart/Flournoy.. 04/21/2026

$$

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ACUS01 KWNS 211949
SWODY1
SPC AC 211947

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 PM CDT Tue Apr 21 2026

Valid 212000Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE OHIO VALLEY AND THE CALIFORNIA CENTRAL VALLEY...

...SUMMARY...
Isolated strong thunderstorms are possible in the California Central
Valley, capable of gusty winds and perhaps a tornado or two. Other
strong storms are possible over parts of the Great Lakes region.

...20Z Update...
The primary changes to the outlook were to extend Category
1/Marginal Risk probabilities in CA farther north into the
Sacramento Valley, and expand severe probabilities in the Great
Lakes area to include far southwestern Lower MI. In CA, MRMS mosaic
radar imagery shows convection deepening farther north into the
Sacramento Valley, and where 19Z mesoanalysis shows well over 100
J/kg 0-3 km CAPE in place with a focused corridor of low-level
vertically oriented vorticity. As such, a low-topped supercell could
develop this afternoon or evening, which may be capable of producing
hail/wind and perhaps a brief tornado. Thunderstorms, with a history
of producing marginally severe hail over extreme southeastern WI,
are currently traversing far southern Lake MI, and have been slow to
diminish. A corridor of MUCAPE is developing over far southwestern
Lower MI as 8+ C/km mid-level lapse rates, coinciding with a
southwesterly WAA regime, overspreads the Great Lakes. Therefore,
Category 1/Marginal risk wind/hail probabilities were extended
northeastward into far southwestern Lower MI to account for
potential strong thunderstorms in this region.

..Squitieri.. 04/21/2026

.PREV DISCUSSION... /ISSUED 1051 AM CDT Tue Apr 21 2026/

...Central CA...
Morning water vapor loop shows a well-defined shortwave trough
approaching the coast of central CA. An associated mid/upper level
jet will nose into CA, with forcing for ascent in the left-front
quadrant of the jet aiding in the development of afternoon/evening thunderstorms over parts of the Central Valley. Forecast soundings
show steep low and mid level lapse rates and sufficient CAPE for a
few robust updrafts. Vertical shear will be strong enough for
supercell structures, including a risk of a tornado or two, small
hail, and gusty winds.

...Northern IN/IL...
A fast-moving shortwave trough currently over IA/MN will track
quickly southeastward into WI/IL/IN this afternoon. Visible
satellite and radar imagery show a line of high-based thunderstorms
developing ahead of the trough over southern WI. As these storms
track into northern IL/IN, continued heating/weak destabilization
will increase the risk of gusty/locally damaging wind gusts and
small hail in the strongest cores this afternoon.

$$

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ACUS01 KWNS 220047
SWODY1
SPC AC 220045

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 PM CDT Tue Apr 21 2026

Valid 220100Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SAN JOAQUIN VALLEY OF CENTRAL CALIFORNIA...

...SUMMARY...
Isolated strong thunderstorms are possible in the San Joaquin Valley
of central California early this evening, capable of isolated severe
gusts and perhaps a tornado.

...San Joaquin Valley...
Latest water vapor imagery shows an upper-level low just off the
coast of far northern California. A mid-level jet is wrapped around
the southern edge of the system. Within the left exit region of the
mid-level jet, a couple of strong to severe thunderstorms are
ongoing in the San Joaquin Valley. Strong lift is present along the
northern gradient of the mid-level jet, which is coincident with a
pocket of instability, with the RAP showing MLCAPE in the 250 to 500
J/kg range. Over this area, the mid-level jet is creating deep-layer
shear exceeding 85 knots. This environment will continue support a
marginal severe threat. Isolated severe wind gusts and perhaps a
tornado will be possible for another hour this evening.

..Broyles.. 04/22/2026

$$

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ACUS01 KWNS 220555
SWODY1
SPC AC 220554

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Wed Apr 22 2026

Valid 221200Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE HIGH PLAINS AND FROM NORTHEAST INDIANA INTO CENTRAL AND NORTHERN
OHIO...

...SUMMARY...
Severe thunderstorms with hail and isolated severe gusts will be
possible across parts of the High Plains this afternoon and evening.
Isolated severe gusts and hail will also be possible in parts of
northeast Indiana and Ohio.

...High Plains...
At mid-levels today, heights will fall across much of the High
Plains, as a ridge moves toward the Mississippi Valley and a trough
moves through the Intermountain West. In response, a lee trough will
sharpen across the High Plains. To the east of the surface trough,
moisture advection will take place. Surface dewpoints will increase
into the 55 to 60 F range to the east of a well-developed dryline
extending from west Texas northward into southwest Nebraska.
Although large-scale ascent will be weak along the dryline,
low-level convergence will aid isolated convective initiation during
the mid to late afternoon. The most favorable location for storm
development will be from northwest Kansas into west-central Nebraska
and southern South Dakota, as the low-level jet strengthens in the
late afternoon and early evening. In addition to moderate
instability, 0-6 km shear is forecast to increase into the 35 to 40
knot range by early evening. This, combined with 700-500 mb lapse
rates in the 8.5 to 9 C/km range should be favorable for supercells
with isolated large hail, with the greatest potential from northwest
Kansas into west-central Nebraska. A few severe wind gusts may also
occur from western Kansas into South Dakota.

Further south into west Texas and the Oklahoma Panhandle, the lift
supportive of convective development will be confined to weak
low-level convergence along the dryline. If a storm can initiate,
then a supercell could develop with potential for large hail.

...Northeast Indiana/Central and Northern Ohio...
A mid-level ridge will move into the upper Mississippi Valley today,
as northwesterly mid-level flow persists over the Great Lakes
region. At the surface, a slow-moving front will remain in place
from southern Wisconsin eastward into southern Michigan. Scattered thunderstorms will develop this afternoon along and to the south of
the front as surface temperatures warm and low-level convergence
increases. Model forecasts in the mid to late afternoon from
northeast Indiana into central and northern Ohio have MLCAPE in the
2000 to 2500 J/kg range, with 0-3 km lapse rates near 8.5 C/km. In
addition, 0-6 km shear is forecast to approach 30 knots, which could
be enough for a marginal severe threat. Isolated severe gusts and
hail will be possible with the stronger multicells in areas that
destabilize the most.

..Broyles/Chalmers.. 04/22/2026

$$

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ACUS01 KWNS 221239
SWODY1
SPC AC 221237

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0737 AM CDT Wed Apr 22 2026

Valid 221300Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR PARTS OF THE HIGH PLAINS/NORTHERN PLAINS...AND
FROM NORTHEAST INDIANA INTO NORTHERN OHIO...

...SUMMARY...
Isolated strong-severe thunderstorms with strong gusts and hail will
be possible across parts of the High Plains this afternoon and
evening, as well as from northeast Indiana into northern Ohio.

...High Plains this afternoon/evening...
In response to a shortwave trough digging south-southeastward over
BC/AB, a closed low over the Great Basin will evolve into a more
open wave and eject northeastward to the northern High Plains by
early Thursday. An associated, deep lee cyclone will develop
eastward from MT to near the ND/SK border, with a lee trough
extending southward into the central/southern High Plains. East of
the lee trough, low-level moisture (boundary-layer dewpoints in the
55-60 F range) will spread northward today from TX/OK to KS/NE.
Diurnal mixing will likely limit the quality of the moisture farther
north into the Dakotas. Thus, a few high-based thunderstorms will
be possible this afternoon/evening from NE into SD along the lee
trough with deep mixing, where inverted-v profiles will favor strong
outflow gusts.

A narrow zone of moderate buoyancy is expected along the dryline
from southwest NE and western KS into west TX, where deep-layer
vertical shear will be sufficient for supercells. Only limited
height falls and a warm elevated mixed layer, in combination with
somewhat limited parcel residence times in the dryline circulation,
suggest that storm coverage will be isolated at best. There will be
a conditional threat for isolated large hail with any sustained
storms.

...Dakotas tonight...
The threat for thunderstorms may increase tonight as a result of
ascent preceding the midlevel trough, and a modest increase in
low-level moisture with a strengthening low-level jet. Much of the
convection will likely be rooted above the surface, but could still
produce strong outflow gusts and marginally severe hail.

...IN/OH this afternoon/evening...
Residual low-level moisture and surface heating along a diffuse
baroclinic zone will support thunderstorm development this afternoon
from northeast IN into northern OH. Though deep-layer wind profiles
will not be particularly strong, relatively cool midlevel
temperatures and weak-moderate buoyancy could support marginally
severe hail and gusty outflow winds with the strongest storms.

..Thompson/Bentley.. 04/22/2026

$$

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ACUS01 KWNS 221630
SWODY1
SPC AC 221628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Wed Apr 22 2026

Valid 221630Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR PARTS OF THE HIGH PLAINS/NORTHERN PLAINS...AND
ACROSS FAR SOUTHERN LOWER MICHIGAN...NORTHEAST INDIANA INTO NORTHERN
OHIO...

...SUMMARY...
Isolated strong-severe thunderstorms with strong gusts and hail will
be possible across parts of the High Plains this afternoon and
evening, as well as from northeast Indiana into northern Ohio.

...Synopsis...
Recent surface analysis shows an airmass modifying under low-level
moisture advection across the southern and central Plains, with mid
50s dewpoints reaching through central KS and into eastern
NE/western IA. This moderate low-level moisture also extends
eastward from IA into northern IL and IN, just south of a stationary
boundary that demarcates a drier, more stable airmass across much of
the Great Lakes from the modifying airmass farther south/southwest.

This analysis also reveals a pair of surface lows, one over
north-central MT and the other over far northeast WY/far southeast
MT, linked by modest surface troughing. A wavy surface trough also
extends southward to another low over southeast CO. Thunderstorm
development is anticipated today/tonight near these lows and their
related surface boundaries. In particular, strong to isolated severe thunderstorms appear possible near the northeast WY/far southeast MT
low as it moves eastward across SD, as well as in the vicinity of
the stationary boundary across northern IN and OH.

...IN/OH...
Weak surface low over southern Lower MI has already contributed to
thunderstorm development. The airmass downstream of this low, and
south of the stationary boundary that extends east-to-west near the
MI and IN/OH border vicinity, will likely destabilize throughout the
day amid continued low-level moisture advection and strong diurnal
heating. This destabilization coupled with low-level convergence
near the low and boundary will support increasing thunderstorm
coverage. Deep-layer wind profiles will be modest, but cool
mid-level temperatures and weak-moderate buoyancy could support
isolated severe hail and gusty outflow winds with the strongest
storms.

...High Plains...
Primary surface low over central MT is forecast to deepen today as a
closed upper low currently over the Great Basin ejects northeastward
while evolving towards a more open wave. At the same time, a
secondary surface low (currently over far northeast WY/far southeast
MT) is forecast to move eastward across SD, interacting with the
modifying airmass across the northern/central Plains. Expectation is
for this airmass to be deeply mixed, with perhaps some minimal
buoyancy atop the well-mixed boundary layer. Development of a few
high-based thunderstorms is possible this afternoon/evening from NE
into SD, as well as northeast MT, along the trough where deep mixing
and inverted-v profiles will favor strong outflow gusts.

Farther south, an even more conditional risk is anticipated along a
sharpening dryline from southwest NE and western KS into west TX.
Given the limited large-scale forcing and only weak low-level
convergence, warm mid-level temperatures and related capping
associated with a notable elevated mixed layer will likely suppress thunderstorm development. Here, deep-layer vertical shear will be
sufficient for supercells, and a conditional risk for large hail and
strong gusts exists with any updrafts that are able to persist and
mature.

...Western/Central NE into the Dakotas...
Additional thunderstorms are possible tonight from western/central
NE into the Dakotas as an eastward-progressing cold front interacts
with low-level moisture continuing to advect northward across the
Plains and a strengthening low-level jet. These storms will likely
be elevated behind the front, with some isolated hail possible early
in the convective cycle. Additionally, mid-level dry air will likely
remain across the region, supporting the potential for strong
outflow gusts despite the storms elevated character.

..Mosier/Lyons.. 04/22/2026

$$

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ACUS01 KWNS 221953
SWODY1
SPC AC 221951

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Wed Apr 22 2026

Valid 222000Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE HIGH PLAINS INTO THE NORTHERN PLAINS AND EASTERN PARTS OF THE
OHIO VALLEY...

...SUMMARY...
Isolated strong-severe thunderstorms with strong gusts and hail will
be possible across parts of the High Plains this afternoon and
evening, as well as from northeast Indiana into northern Ohio.

...20Z Update...
The previous forecast (see below) remains on track, with mainly
minor adjustments made to the general thunder and severe
probabilities to reflect the latest observations and guidance
consensus.

..Squitieri/Mosier.. 04/22/2026

.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Apr 22 2026/

...Synopsis...
Recent surface analysis shows an airmass modifying under low-level
moisture advection across the southern and central Plains, with mid
50s dewpoints reaching through central KS and into eastern
NE/western IA. This moderate low-level moisture also extends
eastward from IA into northern IL and IN, just south of a stationary
boundary that demarcates a drier, more stable airmass across much of
the Great Lakes from the modifying airmass farther south/southwest.

This analysis also reveals a pair of surface lows, one over
north-central MT and the other over far northeast WY/far southeast
MT, linked by modest surface troughing. A wavy surface trough also
extends southward to another low over southeast CO. Thunderstorm
development is anticipated today/tonight near these lows and their
related surface boundaries. In particular, strong to isolated severe thunderstorms appear possible near the northeast WY/far southeast MT
low as it moves eastward across SD, as well as in the vicinity of
the stationary boundary across northern IN and OH.

...IN/OH...
Weak surface low over southern Lower MI has already contributed to
thunderstorm development. The airmass downstream of this low, and
south of the stationary boundary that extends east-to-west near the
MI and IN/OH border vicinity, will likely destabilize throughout the
day amid continued low-level moisture advection and strong diurnal
heating. This destabilization coupled with low-level convergence
near the low and boundary will support increasing thunderstorm
coverage. Deep-layer wind profiles will be modest, but cool
mid-level temperatures and weak-moderate buoyancy could support
isolated severe hail and gusty outflow winds with the strongest
storms.

...High Plains...
Primary surface low over central MT is forecast to deepen today as a
closed upper low currently over the Great Basin ejects northeastward
while evolving towards a more open wave. At the same time, a
secondary surface low (currently over far northeast WY/far southeast
MT) is forecast to move eastward across SD, interacting with the
modifying airmass across the northern/central Plains. Expectation is
for this airmass to be deeply mixed, with perhaps some minimal
buoyancy atop the well-mixed boundary layer. Development of a few
high-based thunderstorms is possible this afternoon/evening from NE
into SD, as well as northeast MT, along the trough where deep mixing
and inverted-v profiles will favor strong outflow gusts.

Farther south, an even more conditional risk is anticipated along a
sharpening dryline from southwest NE and western KS into west TX.
Given the limited large-scale forcing and only weak low-level
convergence, warm mid-level temperatures and related capping
associated with a notable elevated mixed layer will likely suppress thunderstorm development. Here, deep-layer vertical shear will be
sufficient for supercells, and a conditional risk for large hail and
strong gusts exists with any updrafts that are able to persist and
mature.

...Western/Central NE into the Dakotas...
Additional thunderstorms are possible tonight from western/central
NE into the Dakotas as an eastward-progressing cold front interacts
with low-level moisture continuing to advect northward across the
Plains and a strengthening low-level jet. These storms will likely
be elevated behind the front, with some isolated hail possible early
in the convective cycle. Additionally, mid-level dry air will likely
remain across the region, supporting the potential for strong
outflow gusts despite the storms elevated character.

$$

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ACUS01 KWNS 230029
SWODY1
SPC AC 230028

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0728 PM CDT Wed Apr 22 2026

Valid 230100Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS...

...SUMMARY...
Thunderstorms with isolated severe gusts and hail will be possible
across parts of the central and northern Plains this evening into
tonight.

...Central and Northern Plains...
Water vapor imagery shows a mid-level low over the northern Rockies,
with cyclonic southwesterly flow located from the Desert Southwest
into the northern Plains. At the surface, a north-to-south oriented
trough is present across the High Plains. Isolated to scattered
thunderstorms are ongoing to the east of the trough from northwest
Nebraska into west-central South Dakota. Additional storms are
ongoing in northeastern Montana to the west of a surface low. As the
low-level jet strengthens across the region tonight, continued
thunderstorm development is expected. A hail and wind-damage threat
will be possible along and near an axis of weak instability from
west-central Nebraska into far southern North Dakota. A wind-damage
threat will also be possible with storms currently ongoing in
northeast Montana.

..Broyles.. 04/23/2026

$$

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ACUS01 KWNS 230503
SWODY1
SPC AC 230502

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1202 AM CDT Thu Apr 23 2026

Valid 231200Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EASTERN KANSAS...

...SUMMARY...
Severe thunderstorms are expected to develop this afternoon and
evening from the southern and central Plains into the lower to mid
Missouri Valley, and upper Mississippi Valley. Tornadoes, large hail
and severe wind gusts will be possible.

...Southern and Central Plains/Lower to Mid Missouri Valley/Upper
Mississippi Valley...
An upper-level trough will move through the central Rockies this
morning, and into the High Plains this afternoon as a 50 to 60 knot
mid-level jet moves into the Great Plains. At the surface, a cold
front will advance southeastward into the mid Missouri Valley and
central Plains. Moisture advection ahead of the front will increase
surface dewpoints into the mid 60s F by afternoon. This will
contribute to moderate destabilization as surface temperatures warm
along the moist axis. Thunderstorms are first expected to develop
ahead of the front over the mid Missouri and upper Mississippi
Valleys in the early to mid afternoon. Convective coverage will
rapidly expand southward into eastern Kansas by late afternoon, and
into far northern Oklahoma during the early to mid evening. MCS
development appears likely to take place along and ahead of the
front.

The best environment for severe storms will be in eastern Kansas. In
this area, RAP forecast soundings late this afternoon ahead of the
front have MLCAPE peaking just above 3000 J/kg, with 700-500 mb
lapse rates in the 7.5 to 8 C/km range. 0-6 km shear is forecast to
be in the 35 to 40 knot range. This environment will support
supercells with large hail. Hailstones greater than 2 inches in
diameter will be possible with the more intense supercells. In
addition, 0-3 km storm-relative helicity is forecast to increase
into the 300 to 400 m2/s2 range by 00Z, as at 40 to 50 knot
low-level jet strengthens. This will support tornadoes with
supercells. Supercells will initially be discrete but a line is
expected to form by early evening. As the line forms, rotating cells
within the line should also be capable of producing tornadoes. A
strong tornado or two will be possible late this afternoon and early
this evening. A wind-damage threat is also expected to develop. The
southern edge of the line will impact far northern Oklahoma in the
early to mid evening. Convective coverage should be isolated further
south across the rest of Oklahoma.

Further north-northeast into Iowa and southern Minnesota,
instability will not be as strong. RAP forecast soundings by late
afternoon have MLCAPE peaking in the 1500 to 2000 J/kg range. This,
combined with 30 to 35 knots of deep-layer shear and 700-500 mb
lapse rates of 7 to 7.5 C/km should support large hail with
supercells. Supercells and developing line segments should also be
capable of producing wind damage, hail and a tornado or two.

..Broyles/Chalmers.. 04/23/2026

$$

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ACUS01 KWNS 231251
SWODY1
SPC AC 231250

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 AM CDT Thu Apr 23 2026

Valid 231300Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATER THIS AFTERNOON/EVENING FOR EASTERN KANSAS INTO EXTREME NORTHERN
OKLAHOMA...

...SUMMARY...
Severe thunderstorms are expected to develop this afternoon and
evening from the southern and central Plains into the lower to mid
Missouri Valley, and upper Mississippi Valley. Tornadoes, large hail
and severe wind gusts will be possible.

...MN/IA to KS/northern OK this afternoon into tonight...
The interaction of a southeastward moving midlevel trough over
southern BC/AB and a northeastward moving trough over the western
Dakotas will lead to the formation of a deep closed low over
southern SK. An associated, occluding surface cyclone will weaken
across southern MB by this evening, as a trailing cold front moves
across MN/IA/KS/MO and northern OK. Low-level moisture will spread
northward across IA/MN in advance of the cold front, beneath the
northeast edge of an elevated mixed layer. Surface heating and the
degree of buoyancy may be limited by extensive clouds from IA into
MN, and forecast wind profiles show complex/messy hodographs
structures (stronger low-level shear lingering across IA). Mixed
convective modes are expected along and ahead of the front this
afternoon, which could produce occasional wind damage, large hail
and perhaps a couple of tornadoes.

The more substantial severe threat is expected late this afternoon
through late evening from eastern KS into far northern OK, near and
just northeast of a cold front/dryline triple point and weak
secondary cyclone. A midlevel speed max near the Four Corners will
progress eastward to the TX Panhandle by this evening, with ascent
in the left exit region of the jet coincident with the triple point
near or just north of the KS/OK border. An influx of mid 60s
boundary-layer dewpoints beneath steep midlevel lapse rates will
contribute to MLCAPE of 2000-3000 J/kg, with weakening convective
inhibition across KS by mid afternoon.

Storm development is expected along the cold front in KS by mid
afternoon, with storms expected to develop southward to near the
triple point. The large buoyancy, steep midlevel lapse rates and
deep-layer shear sufficient for supercells will favor very large
hail (2-3 inches in diameter) with the initial/more discrete storms.
The tornado threat will peak this evening as low-level
shear/hodograph curvature increase near the KS/OK border - there
will be strong tornado potential with the anchor/southern supercells
near the triple point. Upscale storm growth and cold pool
development will favor a more linear convective mode with occasional
wind damage as the outflow/effective cold front spreads
southeastward into northeast OK and southwest MO overnight.

...OK dryline this evening...
Storm development along the dryline in OK is uncertain late this afternoon/evening. Forecast soundings suggest that the degree of
surface heating/mixing along the dryline and residence time in the
dryline circulation will be close to supporting deep convection. If
storms do form, the environment will conditionally favor very large
hail initially, and the possibility of an evening tornado threat
with any sustained storm.

..Thompson/Bentley.. 04/23/2026

$$

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ACUS01 KWNS 231615
SWODY1
SPC AC 231615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
1115 AM CDT Thu Apr 23 2026

Valid 231630Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN
KANSAS...NORTHERN OKLAHOMA...

...SUMMARY...
Severe thunderstorms are expected to develop this afternoon and
evening from the southern and central Plains into the lower to mid
Missouri Valley, and upper Mississippi Valley. Tornadoes, large hail
and severe wind gusts will be possible.

...MN/IA to KS/northern OK this afternoon into tonight...
The interaction of a southeastward moving midlevel trough over
southern BC/AB and a northeastward moving trough over the western
Dakotas will lead to the formation of a deep closed low over
southern SK. An associated, occluding surface cyclone will weaken
across southern MB by this evening, as a trailing cold front moves
across MN/IA/KS/MO and northern OK. Low-level moisture will spread
northward across IA/MN in advance of the cold front, beneath the
northeast edge of an elevated mixed layer. Surface heating and the
degree of buoyancy may be limited by extensive clouds from IA into
MN, and forecast wind profiles show complex/messy hodographs
structures (stronger low-level shear lingering across IA). Mixed
convective modes are expected along and ahead of the front this
afternoon, which could produce occasional wind damage, large hail
and perhaps a couple of tornadoes.

The more substantial severe threat is expected late this afternoon
through late evening from eastern KS into northern OK, near and just
northeast of a cold front/dryline triple point and weak secondary
cyclone. A midlevel speed max near the Four Corners will progress
eastward to the TX Panhandle by this evening, with ascent in the
left exit region of the jet coincident with the triple point near or
just north of the KS/OK border. An influx of mid 60s boundary-layer
dewpoints beneath steep midlevel lapse rates will contribute to
MLCAPE of 2000-3000 J/kg, with weakening convective inhibition
across KS by mid afternoon.

Storm development is expected along the cold front in KS by mid
afternoon, with storms expected to develop southward to near the
triple point. The large buoyancy, steep midlevel lapse rates and
deep-layer shear sufficient for supercells will favor very large
hail (2-3 inches in diameter) with the initial/more discrete storms.
The tornado threat will peak this evening as low-level
shear/hodograph curvature increase near the KS/OK border - there
will be strong tornado potential with the anchor/southern supercells
near the triple point. Upscale storm growth and cold pool
development will favor a more linear convective mode with occasional
wind damage as the outflow/effective cold front spreads
southeastward into northeast OK and southwest MO overnight.

...OK dryline this evening...
Storm development along the dryline in OK is uncertain late this afternoon/evening. Forecast soundings suggest that the degree of
surface heating/mixing along the dryline and residence time in the
dryline circulation will be close to supporting deep convection. If
storms do form, the environment will conditionally favor very large
hail initially, and the possibility of an evening tornado threat
with any sustained storm.

..Afwa.. 04/23/2026

$$

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ACUS01 KWNS 231651
SWODY1
SPC AC 231615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
1115 AM CDT Thu Apr 23 2026

Valid 231630Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN
KANSAS...NORTHERN OKLAHOMA...

...SUMMARY...
Severe thunderstorms are expected to develop this afternoon and
evening from the southern and central Plains into the lower to mid
Missouri Valley, and upper Mississippi Valley. Tornadoes, large hail
and severe wind gusts will be possible.

...MN/IA to KS/northern OK this afternoon into tonight...
The interaction of a southeastward moving midlevel trough over
southern BC/AB and a northeastward moving trough over the western
Dakotas will lead to the formation of a deep closed low over
southern SK. An associated, occluding surface cyclone will weaken
across southern MB by this evening, as a trailing cold front moves
across MN/IA/KS/MO and northern OK. Low-level moisture will spread
northward across IA/MN in advance of the cold front, beneath the
northeast edge of an elevated mixed layer. Surface heating and the
degree of buoyancy may be limited by extensive clouds from IA into
MN, and forecast wind profiles show complex/messy hodographs
structures (stronger low-level shear lingering across IA). Mixed
convective modes are expected along and ahead of the front this
afternoon, which could produce occasional wind damage, large hail
and perhaps a couple of tornadoes.

The more substantial severe threat is expected late this afternoon
through late evening from eastern KS into northern OK, near and just
northeast of a cold front/dryline triple point and weak secondary
cyclone. A midlevel speed max near the Four Corners will progress
eastward to the TX Panhandle by this evening, with ascent in the
left exit region of the jet coincident with the triple point near or
just north of the KS/OK border. An influx of mid 60s boundary-layer
dewpoints beneath steep midlevel lapse rates will contribute to
MLCAPE of 2000-3000 J/kg, with weakening convective inhibition
across KS by mid afternoon.

Storm development is expected along the cold front in KS by mid
afternoon, with storms expected to develop southward to near the
triple point. The large buoyancy, steep midlevel lapse rates and
deep-layer shear sufficient for supercells will favor very large
hail (2-3 inches in diameter) with the initial/more discrete storms.
The tornado threat will peak this evening as low-level
shear/hodograph curvature increase near the KS/OK border - there
will be strong tornado potential with the anchor/southern supercells
near the triple point. Upscale storm growth and cold pool
development will favor a more linear convective mode with occasional
wind damage as the outflow/effective cold front spreads
southeastward into northeast OK and southwest MO overnight.

...OK dryline this evening...
Storm development along the dryline in OK is uncertain late this afternoon/evening. Forecast soundings suggest that the degree of
surface heating/mixing along the dryline and residence time in the
dryline circulation will be close to supporting deep convection. If
storms do form, the environment will conditionally favor very large
hail initially, and the possibility of an evening tornado threat
with any sustained storm.

..Afwa.. 04/23/2026

$$

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ACUS01 KWNS 231945
SWODY1
SPC AC 231945

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
0245 PM CDT Thu Apr 23 2026

Valid 232000Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS NORTH CENTRAL MINNESOTA...EASTERN KANSAS...NORTHERN OKLAHOMA...

...SUMMARY...
Severe thunderstorms are expected to develop this afternoon and
evening from the southern through central Plains and Minnesota into
the lower to mid Missouri Valley, and upper Mississippi Valley.
Tornadoes, large hail and severe wind gusts will be possible.

...MN/IA to KS/northern OK this afternoon into tonight...
The interaction of a southeastward moving midlevel trough over
southern BC/AB and a northeastward moving trough over the western
Dakotas will lead to the formation of a deep closed low over
southern SK. An associated, occluding surface cyclone will weaken
across southern MB by this evening, as a trailing cold front moves
across MN/IA/KS/MO and northern OK. Low-level moisture will spread
northward across IA/MN in advance of the cold front, beneath the
northeast edge of an elevated mixed layer. Surface heating and the
degree of buoyancy may be limited by extensive clouds from IA into
MN, and forecast wind profiles show complex/messy hodographs
structures (stronger low-level shear lingering across IA). Mixed
convective modes are expected along and ahead of the front this
afternoon, which could produce occasional wind damage, large hail
and perhaps a couple of tornadoes.

The more substantial severe threat is expected late this afternoon
through late evening from eastern KS into northern OK, near and just
northeast of a cold front/dryline triple point and weak secondary
cyclone. A midlevel speed max near the Four Corners will progress
eastward to the TX Panhandle by this evening, with ascent in the
left exit region of the jet coincident with the triple point near or
just north of the KS/OK border. An influx of mid 60s boundary-layer
dewpoints beneath steep midlevel lapse rates will contribute to
MLCAPE of 2000-3000 J/kg, with weakening convective inhibition
across KS by mid afternoon.

Storm development is expected along the cold front in KS by mid
afternoon, with storms expected to develop southward to near the
triple point. The large buoyancy, steep midlevel lapse rates and
deep-layer shear sufficient for supercells will favor very large
hail (2-3 inches in diameter) with the initial/more discrete storms.
The tornado threat will peak this evening as low-level
shear/hodograph curvature increase near the KS/OK border - there
will be strong tornado potential with the anchor/southern supercells
near the triple point. Upscale storm growth and cold pool
development will favor a more linear convective mode with occasional
wind damage as the outflow/effective cold front spreads
southeastward into northeast OK and southwest MO overnight.

...OK dryline this evening...
Storm development along the dryline in OK is uncertain late this afternoon/evening. Forecast soundings suggest that the degree of
surface heating/mixing along the dryline and residence time in the
dryline circulation will be close to supporting deep convection. If
storms do form, the environment will conditionally favor very large
hail initially, and the possibility of an evening tornado threat
with any sustained storm.

..Afwa.. 04/23/2026

$$

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ACUS01 KWNS 232024
SWODY1
SPC AC 231945

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
0245 PM CDT Thu Apr 23 2026

Valid 232000Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS NORTH CENTRAL MINNESOTA...EASTERN KANSAS...NORTHERN OKLAHOMA...

...SUMMARY...
Severe thunderstorms are expected to develop this afternoon and
evening from the southern through central Plains and Minnesota into
the lower to mid Missouri Valley, and upper Mississippi Valley.
Tornadoes, large hail and severe wind gusts will be possible.

...MN/IA to KS/northern OK this afternoon into tonight...
The interaction of a southeastward moving midlevel trough over
southern BC/AB and a northeastward moving trough over the western
Dakotas will lead to the formation of a deep closed low over
southern SK. An associated, occluding surface cyclone will weaken
across southern MB by this evening, as a trailing cold front moves
across MN/IA/KS/MO and northern OK. Low-level moisture will spread
northward across IA/MN in advance of the cold front, beneath the
northeast edge of an elevated mixed layer. Surface heating and the
degree of buoyancy may be limited by extensive clouds from IA into
MN, and forecast wind profiles show complex/messy hodographs
structures (stronger low-level shear lingering across IA). Mixed
convective modes are expected along and ahead of the front this
afternoon, which could produce occasional wind damage, large hail
and perhaps a couple of tornadoes.

The more substantial severe threat is expected late this afternoon
through late evening from eastern KS into northern OK, near and just
northeast of a cold front/dryline triple point and weak secondary
cyclone. A midlevel speed max near the Four Corners will progress
eastward to the TX Panhandle by this evening, with ascent in the
left exit region of the jet coincident with the triple point near or
just north of the KS/OK border. An influx of mid 60s boundary-layer
dewpoints beneath steep midlevel lapse rates will contribute to
MLCAPE of 2000-3000 J/kg, with weakening convective inhibition
across KS by mid afternoon.

Storm development is expected along the cold front in KS by mid
afternoon, with storms expected to develop southward to near the
triple point. The large buoyancy, steep midlevel lapse rates and
deep-layer shear sufficient for supercells will favor very large
hail (2-3 inches in diameter) with the initial/more discrete storms.
The tornado threat will peak this evening as low-level
shear/hodograph curvature increase near the KS/OK border - there
will be strong tornado potential with the anchor/southern supercells
near the triple point. Upscale storm growth and cold pool
development will favor a more linear convective mode with occasional
wind damage as the outflow/effective cold front spreads
southeastward into northeast OK and southwest MO overnight.

...OK dryline this evening...
Storm development along the dryline in OK is uncertain late this afternoon/evening. Forecast soundings suggest that the degree of
surface heating/mixing along the dryline and residence time in the
dryline circulation will be close to supporting deep convection. If
storms do form, the environment will conditionally favor very large
hail initially, and the possibility of an evening tornado threat
with any sustained storm.

..Afwa.. 04/23/2026

$$

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ACUS01 KWNS 240101
SWODY1
SPC AC 240059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Thu Apr 23 2026

Valid 240100Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS ARTS OF
EASTERN KANSAS AND NORTHERN OKLAHOMA...

...SUMMARY...
Scattered severe thunderstorms will continue this evening from parts
of the southern and central Plains north-northeastward into the
lower Missouri and upper Mississippi Valleys. Tornadoes, large hail
and severe wind gusts are expected.

...Southern and Central Plains...
Latest water vapor imagery shows an upper-level trough over the
Great Plains, with an associated mid-level jet streak moving through
the base of the trough into the southern Plains. At the surface, a
cold front is advancing southeastward across far southeast Nebraska, east-central Kansas and far northern Oklahoma. Ahead of the front,
multiple line segments are ongoing. These broken lines are embedded
with discrete to semi-discrete supercells. The storms are located
along an axis of moderate to strong instability, with the RAP
showing MLCAPE in the 2500 to 3500 J/kg range. Over the top of this
moist and unstable airmass, flow is westerly around 50 knots. This
is creating moderate to strong deep-layer shear which will continue
to support supercells this evening. Steep mid-level lapse rates
approaching 8 C/km will be favorable for large hail. In addition,
the western edge of a 40 to 50 knot low-level jet will remain in
place over eastern Kansas. WSR-88D VWPs that are sampling the
low-level jet have 0-3 km storm-relative helicity in the 400 to 450
m2/s2 range, which will support a continued tornado threat. In
addition, a threat for wind damage will also continue through the
mid to late evening...see MCD 510.

...Lower Missouri Valley/Upper Mississippi Valley...
Southwesterly mid-level flow is in place over much of the
north-central U.S. At the surface, a cold front is located from
central Minnesota south-southwestward into the mid Missouri Valley.
A line of strong to severe thunderstorms is ongoing ahead of the
front from far southeastern Minnesota into central Iowa and far
northwestern Missouri. Moderate instability is analyzed ahead of the
line, with the RAP showing MLCAPE in the 1500 to 2000 J/kg range.
The thermodynamic environment will continue to be favorable for
isolated large hail. In addition, a 40 to 50 knot jet is analyzed
over east-central Iowa. As the low-level jet strengthens, tornadoes
will be possible with rotating cells embedded in the line. As the
line continues to move eastward through the mid to late evening,
wind damage will be possible with embedded supercells and bowing
line segments.

..Broyles.. 04/24/2026

$$

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