Forum: KrAABy Gamer BBS

HVYSNOW: Probabilistic Heavy Snow And Icing Discussion

From COD Weather Processor @1:2320/107 to All on Friday, October 16, 2026 18:07:42

FOUS11 KWBC 161807
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
207 PM EDT Fri Oct 16 2026

Valid 00Z Sat Oct 17 2026 - 00Z Tue Oct 20 2026

The probability of significant snow and ice across the CONUS is
less than ten percent

Snell

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, October 17, 2026 06:14:26

FOUS11 KWBC 170614
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
214 AM EDT Sat Oct 17 2026

Valid 12Z Sat Oct 17 2026 - 12Z Tue Oct 20 2026

The probability of significant snow and ice across the CONUS is
less than ten percent

Mullinax

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, October 17, 2026 18:40:12

FOUS11 KWBC 171839
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
239 PM EDT Sat Oct 17 2026

Valid 00Z Sun Oct 18 2026 - 00Z Wed Oct 21 2026

The probability of significant snow and ice across the CONUS is
less than ten percent through Tuesday.

Jackson

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sunday, October 18, 2026 11:38:04

FOUS11 KWBC 180846
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
446 AM EDT Sun Oct 18 2026

Valid 12Z Sun Oct 18 2026 - 12Z Wed Oct 21 2026

The probability of significant snow and ice across the CONUS is
less than ten percent through Tuesday.

Mullinax

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sunday, October 18, 2026 17:42:04

FOUS11 KWBC 181741
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
141 PM EDT Sun Oct 18 2026

Valid 00Z Mon Oct 19 2026 - 00Z Thu Oct 22 2026

The probability of significant snow and ice across the CONUS is
less than ten percent through Tuesday.

Snell

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Monday, October 19, 2026 06:22:50

FOUS11 KWBC 190622
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
222 AM EDT Mon Oct 19 2026

Valid 12Z Mon Oct 19 2026 - 12Z Thu Oct 22 2026

...Southern Sierra Nevada...

Day 3...

A highly anomalous upper-low off the Southern CA coast
(standardized anomalies as much as -4 sigma at 500mb and 700mb by 12Z
Wed) will work in tandem with an upper-level ridge over the
Nation's Heartland to tap into rich tropical East Pacific moisture
and direct this moisture at the Southwest U.S.. 850-500mb mean flow
out of the south will provide a favorable setup for upslope-
enhanced precipitation rates long the southern Sierra Nevada. That
said, the antecedent air-mass is not overly cold and the colder
temperatures within the closed low are well offshore. This will
keep snowfall confined to the higher elevations of the southern
Sierra Nevada on Wednesday (above 9,000ft). The Probabilistic
Precipitation Portal (PPP) shows low chances (10-30%) for snowfall
totals >4" above 10,000ft. The Probabilistic Winter Storm Severity
Index (WSSI-P) also show low chances (10-30%) as low as 9,000ft in
elevations. This could result in some slick conditions in the
rugged terrain of the southern Sierra Nevada mid-week.

Mullinax

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Monday, October 19, 2026 18:57:22

FOUS11 KWBC 191856
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
256 PM EDT Mon Oct 19 2026

Valid 00Z Tue Oct 20 2026 - 00Z Fri Oct 23 2026

...Southern Sierra Nevada...

Day 2-3...

An anomalously deep mid and upper-level low off the Southern CA
coast (with progged heights below all values in the CFSR
climatology for this time of year valid at 12Z Wednesday) will
direct rich tropical moisture from the east Pacific into the
Southwest U.S. mid to late week. At the same time, increasing
diffluence coupled with a strong 110kt 300mb jet on the downstream
flank of the mid/upper low will overspread southern California,
allowing large scale forcing for ascent to become maximized. The
fetch of tropical moisture combined with the increasing large scale
forcing will lead to the development of widespread low elevation
rain and high elevation snow across the region beginning Wednesday
night and continuing through the day on Thursday. 850-500mb mean
flow out of the south will foster a favorable setup for moderate to occasionally heavy precipitation rates along upslope favored
terrain of the southern Sierra Nevada. However, the air mass in
place ahead of the low is not overly cold and the colder
temperatures within the closed low largely stay well offshore
through the forecast period. As a result, most of the accumulating
snow will fall above 8,000-9,000ft through 00Z Friday, with the
highest amounts above 10,000-11,000ft.

Probabilities for snowfall accumulations greater than 4" have
increased to roughly 20-50% above 9,000ft, and 50-90% above
10,000-11,000ft. Additionally, the probability for greater than 8"
above 10,000-11,000ft is up to roughly 50-80 percent. The
Probabilistic Winter Storm Severity Index (WSSI-P) shows low
chances (10-30%) for moderate impacts as low as 9,000ft, and low to
medium chances (30-50%) above 10,000-11,000ft. This all suggests
that there could be slick and snow-covered roads and passes in the
highest terrain of the southern Sierra Nevada mid to late week.

Miller

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tuesday, October 20, 2026 07:12:04

FOUS11 KWBC 200711
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
311 AM EDT Tue Oct 20 2026

Valid 12Z Tue Oct 20 2026 - 12Z Fri Oct 23 2026

...Southern Sierra Nevada...

Days 2 & 3...

A closed low off the Southern CA coast will tap into moisture
originating from the tropical East Pacific and direct it northward
into the Sierra Nevada both Wednesday and Thursday. The Sierra
Nevada also reside beneath a potent 120kt+ jet streak that will
provide upper-level ascent aloft in addition to the
topographically-induced ascent that supports upslope-enhanced
precipitation rates. The lack of a sufficiently cold air-mass and
the closed low opening up upon approach on Thursday will confine
the heaviest snowfall to be above 10,000ft, although some 3-6"
amounts could occur as low as 9,000ft. The Probabilistic
Precipitation Portal (PPP) depicts moderate-to-high chances
(40-70%) for snowfall totals >8" and low chances (10-30%) for
snowfall >12" at elevations above 10,000ft through Thursday night.
The WSSI-P does show high chances (>70%) for Minor Impacts (winter
driving conditions, use caution while driving) and low-to-moderate
chances for Moderate Impacts (hazardous conditions, closures and
disruptions possible) above 9,000ft. The lower SLRs (topping out
between 10-11:1) will make for generally a heavy, wet snowfall in
the Sierra Nevada.

Mullinax

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tuesday, October 20, 2026 19:49:08

FOUS11 KWBC 201948
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
348 PM EDT Tue Oct 20 2026

Valid 00Z Wed Oct 21 2026 - 00Z Sat Oct 24 2026

...Southern Sierra Nevada...

Days 1-2...

An anomalously deep closed low spinning off the coast of southern
CA will direct a plume of tropical moisture from the eastern
Pacific northward into the Sierra Nevada through mid to late week.
As the low approaches the coast, a potent 120kt+ upper-level jet
streak will overspread the region, leading to an increase in broad
large scale forcing for ascent. The moisture combined with
increasing dynamic forcing will lead to widespread moderate to
occasionally heavy high elevation mountain snow from Wednesday
evening/night through Thursday evening. Aiding precipitation
production will be the modestly strong low to mid level flow
favorably oriented to the rugged terrain of the Sierra Nevada,
which will also support upslope-enhanced precipitation rates. In
fact, the 12Z HREF/REFS both highlight the potential for bursts of
heavier snow with probabilities of 20-40 percent for >1"/hr
snowfall rates, mainly later Wednesday night into Thursday morning.
With that being said, the lack of a sufficiently cold air mass
ahead of the low in addition to the low filling and opening up as
it lifts northeastward into the Great Basin Thursday into Friday
will keep the heaviest snowfall confined to above 9,000-10,000ft.

The Probabilistic Precipitation Portal (PPP) depicts moderate to
high chances (40-80%) for snowfall totals >8" and low to moderate
chances (20-50%) for snowfall >12" at elevations above
9,000-10,000ft through Thursday night. The WSSI-P shows high
chances (>70 percent) for Minor Impacts and low to moderate chances
(30-70 percent) for Moderate Impacts mainly above 10,000-11,000ft.
The enhanced moisture and marginal thermals in play will keep SLRs
mostly below 11:1, which will make for a heavy, wet snowfall in
the Sierra Nevada.

As the system moves into the northern Intermountain West/Rockies
Thursday night into Friday, locally heavy snow will be possible
across some of the higher elevations of southwest MT, western WY, south- central ID, as well as the eastern Uintas in northeast UT and the
San Juans in southwest CO.

The probability of significant ice across the CONUS is less than 10
percent.

Miller

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wednesday, October 21, 2026 06:20:26

FOUS11 KWBC 210619
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
219 AM EDT Wed Oct 21 2026

Valid 12Z Wed Oct 21 2026 - 12Z Sat Oct 24 2026

...Southern Sierra Nevada...
Days 1-2...

The closed upper-low off the Southern CA coast will direct a plume
of tropical moisture at the Southwest U.S. today and into Thursday.
Some of this moisture source will be directed at the southern
Sierra Nevada where a combination of topographically-induced
upslope flow and synoptic scale support in the form of a 120kt+
250mb jet streak will aid in enhanced precipitation rates and
mountain snow. Latest 00Z HREF/REFS probabilistic guidance shows low-to-moderate chances (30-50%) for >1"/hr snowfall rates
Wednesday night and into Thursday morning. These snowfall rates
will be observed higher up in the southern Sierra Nevada with most
areas above 9,000ft witnessing these potential snowfall rates. Snow
is expected to taper off Thursday night. The Probabilistic
Precipitation Portal (PPP) does show moderate-to-high chances
(50-80%) for snowfall totals >6" above 9,000ft in elevation, with
low chances (10-30%) for snowfall amounts exceeding 12" above
11,000ft. The WSSI shows Minor Impacts are anticipated for
elevations at/above 9,000ft, indicating winter driving conditions
are expected and to exercise caution when driving in at those
elevations.

...Central Rockies...
Days 2-3...

The same closed low responsible for the heavy snow in the Sierra
Nevada will work in tandem with upper-level ridging over the
South Central U.S. to project an impressive IVT into the
Intermountain West. By 18Z Thursday, the IVT is surpassing 500
kg/m/s in eastern AZ and eastern UT, which is surpassing the
maximum observed values in the CFSR climatology (1979-2009). This
highly anomalous moisture transport will upslope into various
mountain ranges throughout the Intermountain West (San Juan, NV
Great Basin ridge, Wasatch, Wind River, Tetons, Absaroka). Most
accumulations will be on the minor side given the lack of a
sufficiently cold air-mass. Thursday is the snowier day for the San
Juan Mountains, while Friday is the snowier day for the mountains
ranges across UT, NV, ID, southwest MT, and western WY.

Latest PPP shows low-to-moderate chances (30-50%) for snowfall
totals >6" in the more remote elevations of the San Juan, Teton,
Wind River, and Absaroka Ranges. Localized snowfall amounts
approaching 12" in the peaks on the San Juan Mountains are
possible, especially where hourly snowfall rates >1"/hr occur. The
WSSI-P shows <20% odds for Moderate Impacts throughout the
Intermountain West. Some travel disruptions at pass levels are
possible given the moderate-to-high chances (50-80%) for Minor
Impacts in parts of the San Juan, Tetons, and Absaroka most
notably.

The probability of significant ice across the CONUS is less
than 10 percent.

Mullinax

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wednesday, October 21, 2026 18:21:30

FOUS11 KWBC 211821
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
221 PM EDT Wed Oct 21 2026

Valid 00Z Thu Oct 22 2026 - 00Z Sun Oct 25 2026

...Southern Sierra Nevada...
Days 1-2...

The closed upper-low off the Southern CA coast will direct a plume
of tropical moisture at the Southwest U.S. this evening and into
Thursday. Some of this moisture source will be directed at the
southern Sierra Nevada where a combination of topographically-
induced upslope flow and synoptic scale support in the form of a
120kt+ 250mb jet streak will aid in enhanced precipitation rates
and mountain snow. Latest 12Z HREF/REFS probabilistic guidance
shows low-to-moderate chances (30-50%) for >1"/hr snowfall rates
overnight and into Thursday morning. These snowfall rates will be
observed higher up in the southern Sierra Nevada with most areas
above 9,000ft witnessing these potential snowfall rates. Snow is
expected to taper off Thursday night as the upper low shifts to the north-northeast. The Probabilistic Precipitation Portal (PPP) does
show moderate- to- high chances (40-80%) for snowfall totals >6"
above 9,000ft in elevation, with low chances (10-30%) for snowfall
amounts exceeding 12" above 11,000ft. The WSSI shows Minor Impacts
are anticipated for elevations at/above 9,000ft, indicating winter
driving conditions are expected and to exercise caution when
driving in at those elevations.

...Northern & Central Rockies...
Days 2-3...

The same closed low responsible for the heavy snow in the Sierra
Nevada will work in tandem with upper-level ridging over the
South Central U.S. to project an impressive IVT into the
Intermountain West. By 18Z Thursday, the IVT is surpassing 500
kg/m/s in northeastern AZ and eastern UT, which is surpassing the
maximum observed values in the CFSR climatology (1979-2009). This
highly anomalous moisture transport will upslope into various
mountain ranges throughout the Intermountain West (San Juan, NV
Great Basin ridge, Wasatch, Wind River, Tetons, Absaroka). Most
accumulations will be on the minor side given the lack of a
sufficiently cold air-mass and high snow-levels. In fact, snow
levels start above 13,000ft tonight across the San Juans and even
over 11,000ft over the northern Rockies once precipitation enters
the region Friday morning. Snow levels decline by Friday evening to
around 5,000-6,000ft in the northern Rockies and 8,000ft-10,000 ft
in the central Great Basin/Rockies. Still, thursday is the snowier
day for the San Juan Mountains, while Friday is the snowier day
for the mountains ranges across UT, NV, ID, southwest MT, and
western WY as the moisture surge crosses the region.

Latest PPP shows low-to-moderate chances (30-50%) for snowfall
totals >6" in the more remote high elevations of the San Juan,
Teton, Wind River, and Absaroka Ranges. Localized snowfall amounts
approaching 12" in the peaks on the San Juan Mountains are
possible, especially where hourly snowfall rates >1"/hr occur. The
WSSI-P shows <20% odds for Moderate Impacts throughout the
Intermountain West. Some travel disruptions at pass levels are
possible given the moderate-to-high chances (50-80%) for Minor
Impacts in parts of the San Juan, Tetons, and Absaroka most
notably.

The probability of significant ice across the CONUS is less
than 10 percent.

Mullinax/Snell

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thursday, October 22, 2026 07:26:44

FOUS11 KWBC 220726
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
326 AM EDT Thu Oct 22 2026

Valid 12Z Thu Oct 22 2026 - 12Z Sun Oct 25 2026

...High Sierra Nevada...
Day 1...

A low pressure system tracks east-northeast from the central
California coast this morning to central Nevada by this evening. A
strong moisture plume in advance will continue to produce heavy
precip with snow levels around 9000ft on the southern Sierra Nevada
rest of tonight. Light to moderate snow can be expected this
afternoon under the upper low with snow levels dipping to around
8000ft. Snow tapers off this evening. Day 1 probs for >4"
additional snow after 12Z are 30-60% on the High Sierra.

...Northern Rockies...
Day 2...

The low crossing Nevada tonight opens into a neutrally-tilted
trough as it tracks northeast over Idaho and Montana on Friday.
Warm air advection ahead of the low brings moderate precip rates,
but high snow levels over 9000ft at onset Friday morning with
levels dropping to around 6000ft Friday afternoon under the trough
axis in ID/MT (and staying 8000ft through the event in Wyoming).
Day 2 snow probs for >4" are 30-70% for higher terrain from
central ID through west-central MT as well as the Tetons and Wind
River in WY. Most guidance highlights the Beartooth range in
southwest MT where a foot of snow is possible.

...Colorado...
Days 1-3...

Warm air advection over the San Juans in CO brings moderate to
heavy precip into Friday morning. Snow levels are exceedingly high,
around 13,000ft today before dipping to 11,000ft tonight. Day 1
snow probs for >4" are 30-60% for the highest terrain with Day 2
around 20% for lingering snow Friday morning.

A shortwave that breaks open the low over the Great Basin tonight
swings over southern CA Friday before stalling/closing into a low
over the lower CO River Friday night. This low then tracks to
southern UT through Saturday night. Moderate precip rates return
ahead of the low with snow levels dropping to around 9000ft with
height falls. Day 3 snow probs for >4" are 40-80% for much of the
San Juans and 30-70% for the Sawatch and Mosquito Ranges in central
CO.

The probability of significant ice across the CONUS is less
than 10 percent.

Jackson

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thursday, October 22, 2026 18:22:24

FOUS11 KWBC 221822
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
222 PM EDT Thu Oct 22 2026

Valid 00Z Fri Oct 23 2026 - 00Z Mon Oct 26 2026

...High Sierra Nevada...
Day 1...

A low pressure system tracking northeast from central Nevada this
evening into the Pacific Northwest late tonight is producing
periods of heavy snow across the High Sierra Nevada. The departure
of the low will result in tapering snowfall rates, with little
additional accumulation expected this evening.

...Northern Rockies...
Days 1-2...

The low crossing Nevada tonight opens into a neutrally-tilted
trough as it tracks northeast over Idaho and Montana on Friday.
Warm air advection ahead of the low brings moderate precip rates,
but high snow levels over 9,000ft at onset Friday morning with
levels dropping to around 5,500ft Friday afternoon under the
trough axis in ID/MT (and staying above 8,000ft through the event
in Wyoming) will greatly limit the areal coverage of
significant accumulations to the higher summits . Day 1 snow probs
for >4" are 40-80% for higher terrain from central ID through
west-central MT as well as the Tetons and Wind River in WY. Most
guidance highlights the Beartooth range in southwest MT where a
foot of snow is possible.

...Colorado...
Days 1-3...

Warm air advection over the San Juans in CO brings moderate to
heavy precip into Friday morning. Snow levels are exceedingly high,
around 13,000ft today before dipping to 11,000ft tonight. Day 1
snow probs for >4" are 40-80% for the highest terrain.

A shortwave that breaks open the low over the Great Basin tonight
swings over southern CA Friday before stalling/closing into a low
over the lower CO River Friday night. This low then tracks to
southern UT through Saturday night. Moderate precip rates return
ahead of the low with snow levels dropping to around 9,500ft with
height falls. Day 3 snow probs for >4" are 60-100% for much of the
San Juans and 50-80% for the Sawatch and Mosquito Ranges in
central CO.

The probability of significant ice across the CONUS is less
than 10 percent.

Wegman

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Friday, October 23, 2026 07:12:44

FOUS11 KWBC 230712
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
312 AM EDT Fri Oct 23 2026

Valid 12Z Fri Oct 23 2026 - 12Z Mon Oct 26 2026

...Northern Rockies...
Day 1...

Neutrally-tilted trough tracks northeast from central Nevada over
Idaho and Montana through this evening. Warm air advection ahead
of the low brings moderate precip rates, but high snow levels over
9,000ft this morning with levels dropping to around 6000ft this
afternoon under the trough axis in ID/MT (while staying above
7500ft through the event in Wyoming) will limit significant
accumulations to the higher summits. Banding is expected as snow
levels drop to around 5000ft in west-central MT this evening before
tapering off. Day 1 snow probs for >6" are 40-70% for higher
terrain from central ID through southwest MT with up to 80% for the
Tetons and Wind River in WY and the Beartooth range in southwest
MT where 10" snow is possible. Precip weakens and shifts east late
tonight, bringing a quick end to accumulating snow.

...Colorado...
Days 1-2...

Main band of heavy precip has shifted east of the San Juans in CO
early this morning. brings moderate to heavy precip into Friday
morning. Snow levels are high, around 11,000ft today. Day 1 snow
probs for >4" are 40-80% for the highest terrain.

A southern shortwave trough closes into a low over the CA/AZ border
this evening before tracking to the Four Corners through Sunday.
Snow levels drop to around 9000ft with moderate precip rates. Day
2 snow probs for >6" are 50-80% for much of the San Juans and
30-50% for the Sawatch and Mosquito Ranges in central CO. The
precip plume shifts east of the Rockies by Sunday night.

The probability of significant ice across the CONUS is less
than 10 percent.

Jackson

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Friday, October 23, 2026 19:40:22

FOUS11 KWBC 231939
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
339 PM EDT Fri Oct 23 2026

Valid 00Z Sat Oct 24 2026 - 00Z Tue Oct 27 2026

...Northern Rockies...
Day 1...

An upper trough will move out of southwestern MT this evening and
into Canada overnight. Ongoing mountain snow will accumulate
several inches after 00Z above about 5000ft or so before ending
06-09Z. Snow could fall moderate-heavy at times in banded areas
with 1"/hr rates around 00Z this evening. WPC probabilities for at
least an additional 4 inches of snow are highest (>50%) above
5000ft.

...Colorado...
Days 1-2...

Southern portion of the northern upper trough will split off and
dig through the lower CO River Valley Saturday before lifting
across the Four Corners region Sunday. Southerly flow will bring in
a moderate moisture plume but with high snow levels around
11,000ft Saturday. Those will fall to around 9000ft with increasing
snow rates and modest snow accumulations in the higher terrain of
the San Juans and CO ranges. There, WPC probabilities for at least
8 inches of snow are >50% above about 10,000ft or so. Snow will
lighten and end from southwest to northeast on Sunday night.

For Day 3, the probability of significant snowfall across the
CONUS is less than 10 percent.

For Days 1-3, the probability of significant ice across the CONUS
is less than 10 percent.

Fracasso

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, October 24, 2026 06:43:26

FOUS11 KWBC 240642
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
242 AM EDT Sat Oct 24 2026

Valid 12Z Sat Oct 24 2026 - 12Z Tue Oct 27 2026

...Colorado...
Day 1...

Mid-level low over southern California lifts northeast to the Four
Corners through tonight. Southerly flow in advance will bring
moderate precip rates and high snow levels over Colorado around
11,000ft today before dropping to 9000ft tonight as rates decrease
under height falls. Day 1 PWPF for >6" snow are 30-60% in the
higher Sangre de Cristo, Sawatch, and Mosquito ranged and 50-90%
for the higher San Juans.

...Northern Plains...
Day 3...

THe Four Corners low opens to a trough Sunday morning and ejects north-northeast and becomes positively tilted over the northern
Plains on Monday. Enough comma head expansion of precip occurs to
have some snow bands on the outer northwest side of the precip
shield. This could intersect with the Black Hills and could also
have dynamic enough banding for some snow accum in northwest
South Dakota and central North Dakota. As of now the potential is
for 1-2", but given the negative tilt and available cold air from a
Canadian Prairies surface high, some decent snow banding may
occur.

For Days 1-3, the probability of significant ice across the CONUS
is less than 10 percent.

Jackson

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, October 24, 2026 18:46:34

FOUS11 KWBC 241846
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
246 PM EDT Sat Oct 24 2026

Valid 00Z Sun Oct 25 2026 - 00Z Wed Oct 28 2026

...Colorado...
Day 1...

An upper low over northwestern Arizona this evening will lift
northeastward across the Four Corners overnight. Southerly flow in
advance of the low will bring moderate precip rates and high snow
levels over Colorado around 9000ft tonight as rates decrease under
height falls. The probabilities for an additional 6 inches of snow
after 00Z are highest in the higher Sangre de Cristos and
especially the higher San Juan Mountains.

...Northern Plains...
Days 2-3...

The Four Corners low will mostly open to a trough by Monday and
eject across the northern Plains. With surface low pressure moving
across eastern SD Monday night, enough comma head expansion of
precip should occur to have some snow bands on the outer northwest
side of the precip shield. This could intersect with the Black
Hills and could also have dynamic enough banding for some snow
accumulation in northwestern South Dakota and south central North
Dakota. Temperatures are marginal, but any snow that falls before
sunrise would have a better chance of accumulating. Most likely
forecast is for a broad T-0.5" snow with some potential for an axis
of 1-2" from the Black Hills northeastward. The probability of at
least 2" from the Probabilistic Precipitation Portal is about
20-55% along the ND/SD border southwest of Bismarck, but the 90th
percentile is around 4".

For Days 1-3, the probability of significant ice across the CONUS
is less than 10 percent.

Fracasso/Jackson

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, October 24, 2026 19:21:36

FOUS11 KWBC 241921
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
321 PM EDT Sat Oct 24 2026

Valid 00Z Sun Oct 25 2026 - 00Z Wed Oct 28 2026

...Colorado...
Day 1...

An upper low over northwestern Arizona this evening will lift
northeastward across the Four Corners overnight. Southerly flow in
advance of the low will bring moderate precip rates and high snow
levels over Colorado around 9000ft tonight as rates decrease under
height falls. The probabilities for an additional 6 inches of snow
after 00Z are highest in the higher Sangre de Cristos and
especially the higher San Juan Mountains.

...Northern Plains...
Days 2-3...

The Four Corners low will mostly open to a trough by Monday and
eject across the northern Plains. With surface low pressure moving
across eastern SD Monday night, enough comma head expansion of
precip should occur to have some snow bands on the outer northwest
side of the precip shield. This could intersect with the Black
Hills and could also have dynamic enough banding for some snow
accumulation in northwestern South Dakota and south central North
Dakota. Temperatures are marginal, but any snow that falls before
sunrise would have a better chance of accumulating. Most likely
forecast is for a broad T-0.5" snow with some potential for an axis
of 1-2" from the Black Hills northeastward. The probability of at
least 2" from the Probabilistic Precipitation Portal is about
20-55% along the ND/SD border southwest of Bismarck, but the 90th
percentile is around 4".

...Northern Rockies...
Day 3...

An upper low along the WA/OR coast Monday will push inland and
cross the Divide early Tuesday, spreading valley rain and mountain
snow to Wyoming, Idaho, and western Montana. Snow levels will hover
around 5000-7000ft through Tuesday evening with snow continuing
into early Wednesday. The probability of at least 6 inches of snow
by 00Z Wednesday is >50% above about 8000ft where liquid amounts
will be highest as well.

For Days 1-3, the probability of significant ice across the CONUS
is less than 10 percent.

Fracasso/Jackson

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sunday, October 25, 2026 08:07:58

FOUS11 KWBC 250807
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
407 AM EDT Sun Oct 25 2026

Valid 12Z Sun Oct 25 2026 - 12Z Wed Oct 28 2026

...Colorado...
Day 1...

An upper low over northern Arizona will open into a trough as it
lifts northeast to Colorado through today. Height falls will bring
snow levels down to around 9000ft today over CO terrain. Showery
activity will lead to additional accumulation. Snow probs for >4
inches additional after 12Z are 30-60% in the higher Sangre de
Cristo and San Juan Mountains.

...Northern Plains...
Days 2-3...

The upper low crossing Colorado today will open to a trough that
takes on a negative-tilt Monday as it lifts over the Northern
Plains. The surface low track is across Kansas and eastern
Nebraska Monday with enough comma head precip expansion to have
some snow bands on the northwest side of the precip shield. This
should intersect with the Black Hills Monday along with dynamic
enough banding for some snow accumulation in northwestern South
Dakota and south-central North Dakota. Temperatures are marginal,
but any snow that falls before sunrise would have a better chance
of accumulating. Most likely forecast is for a broad swath of T-0.5"
snow with some potential for an axis of 1-2" from the Black Hills northeastward. Day 2 WPC snow probability of at least 2" is 20-30%
in the Black Hills.

...Cascades and Northern Rockies...
Days 1-3...

An upper low reaches the WA/OR coast this afternoon with a series
of reinforcing shortwave troughs maintaining low pressure over the
Northwest states for much of the next week. Snow levels are
generally 6000ft in the Cascades. A thermal gradient is apparent
over west-central MT with snow levels down to 3000ft east of MT
terrain and around 8000ft in ID and WY. Day 1 snow probs for >6"
are 40-60% in the highest southern WA and OR Cascades. Day 2.5 snow
probs for >6" 30-50% for the Tetons up along the ID/MT border
terrain. Day 3 snow probs for >6" are farther north over the WA
Cascades and north west MT ranges in/near Glacier NP.

For Days 1-3, the probability of significant ice across the CONUS
is less than 10 percent.

Jackson

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sunday, October 25, 2026 18:57:52

FOUS11 KWBC 251857
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
257 PM EDT Sun Oct 25 2026

Valid 00Z Mon Oct 26 2026 - 00Z Thu Oct 29 2026

...Colorado...
Day 1...

Exiting upper low moving through Colorado tonight will bring an
additional few inches to elevations above 9000ft before ending by
12Z Monday.

...Northern Plains...
Days 1-2...

As the upper low over Colorado weakens to a trough overnight, a
surface low will track across Kansas and eastern Nebraska Monday
with enough comma head precip expansion to have some snow bands on
the northwest side of the precip shield. This should intersect with
the Black Hills Monday along with dynamic enough banding for some
snow accumulation in northwestern South Dakota and south-central
North Dakota. Temperatures are marginal, and the trend was been a
bit slower such that most snow would fall between 18-00Z when it is
less likely to stick. However, any snow that falls before sunrise
or after sunset Monday would have a better chance of accumulating.
Most likely forecast is for a broad swath of T-0.5" snow with some
potential for an axis of 1-2" from the Black Hills northeastward.
WPC probabilities of at least 4 inches of snow are about 10% in
over parts of central SD and around 20-40% for at least 2" of snow.

...Cascades and Northern Rockies...
Days 1-3...

A modestly robust upper low just west of the WA coast this evening
will move inland into the northern Great Basin on Monday with trailing/reinforcing shortwave troughs maintaining low pressure
over the Northwest states for much of the week. Higher snow levels
above 5000-8000ft ahead of the initial upper low Monday will lower
to 4000-5500ft or so by Wednesday as another stronger upper low
dips in from the BC coast, which could push snow levels to around
3500ft over the WA Cascades. WPC probabilities for at least 8
inches of snow over the next three days are >50% above about
5000-6000ft from north to south along the Cascades from WA to OR,
and about 5000ft over Idaho and western MT. Over northwestern WY,
snow levels will be higher and significant snow will be above
9000ft.

By Wednesday, snow will likely start to fall at some of the pass
levels including Washington, Stevens, and also Snoqualmie Passes.
The probability of at least 2 inches of snow at Snoqualmie Pass
through 00Z Thu is about 70%.

For Days 1-3, the probability of significant ice across the CONUS
is less than 10 percent.

Fracasso

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Monday, October 26, 2026 08:34:56

FOUS11 KWBC 260834
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
434 AM EDT Mon Oct 26 2026

Valid 12Z Mon Oct 26 2026 - 12Z Thu Oct 29 2026

...Northern Plains...
Days 1-2...

As the upper low over Colorado weakens to a trough overnight, a
surface low will track across Kansas and eastern Nebraska Monday
with enough comma head precip expansion to have some snow bands on
the northwest side of the precip shield. This should intersect with
the Black Hills Monday along with dynamic enough banding for some
snow accumulation in northwestern South Dakota and south-central
North Dakota. Temperatures are marginal, and the trend was been a
bit slower such that most snow would fall between 18-00Z when it is
less likely to stick. However, any snow that falls before sunrise
or after sunset Monday would have a better chance of accumulating.
Most likely forecast is for a broad swath of T-0.5" snow with some
potential for an axis of 1-2" from the Black Hills northeastward.
WPC probabilities of at least 4 inches of snow are about 10% in
over parts of central SD and around 20-40% for at least 2" of snow.

...Cascades and Northern Rockies...
Days 1-3...

An active pattern for the Northwest U.S. is on tap for this week as
a series of low pressure systems and shortwave troughs comes down
the British Columbia coast and tracks over the Pacific Northwest
through at least the work week. Snow levels on the Cascades
generally decrease over the next few days with values around 5000ft
through tonight, dropping to around 4000ft Tuesday night and
3000ft on Wednesday night. Light to moderate precip occurs off and
on. Day 1 snow probs for >6" are 50-80% for the higher Oregon
Cascades with Days 2 and 3 shifted farther north to the Washington
Cascades with probs for >6" 50-80% both days with snow down to
Snoqualmie Pass level for Wednesday.

Mountain snow lingers over the northern Rockies with warm air
advection raising snow levels today over western Wyoming up
through southwest Montana into the 8000ft range. Day 1 snow probs
for >6" are 30-60% for the Tetons up through the Beartooth range.
Snow levels then drop to around 5000ft early Tuesday where they'll
linger through the middle of the week with the precip focus
shifting north by Wednesday. Day 2 and 3 snow probs for >6" are
50-80% for northwest Montana and northern Idaho ranges.

For Days 1-3, the probability of significant ice across the CONUS
is less than 10 percent.

Jackson

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Monday, October 26, 2026 18:20:24

FOUS11 KWBC 261820
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
220 PM EDT Mon Oct 26 2026

Valid 00Z Tue Oct 27 2026 - 00Z Fri Oct 30 2026

...Dakotas into northern Minnesota...
Day 1...

A compact shortwave and weak surface low will continue to produce
dynamically forced precipitation from portions of north-central SD
and south-central ND into northern MN tonight into Tuesday morning.
Despite marginal surface temperatures, enough dynamic cooling will
be present directly underneath the potent shortwave aloft to
support periods of mainly light to briefly moderate snow. Any
accumulations of a coating up to an inch (or two at most) should
mainly be confined to colder, elevated, or grassy surfaces, with
limited impacts to paved surfaces. As a result, WSSI-P
probabilities for minor impacts (winter driving conditions or a few inconveniences to daily life) remain low at 20% or less.

...Cascades and Northern Rockies...
Days 1-3...

An active and unsettled pattern is on tap for the Northwest U.S.
this week as a series of low pressure systems and shortwave troughs
dig southward along the British Columbia coast and track over the
Pacific Northwest. Snow levels across the Cascades will
progressively lower with time, starting around 5000ft tonight,
dropping to around 4000ft Tuesday night, then lowering to around
3000ft Wednesday night into Thursday. Snow in the Cascades will
initially be showery and intermittent with mostly light to moderate
intensity outside of heavier bursts. However, snow should become
steadier and heavier Tuesday night into Wednesday before turning
showery again Wednesday night into Thursday. The Probabilistic
Precipitation Portal (PPP) shows high probabilities (>70%) for
accumulations >8" through Thursday, and >50% probabilities for

12", greatest in the higher elevations of the Washington Cascades.

The WSSI-P shows 40-60% probabilities for minor impacts and winter
driving conditions down to Snoqualmie and Stevens passes.

Meanwhile, periods of mountain snow will continue over the
northern Rockies through Thursday with snow levels falling and then
generally hovering between 4000ft and 6000ft (lowest north,
highest south). Precipitation will initially be focused across the
high elevations of eastern ID, northwest WY, and southwest MT
before shifting northward to the northern ID and northwest MT
ranges (including the Lewis Range and Glacier National Park) by
Wednesday. Increasing large scale forcing for ascent downstream of
the disturbances pivoting across the Pacific Northwest combined
with increasing low-level northeasterly/easterly upslope flow south
of an encroaching surface high will result in some lengthier
periods of snow with intensity that could become heavy at times.
The PPP shows >50% probabilities for accumulations >8" across the
high elevations of eastern ID, southwest MT, and northwest WY...
and >50% for accumulations >12" in the high elevations of northern
ID and northwest MT. While the greatest snow accumulations will
likely stay above pass level, the latest WSSI-P still shows ~20-40% probabilities of minor impacts and winter driving conditions at
various passes in ID and MT.

The probability of significant ice across the CONUS is less than
10 percent.

Miller

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tuesday, October 27, 2026 08:41:16

FOUS11 KWBC 270840
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
440 AM EDT Tue Oct 27 2026

Valid 12Z Tue Oct 27 2026 - 12Z Fri Oct 30 2026

...Cascades and Northern Rockies...
Days 1-3...

Mountain snows continue for the Northwest U.S. through midweek
with shortwave troughs impacting the region today followed by a
slow moving low dropping from southern BC to western Washington
tonight through Thursday. Cascades snow levels currently around
5000ft tonight, drop to around 4000ft tonight, then lower to 3000ft
in Washington on Wednesday under the upper low. WPC snow probs for

6" are 50-80% on the Washington Cascades and 30-60% for the

highest Oregon Cascades for both Days 1 and 2.

Meanwhile, periods of mountain snow will continue over northwestern
Montana and northern Idaho terrain through Wednesday night with
5000ft snow levels lingering through tonight before dipping to
4000ft Wednesday. Day 1 and 2 WPC snow probs for >6" are 30-70% for
terrain north from the Bitterroots.

The slow moving low drifts off the WA coast Thursday with precip
rates tapering off for much of the Northwest.

The probability of significant ice across the CONUS is less than
10 percent.

Jackson

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tuesday, October 27, 2026 18:50:52

FOUS11 KWBC 271850
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
250 PM EDT Tue Oct 27 2026

Valid 00Z Wed Oct 28 2026 - 00Z Sat Oct 31 2026

...Cascades and Northern Rockies...
Days 1-3...

An amplifying upper low will organize west of British Columbia and
then dig slowly southward, reaching to a latitude near the
Oregon/Washington border by the end of the forecast period. As
heights fall to around the 10th percentile (NAEFS), spokes of
vorticity will shed eastward providing ascent from the Pacific
Northwest into the Northern Rockies. These waves of vorticity will
complement mid-level divergence occurring downstream of this upper
low, and a weak stationary front draped west to east near the
Canadian border, leading to waves of snow all 3 days of the
forecast period.

The heaviest snowfall is likely across the Cascades D1 and D2 when
mid-level flow orthogonal to the Crest. PWs will be near normal,
but impressive and persistent omega driven by upslope noted via
regional cross sections will provide ascent for heavy snow,
especially in the upwind terrain Wednesday and Thursday,. This will
lead to snowfall rates that may eclipse 1"/hr at times, especially
above 4000 ft, but with some lowering as the upper low meanders
just off the WA/OR coast. Total snowfall is likely (>60% chance) to
be above 12" in the higher elevations, but impactful pass-level
snow accumulation exceeding 4" is possible (10% chance at
Snoqualmie, 60% chance at Stevens) through the event leading to
challenging travel.

Farther east, periods of snow will also occur across the Northern
Rockies from the Okanogan Highlands through the area around Glacier
National Park. Snow levels will slowly drop through the period from
around 5000 ft D1 to as low as 3500 ft late D2, but the heaviest
accumulations are likely D1 to D1.5 during the period of lowering
snow levels. With modest overall temperatures, precipitation may
mix at times even up to 5000 ft which is reflected by positive snow
depth change that is much less than accumulated snowfall from the
global guidance. This indicates low SLR snowfall, however, leading
to impacts from snow load as reflected by WSSI-P that is as high as
20-30% for moderate impacts.

The probability of significant ice across the CONUS is less than
10 percent.

Weiss

$$
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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wednesday, October 28, 2026 08:47:02

FOUS11 KWBC 280846
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
446 AM EDT Wed Oct 28 2026

Valid 12Z Wed Oct 28 2026 - 12Z Sat Oct 31 2026

...Northern Cascades and Northern Rockies...
Day 1...

A low pressure system shifting south across Vancouver Island today
continues to promote heavy snow over the WA and northern OR
Cascades into this evening. The ample moisture streams inland as
well, bringing heavy snow to terrain in northern Idaho and
northwest Montana through tonight. The low stalls just off western
Washington into Saturday with a combo of mostly dry slot and brief
shortwave trough activity over the Northwest through that time.

Snow levels are at or below Washington Cascades passes today,
generally around 3500ft and 4500ft down through the central Oregon
Cascades. The heaviest rates are early this morning as inferred by
regional NEXRAD depicting bright banded areas of precip pushing
east of Seattle to Portland as of 0830Z. Both the 00Z HREF and 06Z SPC
REFS depictions of mean snowfall rates support 1-2"/hr rates until
about 16Z when mean rates dip to 1"/hr or less on the higher
Cascades. Day 1 WPC snow probs for >6" are 30-80% above pass level
with 20-40% probs for >4" at pass level in the Washington Cascades.

The heaviest snow rates occur on the far northern Rockies
(generally north from the Bitterroots) today from around 16Z to 22Z
per both the recent HREF and REFS mean snowfall rate products with
rates generally 0.5 to 1.5"/hr. Day 1 WPC snow probs for >6" are
40-80% in this terrain above the snow levels around 4500ft.

As noted above, shortwave activity should product additional snows
over these areas into Saturday. The Day 2.5 snow probs for >4" are
20-40% in the North Washington Cascades where snow levels should be
around 3000ft.

The probability of significant ice across the CONUS is less than
10 percent.

Jackson

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wednesday, October 28, 2026 17:51:14

FOUS11 KWBC 281750
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
150 PM EDT Wed Oct 28 2026

Valid 00Z Thu Oct 29 2026 - 00Z Sun Nov 01 2026

...Northern Cascades and Northern Rockies...
Days 1-2...

Closed mid-level low will spin just offshore the WA coast into
Friday, with modest downstream divergence and shedding spokes of
vorticity driving ascent into the Pacific and Interior Northwest
from the Olympics through the Northern Rockies. Although moisture
will spread eastward within pinched flow SE of this mid-level
feature, PWs will be generally near normal, and the most intense
ascent (through synoptic forcing and upslope enhancement) will be
waning early D1, so total additional snowfall is likely to be
modest. Waves of precipitation falling as snow above generally 4000
ft will continue into at least Friday, but with intensity waning
outside of pockets of convectively-enhanced precipitation driven by
mid-level instability and steepening lapse rates beneath the upper
low. Still, additional snowfall is likely to be modest, as
reflected by just small pockets of 50%+ probabilities of 4 inches
or more in the highest Olympics, northern Cascades, and Northern
Rockies in the vicinity of Glacier NP.

...Sierra into the Four Corners...
Day 3...

Although most of the winter precipitation associated with the next
system will occur beyond this current forecast period (mostly D4+),
some high-elevation snow will spread across the Sierra and into the
San Juans above 9000 ft before 00Z Sunday. This will be associated
with an impressive wave of low pressure lifting northeast from the
eastern Pacific with anomalous PW/IVT surging into the Southwest.
While snowfall D3 will likely be minimal, the extremely moist
column will support anomalously low SLR with a 10-30% chance of at
least minor impacts due to snow load developing before expanding
into D4.

The probability of significant ice across the CONUS is less than
10 percent.

Weiss

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thursday, October 29, 2026 06:26:30

FOUS11 KWBC 290626
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
226 AM EDT Thu Oct 29 2026

Valid 12Z Thu Oct 29 2026 - 12Z Sun Nov 01 2026

...Sierra Nevada into the Intermountain West & Four Corners...
Day 3...

Very deep upper level trough (<10th climatological percentile per
the NAEFS) along with a southern shortwave ejecting out of the
subtropical Eastern Pacific will interact along the West Coast by
late Saturday into Sunday to surge ample moisture into the
Southwest and Intermountain West. Snow levels are expected to
remain rather high ahead of this system, starting out above
9,000-10,000 feet across the Southwest, Great Basin and
central/southern Rockies before levels begin to drop around 8,000
feet and much lower across the northern Sierra and northern CA into
the Northwest underneath the upper trough early Sunday, but these
colder areas are expected to remain outside of the primary
moisture transport. Additional mountain snow and eventually
lowering snow levels are anticipated into the Day 4 period (by
Monday morning).

In general, the best chances (40-70%) for snowfall totals greater
than 6 inches through early Sunday are anticipated to remain across
the high terrain of the Sierra Nevada (above 9000 feet) and
Sawtooths of ID (above 8500 feet), with heavier accumulations not
expected across the mountainous terrain of UT and the
central/northern Rockies until later into the weekend and early
next week.

The probability of significant ice across the CONUS is less than
10 percent.

Snell

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thursday, October 29, 2026 18:11:04

FOUS11 KWBC 291810
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
210 PM EDT Thu Oct 29 2026

Valid 00Z Fri Oct 30 2026 - 00Z Mon Nov 02 2026

...Sierra Nevada into the Intermountain West & Four Corners...
Day 2-3...

An impressive full-latitude upper trough, represented by NAEFS
height anomalies falling below the 10th percentile along most of
the Pacific Coast, will gradually pivot eastward into early next
week. Downstream of this deepening trough, a subtropical jet streak
will amplify and surge northeast, with downstream diffluence
overlapping with intensifying mid-level divergence to produce
robust deep layer ascent across the Southwest and Intermountain
West this weekend.

Moisture embedded within a pronounced IVT plume (peak IVT above 500
kg/m/s from the West-WRF centered over the Southwest) will lift
into the increasing ascent, resulting in widespread precipitation
D2 and D3 from southern CA through the Northern Rockies. The WAA
accompanying the IVT will push snow levels to 9000-10000 ft across
the Intermountain West (slightly lower 8000 ft in ID/MT), keeping
most of the precipitation rain. However, accumulating snow is
likely in the higher elevations, with periodic lowering of snow
levels to 7000-9000 ft (near the NBM 10th percentile, varying with
location) thanks to steep lapse rates aloft and some enhanced
ascent through 700-600mb fgen and upslope forcing.

Some light snow is possible D1, but in general accumulating snow
will occur primarily on D2 and D3. During this time, the higher
elevations of the Sierra will be favored for the heaviest
accumulation, with a 60% chance of at least 12 inches, with local
maxima approaching 2 feet. Additional heavy snow exceeding 6 inches
is likely (>60%) across the higher elevations of the Sawtooth of
ID, the Uintas of UT, and the San Juans of CO, where locally 12+"
is possible. All of this snow will likely be comprised of less- than-climatological SLR, leading to substantial snow load impacts
(20-50% chance of at least moderate impacts due to snow load from
the WSSI-P.

The probability of significant ice across the CONUS is less than 10
percent.

Weiss

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Friday, October 30, 2026 06:39:40

FOUS11 KWBC 300639
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
239 AM EDT Fri Oct 30 2026

Valid 12Z Fri Oct 30 2026 - 12Z Mon Nov 02 2026

...Sierra Nevada into the Intermountain West & Four Corners...
Days 1-3...

An impressive full-latitude upper trough, represented by NAEFS
height anomalies falling below the 10th percentile along most of
the Pacific Coast, will gradually pivot eastward into early next
week over the Intermountain West and Rockies. Downstream of this
deepening trough, a subtropical jet streak will amplify and surge
northeast, with downstream diffluence overlapping with intensifying
mid-level divergence to produce robust deep layer ascent across
the Southwest and Intermountain West this weekend.

Moisture embedded within a pronounced IVT plume (peak IVT above 500
kg/m/s from the West-WRF centered over the Southwest) will lift
into the increasing ascent, resulting in widespread precipitation,
most prominent on D2 and D3, from southern CA through the Northern
Rockies. The WAA accompanying the IVT will push snow levels to
9000-10000 ft across the Intermountain West (slightly lower-8000
ft in ID/MT and higher-11000 ft in CO), keeping most of the
precipitation rain. However, accumulating snow is likely in the
higher elevations, with periodic lowering of snow levels to
7000-9000 ft (near the NBM 10th percentile, varying with location)
thanks to steep lapse rates aloft and some enhanced ascent through
700-600mb fgen and upslope forcing. As the pronounced trough
crosses over the Rockies by the end of D3, snow levels will
gradually fall below 7000-8000ft across the Northern Rockies and
Great Basin, but coinciding with drying northwesterly mid-upper-
level flow early Monday.

Some light snow is possible D1, but in general accumulating snow
will occur primarily on D2 and D3. During this time, the higher
elevations of the Sierra will be favored for the heaviest
accumulation, with a 60% chance of at least 12 inches, with local
maxima approaching 2 feet. Additional heavy snow exceeding 6 inches
is likely (>60%) across the higher elevations of the Sawtooth of
ID, the Uintas of UT, Wind River Range of WY, and the San Juans of
CO, where locally 12+" is possible. All of this snow will likely
be comprised of less- than-climatological SLR, leading to
substantial snow load impacts (50-90% chances of at least moderate
impacts due to snow load from the WSSI-P across the San Juans).

The probability of significant ice across the CONUS is less than 10
percent.

Weiss/Snell

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Friday, October 30, 2026 18:25:50

FOUS11 KWBC 301825
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
225 PM EDT Fri Oct 30 2026

Valid 00Z Sat Oct 31 2026 - 00Z Tue Nov 03 2026

...Sierra Nevada into the Intermountain West & Four Corners...
Days 1-3...

A full latitude trough with dual embedded closed mid-level lows
will haunt the western CONUS, causing increasingly unsettled
weather into early next week with rain and high elevation snowfall.

A closed mid-level low centered off the OR/WA coast will elongated
southward through Saturday, amplifying the accompanying longwave
trough along the Pacific Coast. At the same time, a secondary
shortwave lifting northeast out of the eastern tropical Pacific
will eject northeast, and these two impulses will phase over the
Southwest and then lift across the Great Basin, reaching the
Central Rockies by the end of the forecast period. Downstream
divergence combined with periods of impressive PVA will drive
large-scale ascent, aided by locally impressive fgen and upslope
flow.

The airmass accompanying this system will become increasingly moist
thanks to impressive IVT surging northeast downstream of this
eastward translating upper trough. The West-WRF IVT probabilities
peak above 90% for 250 kg/m/s, and although the core of this IVT
stays south across CA/AZ, it represents an impressive moisture
plume that will flood across the region beginning Saturday evening
and then persisting as it shifts eastward through Monday. As is
typical with tropical IVT, the accompanying WAA will push snow
levels to as high as 8000-9000 ft in the Great Basin/Sierra, and as
high as 11,000 ft farther east into the Central Rockies, and
although snow levels will slowly fall by early next week, the
heaviest precipitation will exist within this elevated snow levels,
and despite elevated instability and steep lapse rates, most snow
accumulation should remain above 8000-9000 ft in all terrain.

Still, impactful snow is likely across these higher elevations,
especially within the Sierra, Uintas, San Juans, and Sawtooth where probabilities for at least 12" of snow exceed 80%, and locally as
much as 2 feet of snow may fall. This snow will feature generally lower-than-climo SLR to create snow load impacts, and the WSSI-P
indicates a 50-70% chance of at least moderate impacts in the San
Juans, 20-40% chance across the other higher elevations. Although
most of this will be above pass level, some locally hazardous
travel at the higher passes is expected.

The probability of significant ice across the CONUS is less than 10
percent.

Weiss

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, October 31, 2026 06:41:16

FOUS11 KWBC 310640
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
240 AM EDT Sat Oct 31 2026

Valid 12Z Sat Oct 31 2026 - 12Z Tue Nov 03 2026

...Sierra Nevada into the Intermountain West & Rockies...
Days 1-3...

A full latitude trough with dual embedded closed mid-level lows
will haunt the western CONUS, causing increasingly unsettled
weather into early next week with rain and high elevation snowfall.

A closed mid-level low centered off the OR/WA coast will elongated
southward through Saturday, amplifying the accompanying longwave
trough along the Pacific Coast. At the same time, a secondary
shortwave lifting northeast out of the eastern tropical Pacific
will eject northeast, and these two impulses will phase over the
Southwest and then lift across the Great Basin, reaching the
Central Rockies by Monday. Downstream divergence combined with
periods of impressive PVA will drive large-scale ascent, aided by
locally impressive fgen and upslope flow.

The airmass accompanying this system will become increasingly moist
thanks to impressive IVT surging northeast downstream of this
eastward translating upper trough. The West-WRF IVT probabilities
peak above 90% for 250 kg/m/s, and although the core of this IVT
stays south across CA/AZ, it represents an impressive moisture
plume that will flood across the region beginning Saturday evening
and then persisting as it shifts eastward through Monday. As is
typical with tropical IVT, the accompanying WAA will push snow
levels to as high as 8000-9000 ft in the Great Basin/Sierra, and as
high as 11,000 ft farther east into the Central Rockies, and
although snow levels will slowly fall by early next week, the
heaviest precipitation will exist within this elevated snow levels,
and despite elevated instability and steep lapse rates, most snow
accumulation should remain above 8000-9000 ft in all terrain.
Precipitation is expected to end by Sunday night across the Sierra,
followed by Monday across the Great Basin/Northern Rockies and
Central Rockies by Monday night.

Still, impactful snow is likely across these higher elevations,
especially within the Sierra, Uintas, San Juans, and Sawtooth where
NBM probabilities for at least 12" of snow exceed 70%, and locally
as much as 2 feet of snow may fall. This snow will feature
generally lower-than-climo SLR to create snow load impacts, and the
WSSI-P indicates a 70-90% chance of at least moderate impacts in
the San Juans, 20-40% chance across the other higher elevations.
This may lead to isolated areas of tree damage in the San Juans,
where heavy snow may fall just below the tree line (around 11,000
ft). Although most of this will be above pass level, some locally
hazardous travel at the higher passes is expected as well.

The probability of significant ice across the CONUS is less than 10
percent.

Weiss/Snell

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, October 31, 2026 18:15:06

FOUS11 KWBC 311814
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
214 PM EDT Sat Oct 31 2026

Valid 00Z Sun Nov 01 2026 - 00Z Wed Nov 04 2026

...Sierra Nevada into the Intermountain West & Rockies...
Days 1-3...

An increasingly amplified mid-level pattern across the western and
central CONUS will bring widespread unsettled weather from the
Desert Southwest, through the Intermountain West, and into the High
Plains. High elevation impactful snowfall is likely across the
higher terrain, with periods of lesser lower-elevation snows also
possible.

An impressive full latitude trough will be deepening off the
Pacific Coast to being to the period, and this trough will
gradually translate eastward into the Great Basin before closing
off Sunday evening. This trough will continue to push to the east
into the middle of next week, but there is greater-than-typical
uncertainty with the evolution and phasing of multiple mid-level
impulses across the Central/Northern Plains by Tuesday.

While most of the precipitation is expected to be rain, heavy
mountain snow is likely, especially above 9000 ft. The primary
mechanism for this is downstream advection of impressive IVT
exceeding 500 kg/m/s surging from the tropical Pacific and as far
east as the Central Plains. This intense moist advection, reflected
by NAEFS ensemble PW above anything previously measured for this
timeframe in the CFSR database, will expand heavy precipitation
across a large portion of the region. However, the accompanying WAA
will keep snow levels elevated as noted above, limiting significant accumulations to above 9000 ft across the Sierra, Unitas, San
Juans, higher CO Rockies, Sawtooth, and Wind Rivers. However, in
these areas, snow will be impactful due to low SLR leading to
moderate to locally major (major in the San Juans) impacts from
snow load forecast via the WSSI-P.

The heaviest accumulations are likely in the Sierra, San Juans, and
Uintas, where there is a greater than 90% chance for at least 12
inches of snow, with locally 2 feet possible. Farther north, the
higher elevations of the Big Horns and Wind Rivers and Sawtooth
have a 60% chance for at least 12 inches of snow. While most of the
snow should remain at the highest elevations, as the low wraps up
and some cold air pulls into the system within increasing
deformation across MT/WY Sunday night through Monday night some
lower elevation mixing may occur, but notable accumulations below
6000 ft are not currently expected.

The probability of significant ice across the CONUS is less than 10
percent.

Weiss

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sunday, November 01, 2026 07:22:58

FOUS11 KWBC 010722
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
222 AM EST Sun Nov 1 2026

Valid 12Z Sun Nov 01 2026 - 12Z Wed Nov 04 2026

...Sierra Nevada into the Intermountain West & Rockies...
Days 1-2...

An increasingly amplified mid-level pattern across the western and
central CONUS will bring widespread unsettled weather from the
Desert Southwest, through the Intermountain West, and into the High
Plains over the next few days. High elevation impactful snowfall
is likely across the higher terrain, with periods of lesser lower-
elevation snows also possible.

An impressive full latitude trough will be moving inland along the
West Coast to begin the period, and this trough will gradually
translate eastward into the Great Basin before closing off Sunday
evening. This trough will continue to push to the east through
early this week, with precipitation ending across the Rockies
Tuesday morning.

While most of the precipitation is expected to be rain, heavy
mountain snow is likely, especially above 9000 ft. The primary
mechanism for this is downstream advection of impressive IVT
exceeding 500 kg/m/s surging from the tropical Pacific and as far
east as the Central Plains. This intense moist advection, reflected
by NAEFS ensemble PW above anything previously measured for this
timeframe in the CFSR database, will further expand heavy
precipitation across a large portion of the region. Coverage and
intensity of this precipitation is expected to peak this afternoon
through early Monday morning across the Southwest, Central Great
Basin, and Rockies. However, the accompanying WAA will also keep
snow levels elevated as noted above, limiting significant
accumulations to above 9000 ft across the Sierra, Unitas, San
Juans, higher CO Rockies, Sawtooth, and Wind Rivers. However, in
these areas, snow will be impactful due to low SLR leading to
moderate to locally major (major in the San Juans) impacts from
snow load forecast via the WSSI-P.

The heaviest additional accumulations are likely in the San
Juans, Uintas, Wind River Range, and CO Elk Mts, where there is a
greater than 50% chance for at least 12 inches of snow, with
locally 2 feet storm total possible. Farther north, the higher
elevations of the Big Horns also have a 50% chance for at least 8
inches of snow. While most of the snow should remain at the highest
elevations, as the low wraps up and some cold air pulls into the
system within increasing deformation across MT/WY Sunday night
through Monday night some lower elevation mixing may occur, but
notable accumulations below 6000 ft are not currently expected.

The probability of significant ice across the CONUS is less than 10
percent.

Weiss/Snell

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sunday, November 01, 2026 19:12:04

FOUS11 KWBC 011911
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
211 PM EST Sun Nov 1 2026

Valid 00Z Mon Nov 02 2026 - 00Z Thu Nov 05 2026

...Sierra Nevada into the Intermountain West & Rockies...
Days 1-2...

An active period of unsettled weather begins today across the
western CONUS as anomalous moisture surges northeast from the
tropical Pacific. The primary mechanism driving this surge of
moisture is an elongated and amplifying longwave trough shifting
into the Intermountain West, with embedded shortwaves and lobes of
vorticity swinging through its base. This amplified trough, with
500mb heights below the 10th percentile of the CFSR database, will
steadily translate eastward, and combine with a modest but
favorable placed subtropical jet streak to drive large scale deep
layer ascent from the Sierra eastward through the Central Plains.

Downstream of this trough, an extreme moisture surge will push IVT
across a large breadth of the region to above the maximum of the
CFSR climatology, which will support widespread precipitation in
response to the impressive ascent overlapping this moist conveyor.
While the accompanying WAA will keep snow levels elevated, around 8000-9000
ft within the heavier precipitation corridor, some locally lower
snow levels are possible where fgen/upslope flow can drag colder
air down within steep lapse rates beneath the upper trough. Still,
the most significant snowfall is expected above 9000 ft and the
probability for an additional 12+ inches of snow is above 70% in
the San Juans. Big Horns, and highest CO Rockies, with lower
amounts expected elsewhere above 6000 ft across much of the
Intermountain West. Since this snow is likely to feature sub-climo
SLR, snow load impacts are expected in these areas.

As the trough pushes east a surface low is likely to deepen in the
lee of the Rockies and then rapidly intensify during Monday as it
lifts into the Upper Midwest/Great Lakes. This low will produce
only rain for most areas, however, depending on the exact evolution
of the associated upper low, a pivoting axis of deformation may
cross the Dakotas and into WY/CO Monday night and Tuesday. Where
precipitation falls heavily enough, some mixed rain and snow is
possible, leading to light accumulations of snow as far east as the
Black Hills of SD.

The probability of significant ice across the CONUS is less than 10
percent.

Weiss

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Monday, November 02, 2026 07:25:26

FOUS11 KWBC 020725
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
225 AM EST Mon Nov 2 2026

Valid 12Z Mon Nov 02 2026 - 12Z Thu Nov 05 2026

...Rockies...
Day 1...

Sharp upper trough centered over the Rockies to start the forecast
period and associated influx of anomalous tropical Pacific
moisture will be pushing into the central U.S. today, with
precipitation and mostly high elevation snowfall ending across the
Great Basin and Rockies by early Tuesday.

Snow levels will gradually fall through the D1 forecast period, but
at the same time as the column begins to dry as flow becomes
northwesterly behind the exiting upper trough. These levels will
start out this morning around 6000-8000ft across the central Great
Basin and northern Rockies, with higher snow levels across the
central Rockies around 9000-11000ft. By Monday night these are
expected to lower to a more uniform 6000-8000ft (lowest across the
northern Rockies). Additional snowfall amounts are expected to be
mostly light below 8000-9000ft. Probabilities for at least an
additional 8 inches of snow are greatest (40-80%) across the San
Juans, Sawatch, and Medicine Bow Mts of CO. The Laramie and Bighorn
Mts as well as the Black Hills also have the potential for
moderate snowfall amounts, with 40-80% probabilities for at least 6
inches of snow through 12Z Tuesday. Gusty winds are also expected
to accompany snowfall across some of the WY mountain ranges and
adjacent High Plains into the Black Hills, which could lead to
brief periods of low visibility from blowing snow into early
Tuesday.

The probability of significant ice across the CONUS is less than 10
percent.

Snell

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Monday, November 02, 2026 20:15:02

FOUS11 KWBC 022014
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
314 PM EST Mon Nov 2 2026

Valid 00Z Tue Nov 03 2026 - 00Z Fri Nov 06 2026

...Central Rockies...
Day 1...

As of 20Z...a mid-level low is apparent in water vapor imagery as
over the eastern CO/NM border with a reinforcing shortwave trough
over the ID/WY border. Patchy mountain snow is between these
features with snow levels around 7000ft in WY and 8000ft in CO. The
reinforcing trough plunges south-southeast through tonight,
reaching northeast NM by 12Z Tuesday. Snow levels drop about a
thousand feet overnight before snow tapers off. Day 1 snow probs
for >4" additional are generally 30-50% for the highest CO and
southern WY ranges.
In addition, upper troughing in the lee of the Rockies/central High
Plains should see some snow bands late tonight (on the far end of
a strung out comma head from surface lows over the eastern Plains)
with snow levels dropping to around 5500ft. Day 1 snow probs for

2" are 20-40% in parts of southeast WY and the Black Hills with

some probs for >1" into the Neb Panhandle. Precip quickly shifts
east to the lower Plains early Tuesday, so the snows taper off by
then.

Days 2/3...

The base of a trough currently well off Northern California
continues shifting east, tracking from northern Nevada Wednesday
to southern CO by Wednesday evening. This clipper type wave brings
mainly light mountain snows ahead of this track with snow levels
generally 6000-7000ft. Day 2.5 snow probs for >4" are 20-40% in
higher ranges of central CO, including max 60% probs in the Sawatch
and Mosquito Ranges.

The probability of significant ice across the CONUS is less than 10
percent.

Jackson

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tuesday, November 03, 2026 07:40:04

FOUS11 KWBC 030739
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
239 AM EST Tue Nov 3 2026

Valid 12Z Tue Nov 03 2026 - 12Z Fri Nov 06 2026

...Central Rockies...
Day 2...

Potent shortwave currently off the coast of Northern California is
expected to track nearly due west across the central Great Basin by
early Wednesday, before crossing the Central Rockies late Wednesday
and interacting along the southwestern periphery of a deeper cutoff
upper low anchored across the Upper Midwest. Decent ascent just to
the north of this shortwave crossing the West as well as a 110kt
associated jet streak, will allow for an area of precipitation to
be mostly light across UT and CO on Wednesday, but with embedded
heavier showers where lift is greatest along favorable high
terrain. Snow levels will generally be around 7000-8000ft, but
dropping to around 6000ft within heavier precipitation and dynamic
cooling. Overall, snowfall amounts are expected to remain minor for
the Wasatch/Uinta Mts of UT and CO Rockies. Greatest probabilities
(30-60%) for at least 6 inches of snow is located across the
Sawatch/Mosquito Ranges into the northern Sangre de Cristo Mts of
CO and at higher elevations above 11000ft.

The probability of significant ice across the CONUS is less than 10
percent.

Snell

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tuesday, November 03, 2026 20:01:04

FOUS11 KWBC 032000
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Tue Nov 3 2026

Valid 00Z Wed Nov 04 2026 - 00Z Sat Nov 07 2026

...Central Rockies...
Days 1-2...

A closed 500mb low tracking east out of the Great Basin will reach
the Central Rockies Wednesday afternoon, bringing an influx of
anomalous moisture to the region. ECMWF guidance shows PWs topping
the 90th climatological percentile traversing the Central Rockies
Wednesday night. The region also lies beneath the divergent left-
exit region of a ~110kt 250mb jet streak that will support enhanced
upper-level divergence. In addition, 700mb winds in lee of the CO
Rockies will gradually increase out of the east as the 700mb low
tracks over central CO Wednesday afternoon, fostering enhanced
upslope flow along the Front Range. The heaviest snowfall is
likely to occur as the 700mb low passes through early Wednesday
evening. Snowfall rates >1"/hr in the Sawatch/Mosquito ranges are
likely (>70%) and could even surpass 2"/hr at times. The 00-06Z
Thursday time period is likely to produce snowfall totals >8" at
elevations above 11,000ft in central CO. The closed low will open
up into a positively-tilted upper trough early Thursday morning
and snowfall concludes before sunrise Thursday. The PPP shows
moderate-to-high chances (50-70%) for snowfall totals >6" in the CO
mountain ranges above 10,000ft. The peaks of the Sawatch and
Mosquito Ranges do contain low chances (10-30%) for localized
snowfall totals >12". The WSSI-P shows many of these remote
mountain ranges as having moderate chances (40-60%) for Minor
Impacts, which may include some locally hazardous travel conditions
over nearby passes.

The probability of significant ice across the CONUS is less than 10
percent.

Mullinax

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wednesday, November 04, 2026 07:17:40

FOUS11 KWBC 040717
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
217 AM EST Wed Nov 4 2026

Valid 12Z Wed Nov 04 2026 - 12Z Sat Nov 07 2026

...Central Rockies...
Day 1...

A closed 500mb low tracking east out of the Great Basin will reach
the Central Rockies Wednesday afternoon, bringing an influx of
anomalous moisture to the region. ECMWF guidance shows PWs topping
the 90th climatological percentile traversing the Central Rockies
Wednesday night. The region also lies beneath the divergent left-
exit region of a ~110kt 250mb jet streak that will support enhanced
upper-level divergence. In addition, 700mb winds in lee of the CO
Rockies will gradually increase out of the east as the 700mb low
tracks over central CO Wednesday afternoon, fostering enhanced
upslope flow along the Front Range. The heaviest snowfall is
likely to occur as the 700mb low passes through early Wednesday
evening and coming to an end early Thursday.

Snowfall rates >1"/hr in the Sawatch/Mosquito ranges and into the
higher CO Front Range peaks are likely (>70% per the 00Z REFS) and
could even surpass 2"/hr at times (40-70%). The 00-06Z Thursday
time period is likely to produce heaviest snowfall totals >8" at
elevations above 11,000ft in central CO. The closed low will open
up into a positively-tilted upper trough early Thursday morning and
snowfall rapidly concludes before sunrise Thursday. The PPP shows moderate-to-high chances (50-70%) for snowfall totals >8" in the
CO mountain ranges above 10,000ft. The peaks of the Sawatch and
Mosquito Ranges do contain moderate chances (20-50%) for localized
snowfall totals >12". The WSSI-P shows many of these remote
mountain ranges as having 30-70% probabilities for Minor Impacts,
which may include some locally hazardous travel conditions over
nearby passes.

The probability of significant ice across the CONUS is less than 10
percent.

Mullinax/Snell

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thursday, November 05, 2026 06:56:42

FOUS11 KWBC 050656
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
156 AM EST Thu Nov 5 2026

Valid 12Z Thu Nov 05 2026 - 12Z Sun Nov 08 2026

...Upper Peninsula of Michigan...
Day 1...

Departing system sprawled across southeastern Canada will slowly
exit the Great Lakes today, with a trailing vort max diving
southward across Lake Superior this evening. Marginally cold air
will filter in from the north with some lake-enhanced precipitation
on northerly flow. As the 850mb temperature drops below zero and
surface T/Tds fall to the lower 30s, snow will accumulate over
especially the higher terrain away from the relatively milder lake
shore (e.g, Huron Mountains). Expected accumulation is 0.5-2.5" or
so, but the probability of at least 4 inches of snow is 10-20% per
the Probabilistic Precipitation Portal.

The probability of significant ice across the CONUS is less than
10 percent.

Fracasso

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Friday, November 06, 2026 18:57:28

FOUS11 KWBC 061857
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
157 PM EST Fri Nov 6 2026

Valid 00Z Sat Nov 07 2026 - 00Z Tue Nov 10 2026

...Washington Cascades...
Day 2...

A cold front will track through the Pacific Northwest late Saturday
into Sunday. Initially high snow levels at the onset (>6500ft)
will lower to around 4000-5000ft by Sunday morning. Washington
Pass/SR-20 sports moderate-chance probabilities (40-60%) for
snowfall totals >4" and low chances (10-30%) for snowfall totals

6". The latest WSSI does depict Minor Impact potential at

Washington Pass, suggesting that winter driving conditions are
anticipated and motorists should exercise caution while driving
through the Pass Saturday night and into Sunday morning.

The probability of significant ice across the CONUS is less than
10 percent.

Mullinax

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Saturday, November 07, 2026 06:49:10

FOUS11 KWBC 070648
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
148 AM EST Sat Nov 7 2026

Valid 12Z Sat Nov 07 2026 - 12Z Tue Nov 10 2026

...Washington Cascades...
Days 1-2...

A cold front will track through the Pacific Northwest tonight into
Sunday. Initially high snow levels above 7000ft this afternoon
will lower to around 4000-5000ft by Sunday morning as the front
moves from west to east across the region. Washington Pass/SR-20 is
still open and will see a changeover from rain to snow, with at
least couple/few inches of snow expected. The probability of at
least 4 inches of snow there is about 50% and about 30% for at
least 6 inches of snow. Minor impacts are expected -- use caution
while driving.

The probability of significant ice across the CONUS is less than
10 percent.

Fracasso

$$
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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

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