ACUS11 KWNS 162151
SWOMCD
SPC MCD 162150=20
INZ000-ILZ000-162315-

Mesoscale Discussion 1156
NWS Storm Prediction Center Norman OK
0450 PM CDT Tue Jun 16 2026

Areas affected...central IL into west-central and north-central IN

Concerning...Severe Thunderstorm Watch 338...

Valid 162150Z - 162315Z

The severe weather threat for Severe Thunderstorm Watch 338
continues.

SUMMARY...Several supercells will potentially be capable of a threat
for mainly large hail (1 to 1.75 inches in diameter). Localized
severe gusts (55-65 mph) are possible with the stronger cores. A
brief tornado is also possible.

DISCUSSION...Water-vapor imagery shows a potent upper shortwave
trough moving east across the central Great Lakes. Surface analysis
places a cold front from the mid MS Valley arching
east-northeastward into east-central IL and northeastward into the
southern Lake Michigan vicinity. This boundary is serving as the
primary low-level forcing mechanism for storm development late this
afternoon from central IL northeastward towards Lafayette, IN.=20
Ahead of these storms---which contain a few supercell left-right splits---surface conditions of lower 70s deg F temperatures and mid
50s dewpoints are observed.=20

RAP forecast soundings show cold 500-mb temperatures (-16 to -18 deg
C) and gradually veering and strengthening flow with height beneath
80-kt 300 mb westerly flow. As a result, sufficient buoyancy/shear
will continue to support supercells for the next several hours.=20
Large hail appears to be the primary severe hazard, but localized
severe gusts and perhaps a brief tornado are also possible.

..Smith.. 06/16/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6OLAnlvdPNOjA__PBs_A8wmvFM4wWTRkZgaCYBlExrO8zDQMHwrg2y3WPm4dQy3EQ9yMqJItf= 2medUl2-JxDbjCTcAk$ for graphic product...

ATTN...WFO...IWX...IND...LOT...ILX...

LAT...LON 40268572 39618691 39368841 39438886 39638888 39788878
39888806 40098748 40568702 41018674 41158592 41018550
40778538 40268572=20

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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