832
ACUS11 KWNS 172351
SWOMCD
SPC MCD 172350
INZ000-ILZ000-180145-
MESOSCALE DISCUSSION 1171
NWS STORM PREDICTION CENTER NORMAN OK
0650 PM CDT WED JUN 17 2026
AREAS AFFECTED...PARTS OF SOUTH-CENTRAL ILLINOIS INTO SOUTHWEST
INDIANA
CONCERNING...TORNADO WATCH 342...344...
VALID 172350Z - 180145Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 342, 344 CONTINUES.
SUMMARY...LARGE HAIL, DAMAGING WINDS, AND THE POTENTIAL FOR A FEW
TORNADOES WILL CONTINUE SPREADING EAST-SOUTHEASTWARD THIS EVENING --
WITHIN TORNADO WATCHES 342/344.
DISCUSSION...A COUPLE SUPERCELLS ARE TRACKING EAST-SOUTHEASTWARD
ALONG THE SOUTHERN FLANK OF A LARGER CONVECTIVE CLUSTER IN
EAST-CENTRAL/SOUTHEAST IL -- WITH ADDITIONAL
DEVELOPMENT/INTENSIFICATION FARTHER WEST IN SOUTH-CENTRAL IL.
DESPITE THE PRESENCE OF VERY STRONG LOW/DEEP-LAYER FLOW/SHEAR
SAMPLED BY THE IND VWP (60 KT LOW-LEVEL JET AND 650-700 M2/S2 0-1 KM
SRH), THESE STORMS ARE TRACKING THROUGH A CORRIDOR OF CONVECTIVELY
PROCESSED AIR FROM EARLIER STORMS. HOWEVER, THE STRONG LOW-LEVEL
MASS RESPONSE ACCOMPANYING AN APPROACHING MIDLEVEL WAVE MAY SUPPORT
ADDITIONAL BOUNDARY-LAYER RECOVERY TOWARD THE INFLOW OF THESE STORMS
DURING THE NEXT FEW HOURS. IF THIS CAN OCCUR, THE ROBUST LOW-LEVEL
SHEAR/STREAMWISE VORTICITY WILL SUPPORT A FEW TORNADOES (SOME OF
WHICH COULD BE STRONG-INTENSE) WITH ANY LONGER-LIVED SUPERCELLS.
VERY LARGE HAIL AND SEVERE WIND GUSTS (75+ MPH) WILL ALSO BE
POSSIBLE WITH THESE STORMS AS THEY CONTINUE EAST-SOUTHEASTWARD.
..WEINMAN.. 06/17/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...IND...ILX...LSX...
LAT...LON 39128678 38888686 38788721 38928769 39158879 39188973
39368996 39648986 39718954 39718833 39598770 39458719
39338688 39128678
MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN
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