054
ACUS11 KWNS 121405
SWOMCD
SPC MCD 121404
INZ000-ILZ000-IAZ000-121600-
MESOSCALE DISCUSSION 1949
NWS STORM PREDICTION CENTER NORMAN OK
0904 AM CDT WED AUG 12 2026
AREAS AFFECTED...NORTHERN AND CENTRAL ILLINOIS INTO WESTERN INDIANA
CONCERNING...SEVERE THUNDERSTORM WATCH 574...
VALID 121404Z - 121600Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 574
CONTINUES.
SUMMARY...DAMAGING WINDS WITH GUSTS UP TO 75 MPH ARE EXPECTED TO
CONTINUE WITH AN ONGOING BOW ECHO. THE SEVERE WEATHER THREAT MAY
DEVELOP EAST OF THE WATCH AREA BY 1530Z, LIKELY REQUIRING A NEW
SEVERE THUNDERSTORM WATCH.
DISCUSSION...THE NORTHERN EXTENSION OF AN MCS HAS SUSTAINED A BOWING
STRUCTURE OVER NORTHERN IL WITH AN EASTWARD SYSTEM MOTION OF AROUND
40 KT. AN OUTFLOW BOUNDARY ASSOCIATED WITH AN AREA OF THUNDERSTORMS
FARTHER EAST EXTENDS FROM THE VICINITY OF THE BOW ECHO
SOUTH-SOUTHEAST THROUGH EASTERN IL INTO SOUTHWEST IN. THE PRESENCE
OF THAT BOUNDARY MAY RESULT IN THE MCS TURNING MORE TO THE SOUTHEAST
OVER THE NEXT HOUR TO TWO, FUELED BY A STRONGLY UNSTABLE
ENVIRONMENT, PER THE 12Z DVN SOUNDING.
THE CURRENT DVN VWP IS SAMPLING 35-50 KT WEST-NORTHWESTERLY WINDS IN
THE 1-6 KM LAYER, WHICH ARE ORIENTED LARGELY PERPENDICULAR TO THE
BOW, LIKELY MAINTAINING A ROBUST REAR-INFLOW JET. AS SUCH, DAMAGING
WINDS ARE EXPECTED TO CONTINUE WITH GUSTS UP TO 75 MPH POSSIBLE AS
THE SYSTEM ADVANCES TOWARD NORTHWEST AND WEST-CENTRAL IN.
EXTRAPOLATION OF THE CURRENT MOTION TAKES IT TO THE EASTERN EDGE OF
THE WATCH BY 1530Z, LIKELY REQUIRING AN ADDITIONAL WATCH.
..MEAD.. 08/12/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...IWX...IND...LOT...ILX...DVN...
LAT...LON 41909007 41758803 41268700 40498663 40088648 39578665
39578722 39588774 39848855 40268968 40819028 41499046
41909007
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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