497
ACUS11 KWNS 191433
SWOMCD
SPC MCD 191433
ILZ000-WIZ000-191630-
MESOSCALE DISCUSSION 0242
NWS STORM PREDICTION CENTER NORMAN OK
0933 AM CDT WED MAR 19 2025
AREAS AFFECTED...PARTS OF NORTHEASTERN IOWA...NORTHERN
ILLINOIS...SOUTHERN WISCONSIN
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 191433Z - 191630Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...THUNDERSTORMS APPROACHING THE GREATER MILWAUKEE AND
CHICAGO METROPOLITAN AREAS MAY CONTINUE TO POSE A RISK FOR SMALL TO
MARGINALLY SEVERE HAIL BEFORE WEAKENING BY MIDDAY INTO EARLY
AFTERNOON.
DISCUSSION...OBSERVATIONAL DATA INDICATE SOME RECENT INTENSIFICATION
OF THUNDERSTORM ACTIVITY IN AN ARCING NORTHEASTWARD ADVANCING BAND
SPREADING INTO/ACROSS PARTS OF SOUTHERN WISCONSIN AND NORTHERN
ILLINOIS. BASED ON FORECAST SOUNDINGS, THIS CONVECTION IS ROOTED
WITHIN ELEVATED MOISTURE RETURN AND DESTABILIZATION BASED NEAR THE
700 MB LEVEL, BENEATH AN INITIAL SURGE OF COOLING FURTHER ALOFT.
MOST UNSTABLE CAPE MAY BE AS HIGH AS 750+ J/KG ALONG THIS CORRIDOR,
WITH SHEAR WITHIN THE ELEVATED CONVECTIVE LAYER STRONG, WHICH MAY
CONTINUE TO SUPPORT SUB-SEVERE TO MARGINALLY SEVERE HAIL IN STRONGER
CELLS ANOTHER FEW HOURS. INTO MIDDAY DAY, AS ACTIVITY SPREADS
TOWARDS/INTO THE GREATER MILWAUKEE AND CHICAGO VICINITIES, THE
LATEST RAPID REFRESH SUGGESTS THAT THIS CONVECTION WILL PROBABLY
TEND TO WEAKEN AS STORM INFLOW TRENDS LESS UNSTABLE.
..KERR/LEITMAN.. 03/19/2025
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...LOT...MKX...DVN...ARX...
LAT...LON 42819067 43178997 42848824 41578784 40938846 41208911
41958954 42819067
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