412  
ACUS11 KWNS 231952  
SWOMCD  
SPC MCD 231952  
MIZ000-ILZ000-WIZ000-232145-  
 
MESOSCALE DISCUSSION 0507  
NWS STORM PREDICTION CENTER NORMAN OK  
0252 PM CDT TUE APR 23 2024  
 
AREAS AFFECTED...NORTHEAST ILLINOIS AND SOUTHEAST WISCONSIN INTO  
CENTRAL LOWER MICHIGAN  
 
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY  
 
VALID 231952Z - 232145Z  
 
PROBABILITY OF WATCH ISSUANCE...5 PERCENT  
 
SUMMARY...ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE TO  
DEVELOP ACROSS THE GREAT LAKES REGION. A FEW STRONG TO SEVERE STORMS  
ARE POSSIBLE WITH SMALL TO MARGINALLY SEVERE HAIL AND DAMAGING WINDS  
AS THE PRIMARY HAZARDS. COVERAGE OF SEVERE STORMS SHOULD REMAIN  
SUFFICIENTLY LIMITED TO PRECLUDE WATCH ISSUANCE.  
 
DISCUSSION...ISOLATED TO SCATTERED THUNDERSTORMS HAVE BEEN ONGOING  
OVER EASTERN WI, THE UPPER PENINSULA OF MI, AND NORTHERN WI OVER THE  
PAST SEVERAL HOURS WITH MULTIPLE REPORTS OF 0.5 TO 0.75 INCH HAIL  
AND 35-45 KNOT GUSTS NOTED. THIS CONVECTION HAS LARGELY BEEN DRIVEN  
BY ASCENT ALONG AND AHEAD OF A SECONDARY COLD FRONTAL SURGE WHERE A  
COMBINATION OF MODEST DIURNAL WARMING AND COLD TEMPERATURES ALOFT IS  
SUPPORTING MUCAPE BETWEEN 250-500 J/KG. THIS TREND IS EXPECTED TO  
CONTINUE DOWNSTREAM INTO IL/MI AS THE COLD TEMPERATURES ALOFT  
OVERSPREAD THE REGION AND MID/UPPER-LEVEL CLOUD COVER SLOWLY SHIFTS  
SOUTHEAST. BASED ON RECENT OBSERVATIONS AND RAP FORECAST SOUNDINGS,  
AROUND 500 J/KG MUCAPE SHOULD BE FEASIBLE AS SURFACE TEMPERATURES  
WARM INTO THE UPPER 60S. WEAK MID-LEVEL WINDS TO THE NORTH OF A JET  
STREAK OVER IL/IN/OH HAVE LIMITED STORM LONGEVITY/ORGANIZATION THUS  
FAR, BUT DESTABILIZATION CLOSER TO THE STRONGER MID-LEVEL FLOW MAY  
PROMOTE HIGHER, THOUGH STILL SOMEWHAT MEAGER, EFFECTIVE BULK SHEAR  
VALUES BETWEEN 20-25 KNOTS. THIS SHOULD SUPPORT BETTER STORM  
ORGANIZATION WITH A HIGHER POTENTIAL FOR MARGINALLY SEVERE HAIL (0.5  
TO 1.0 INCH) AND LOCALIZED DAMAGING WIND GUSTS (MOST LIKELY BETWEEN  
40-50 KNOTS). LATEST MESOANALYSIS SUGGESTS A HIGHER BUOYANCY AXIS  
EXISTS FROM SOUTHEAST WI INTO WEST-CENTRAL/NORTHERN LOWER MI, SO THE  
SEVERE THREAT MAY BE MAXIMIZED ACROSS THIS CORRIDOR IN THE COMING  
HOURS. HOWEVER, SEVERE THUNDERSTORM COVERAGE SHOULD REMAIN LIMITED  
GIVEN THE OVERALL MARGINAL KINEMATIC ENVIRONMENT.  
 
..MOORE/SMITH.. 04/23/2024  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...DTX...APX...IWX...GRR...LOT...MKX...DVN...  
 
LAT...LON 42488950 43578801 44268639 44628527 44778397 44328368  
43908355 43568358 43318386 42828463 42128642 41808735  
41608809 41558865 41568906 41568926 41978954 42178960  
42488950  
 
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