275  
ACUS11 KWNS 171933  
SWOMCD  
SPC MCD 171932  
MIZ000-172200-  
 
MESOSCALE DISCUSSION 0751  
NWS STORM PREDICTION CENTER NORMAN OK  
0232 PM CDT SUN MAY 17 2026  
 
AREAS AFFECTED...PORTIONS OF CENTRAL LOWER MICHIGAN  
 
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE  
 
VALID 171932Z - 172200Z  
 
PROBABILITY OF WATCH ISSUANCE...40 PERCENT  
 
SUMMARY...THUNDERSTORMS MAY POSE A RISK FOR LARGE HAIL AND DAMAGING  
WIND GUSTS, WITH SOME POTENTIAL FOR A TORNADO OR TWO. WATCH ISSUANCE  
IS POSSIBLE.  
 
DISCUSSION...LATEST GOES WATER VAPOR IMAGERY REVEALS AN MCV OVER  
SOUTH-CENTRAL WISCONSIN, IN CLOSE PROXIMITY TO PERSISTENT ELEVATED  
CONVECTION THAT HAS BEEN ONGOING THROUGH THE MORNING AND INTO THE  
AFTERNOON HOURS. DOWNSTREAM OF THESE FEATURES, LATEST SURFACE  
ANALYSIS INDICATES A QUASI-STATIONARY SURFACE BOUNDARY/WARM FRONT  
EXTENDING ROUGHLY WEST-EAST ACROSS CENTRAL LOWER MICHIGAN WITH  
RECENT CONVECTIVE DEVELOPMENT NOTED NORTH OF GRAND RAPIDS. SOUTH OF  
THIS BOUNDARY, TEMPERATURES IN THE MID-80S AND DEWPOINTS IN THE LOW  
60S F ARE CONTRIBUTING 500 TO LOCALLY 1500 J/KG MLCAPE. 35-45 KTS OF  
EFFECTIVE BULK SHEAR (PER LATEST MESOANALYSIS) IS SUFFICIENT TO  
SUPPORT MULTICELLS/SUPERCELLS WITH ANY CONVECTION THAT DEVELOPS  
ALONG/SOUTH OF THIS BOUNDARY. THIS WILL PROMOTE THE POTENTIAL FOR  
LARGE HAIL AND DAMAGING WIND GUSTS WITH ANY SUSTAINED CONVECTION  
THIS AFTERNOON.  
 
WITH TIME, A STRENGTHENING SOUTHERLY LOW-LEVEL JET IS FORECAST TO  
YIELD AN INCREASE IN LOW-LEVEL HODOGRAPH CURVATURE INTO THIS  
EVENING, WHICH WOULD FAVOR AT LEAST SOME INCREASE IN THE THREAT FOR  
A TORNADO OR TWO, PARTICULARLY WITH ANY SUPERCELL/CONVECTION THAT  
CAN FAVORABLY INTERACT WITH THE WARM FRONT. UNCERTAINTY REMAINS  
REGARDING CONVECTIVE COVERAGE AND PERSISTENCE WITHIN THE WARM  
SECTOR, HOWEVER. TRENDS WILL CONTINUE TO BE MONITORED, AND WATCH  
ISSUANCE MAY EVENTUALLY BE NEEDED.  
 
..CHALMERS/MOSIER.. 05/17/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...DTX...APX...GRR...  
 
LAT...LON 42718592 42888628 43378655 43828661 44218648 44508618  
44588460 44578373 44478329 44208285 43898253 43528246  
43198259 42958316 42808366 42728508 42718592  
 
MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH  
MOST PROBABLE PEAK WIND GUST...55-70 MPH  
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN  
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