803  
ACUS11 KWNS 171950  
SWOMCD  
SPC MCD 171949  
WIZ000-IAZ000-MNZ000-172145-  
 
MESOSCALE DISCUSSION 0476  
NWS STORM PREDICTION CENTER NORMAN OK  
0249 PM CDT FRI APR 17 2026  
 
AREAS AFFECTED...CENTRAL/EASTERN IOWA INTO SOUTHEASTERN MINNESOTA  
 
CONCERNING...TORNADO WATCH 129...  
 
VALID 171949Z - 172145Z  
 
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 129 CONTINUES.  
 
SUMMARY...THREAT FOR LARGE TO VERY LARGE HAIL, WIND, AND TORNADOES  
CONTINUES WITHIN WW129.  
 
DISCUSSION...THUNDERSTORM ACTIVITY HAS INCREASED ALONG THE COLD  
FRONT IN CENTRAL IOWA INTO SOUTHEASTERN MINNESOTA. MODE IS RATHER  
MIXED, WITH CLUSTERS AND MORE SEMI-DISCRETE SUPERCELLS ALONG AND  
AHEAD OF THE FRONT. REPORTS OF LARGE HAIL 1-1.75 INCHES IN DIAMETER  
AND A TORNADO WERE REPORTED NEAR OLMSTEAD, MN. THE THREAT FOR LARGE  
HAIL, TORNADOES, AND DAMAGING WIND WILL CONTINUE OVER THE NEXT  
SEVERAL HOURS. DAYTIME HEATING AND WARM AIR ADVECTION HAS YIELDED  
MLCAPE AROUND 2000-3000 J/KG. THE 18Z RAOB FROM DVN SHOWS THIS WELL,  
WITH ANALYZED 2100 J/KG MLCAPE, STEEP LOW TO MID-LEVEL LAPSE RATES  
AND AN ENLARGED CLOCK-WISE LOW-LEVEL HODOGRAPH.  
 
AS THE FRONT MOVES EASTWARD AND MODE SHIFTS TO BECOME MORE LINEAR,  
THE MAIN THREATS WILL SHIFT TO DAMAGING WIND AND CONTINUED POTENTIAL  
FOR LINE EMBEDDED TORNADOES. WITH ANY SUPERCELLS THAT CAN MAINTAIN  
AHEAD OF THE LINE (PARTICULARLY FROM EASTERN IOWA INTO SOUTHERN  
WISCONSIN), LARGE HAIL, AND STRONG TORNADO POTENTIAL WILL CONTINUE.  
 
..THORNTON.. 04/17/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...DVN...ARX...MPX...DMX...  
 
LAT...LON 44689181 44719166 44089098 43199071 42469086 41279180  
40809269 40839376 41469364 43379278 44239250 44559207  
44689181  
 
MOST PROBABLE PEAK TORNADO INTENSITY...120-150 MPH  
MOST PROBABLE PEAK WIND GUST...65-80 MPH  
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN  
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