079  
ACUS11 KWNS 010215  
SWOMCD  
SPC MCD 010215  
IAZ000-NEZ000-SDZ000-010415-  
 
MESOSCALE DISCUSSION 0927  
NWS STORM PREDICTION CENTER NORMAN OK  
0915 PM CDT SUN MAY 31 2026  
 
AREAS AFFECTED...FAR SOUTHEAST SOUTH DAKOTA INTO ADJACENT PORTIONS  
OF NEBRASKA AND IOWA  
 
CONCERNING...SEVERE THUNDERSTORM WATCH 257...  
 
VALID 010215Z - 010415Z  
 
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 257  
CONTINUES.  
 
SUMMARY...A LOCALIZED CORRIDOR OF HIGHER TORNADO POTENTIAL MAY  
PERSIST FOR THE NEXT COUPLE OF HOURS ACROSS FAR SOUTHEAST SOUTH  
DAKOTA INTO ADJACENT PORTIONS OF IOWA AND NEBRASKA.  
 
DISCUSSION...ADDITIONAL TORNADIC SUPERCELLS HAVE EMERGED IMMEDIATELY  
WEST OF THE SIOUX FALLS, SD AND THE I-29 CORRIDOR BASED ON RADAR  
IMAGERY FROM KFSD. NEAR-STORM 0-1 KM SRH SAMPLED BY THE LOCAL VWP  
HAS RECENTLY INCREASED TO AROUND 200 M2/S2 IMMEDIATELY AHEAD OF THE  
APPROACHING STORMS. CONSEQUENTLY, THE NEAR-STORM ENVIRONMENT IS MORE  
FAVORABLE FOR TORNADOES THAN PREVIOUSLY ANTICIPATED, THOUGH STORM  
INTERACTIONS APPEAR TO BE MODULATING THE DURATION OF THE TORNADO  
THREAT TO SOME DEGREE. ADDITIONAL SUPERCELL DEVELOPMENT IS NOTED ON  
THE SOUTHERN FLANK OF THE EMERGING CLUSTER, AND IS ALREADY SHOWING  
SIGNS OF AN ORGANIZING LOW-LEVEL MESOCYCLONE. IT APPEARS LIKELY THAT  
SOME TORNADO THREAT WILL LIKELY CONTINUE FOR THE NEXT 1-2 HOURS -  
MOST LIKELY ON THE SOUTHERN FLANK OF THE CLUSTER AS IT MIGRATES  
EAST/SOUTHEAST INTO FAR NORTHEAST NE/NORTHWEST IA. BASED ON THE  
NEAR-STORM ENVIRONMENT AND OBSERVED VELOCITY SIGNATURES, A STRONG  
TORNADO APPEARS POSSIBLE.  
 
..MOORE.. 06/01/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...FSD...OAX...  
 
LAT...LON 42589728 43109709 43329697 43359662 43289611 43139602  
42919595 42689607 42519629 42459661 42489704 42589728  
 
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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