973  
ACUS11 KWNS 280010  
SWOMCD  
SPC MCD 280010  
NEZ000-SDZ000-COZ000-280145-  
 
MESOSCALE DISCUSSION 1358  
NWS STORM PREDICTION CENTER NORMAN OK  
0710 PM CDT SAT JUN 27 2026  
 
AREAS AFFECTED...PORTIONS OF SOUTHWESTERN SOUTH DAKOTA INTO THE  
NEBRASKA PANHANDLE  
 
CONCERNING...TORNADO AND SEVERE THUNDERSTORM WATCHES 406...407...  
 
VALID 280010Z - 280145Z  
 
THE SEVERE WEATHER THREAT FOR TORNADO AND SEVERE THUNDERSTORM  
WATCHES 406, 407 CONTINUES.  
 
SUMMARY...ISOLATED TO WIDELY SCATTERED CONVECTION CONTINUES TO POSE  
A RISK FOR PRIMARILY LARGE HAIL AND DAMAGING WIND GUSTS.  
 
DISCUSSION...ISOLATED TO WIDELY SCATTERED SUPERCELLS HAVE DEVELOPED  
ACROSS FAR SOUTHWESTERN SOUTH DAKOTA AND NORTHWESTERN NEBRASKA AS OF  
2350 UTC TO THE WEST OF A DIFFUSE DRYLINE. IN THE NEAR-TERM, THE  
PRIMARY RISK ASSOCIATED WITH THIS CONVECTION WILL BE LARGE TO VERY  
LARGE HAIL (PERHAPS TO 2.5+ INCHES IN DIAMETER) GIVEN STRONG  
EFFECTIVE SHEAR, ELONGATED HODOGRAPHS, AND AMPLE BUOYANCY WITHIN THE  
HAIL GROWTH ZONE (AS SUPPORTED BY SHIP VALUES RANGING FORM 1-3+ PER  
LATEST OBJECTIVE ANALYSIS). RECENT HIGH-RES GUIDANCE AND REGIONAL  
RADAR IMAGERY SUGGEST THAT RAPID UPSCALE GROWTH MAY OCCUR WITH THE  
ONGOING CONVECTION ACROSS SOUTHWESTERN SOUTH DAKOTA, WHICH WOULD  
FAVOR A TRANSITION TOWARDS DAMAGING/SEVERE WIND GUSTS AS THE PRIMARY  
RISK. FARTHER SOUTH, ONGOING CONVECTION IS LIKELY TO REMAIN MORE  
ISOLATED WITHIN THE NEBRASKA PANHANDLE, WITH LARGE TO VERY LARGE  
HAIL AND DAMAGING WIND GUSTS BEING POSSIBLE WITH SUPERCELLS.  
ADDITIONAL DEVELOPMENT FARTHER SOUTH INTO SOUTHWESTERN NEBRASKA  
REMAINS UNCERTAIN AT THIS TIME.  
 
SOME INCREASE IN TORNADO POTENTIAL MAY OCCUR WITH TIME AND AS  
CONVECTION PROGRESSES EASTWARD GIVEN GREATER MOISTURE TO THE EAST OF  
THE DIFFUSE DRYLINE AND A STRENGTHENING NOCTURNAL LOW-LEVEL JET THAT  
WILL YIELD INCREASINGLY CLOCKWISE-CURVED LOW-LEVEL HODOGRAPHS. A  
MORE LINEAR STORM MODE AND GREATER CONVECTIVE INHIBITION/CAPPING TO  
THE EAST OF THE DRYLINE LEND UNCERTAINTY TO THE MAGNITUDE OF THE  
TORNADO RISK, HOWEVER. THE GREATEST RISK FOR A TORNADO IS LIKELY TO  
OCCUR WITH ANY DISCRETE SUPERCELL THAT CAN PERSIST FARTHER EAST INTO  
THIS EVENING.  
 
..CHALMERS.. 06/28/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...LBF...UNR...BOU...CYS...  
 
LAT...LON 42850344 43350333 44010309 44450267 44570214 44510176  
44290145 43770139 42630136 41790140 41220147 40990164  
40850201 40800247 41030294 41680332 42170338 42850344  
 
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH  
MOST PROBABLE PEAK WIND GUST...65-80 MPH  
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN  
 
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