282  
ACUS11 KWNS 300030  
SWOMCD  
SPC MCD 300030  
IAZ000-MNZ000-NEZ000-SDZ000-300200-  
 
MESOSCALE DISCUSSION 1839  
NWS STORM PREDICTION CENTER NORMAN OK  
0730 PM CDT TUE JUL 29 2025  
 
AREAS AFFECTED...PORTIONS OF SOUTHEASTERN SOUTH DAKOTA INTO  
NORTHEAST NEBRASKA AND NORTHWESTERN IOWA  
 
CONCERNING...SEVERE THUNDERSTORM WATCH 557...  
 
VALID 300030Z - 300200Z  
 
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 557  
CONTINUES.  
 
SUMMARY...THE SEVERE GUST THREAT SHOULD PERSIST WITH THE ONGOING MCS  
FOR AT LEAST A COUPLE MORE HOURS. IT IS UNCLEAR HOW FAR SOUTHEAST  
THE MCS WILL PROGRESS, SO CONDITIONS WILL CONTINUE TO BE MONITORED  
FOR THE NEED OF ANY DOWNSTREAM SEVERE THUNDERSTORM WATCHES.  
 
DISCUSSION...A COLD-POOL-DRIVEN MCS, WITH A HISTORY OF SEVERAL  
REPORTED SEVERE WIND GUSTS, CONTINUES TO GRADUALLY PROPAGATE TO THE  
EAST-SOUTHEAST OVER SOUTHEASTERN SD. EXTREME BUOYANCY (I.E.  
3000-5000 J/KG MLCAPE) PRECEDES THE MCS, BUT WITH MARGINAL  
DEEP-LAYER SHEAR AND WEAK LOW-LEVEL SHEAR. AS SUCH, THE MCS  
CONTINUES TO PROPAGATE FORWARD AT ONLY 30 KTS, WITH MRMS MOSAIC  
RADAR DATA SHOWING SLIGHT WEAKENING TRENDS (I.E. OVERALL WEAKER  
ECHOES EXCEEDING 50 KFT). IT IS UNCLEAR HOW FAR SOUTHEAST THE MCS  
WILL PROPAGATE, ESPECIALLY SINCE A RESIDUAL NORTHWEST-TO-SOUTHEAST  
ORIENTED FRONTAL BOUNDARY CONTINUES TO PUSH SOUTHWESTWARD ACROSS THE  
MCS PATH WITH COOLER AND POTENTIALLY MORE STABLE AIR. NONETHELESS,  
GIVEN EXISTENT STRONG TO EXTREME BUOYANCY, MCS BEHAVIOR WILL  
CONTINUE TO BE MONITORED FOR THE POSSIBLE NEED OF A DOWNSTREAM  
SEVERE THUNDERSTORM WATCH ISSUANCE.  
 
..SQUITIERI/MOSIER.. 07/30/2025  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...DMX...FSD...OAX...LBF...  
 
LAT...LON 43859779 43699654 43269549 42629510 42199521 41999570  
42029652 42189764 42389843 42499868 43859779  
 
MOST PROBABLE PEAK WIND GUST...65-80 MPH  
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