MESOSCALE DISCUSSION 1830
   NWS STORM PREDICTION CENTER NORMAN OK
   0756 PM CDT SAT AUG 08 2009
   
   AREAS AFFECTED...PARTS OF WRN SD
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 090056Z - 090230Z
   
   THE THREAT FOR ISOLATED SEVERE STORMS CAPABLE OF LOCALLY STRONG WIND
   GUSTS AND HAIL IS EXPECTED TO SPREAD FROM THE WY/SD EWD ACROSS PARTS
   OF WRN SD THIS EVENING.  A WW IS NOT CURRENTLY ANTICIPATED.
   
   TSTMS WHICH INITIATED THIS AFTERNOON OVER PARTS OF SERN MT AND NERN
   WY APPEAR TO BE MERGING INTO A CLUSTER FROM CROOK COUNTY WY INTO
   BUTTE COUNTY SD AS OF 0050Z.  INDIVIDUAL STORM MOTIONS WERE
   270/25-30 KT.  WHILE MIDLEVEL LAPSE RATES ARE NOT PARTICULARLY
   STEEP...00Z RAP SOUNDING INDICATED THE PRESENCE OF A RELATIVELY
   MOIST BOUNDARY LAYER WITH MLCAPE OF AROUND 500 J/KG.  INSTABILITY
   SHOULD DECREASE WITH TIME THIS EVENING WITH THE ONSET OF NOCTURNAL
   COOLING.  HOWEVER...THE PRESENCE OF A STRENGTHENING SYSTEM COLD POOL
   AND AROUND 50 KT OF DEEP-LAYER SHEAR MAY SERVE TO MAINTAIN STORMS
   WITH A CONTINUED THREAT OF LOCALLY STRONG WIND GUSTS AND HAIL.
   
   ..MEAD.. 08/09/2009
   
   
   ATTN...WFO...UNR...
   
   LAT...LON   43500322 43690381 44770407 45270383 45340314 44830213
               44210199 43650236 43430302 43500322