MESOSCALE DISCUSSION 1612
   NWS STORM PREDICTION CENTER NORMAN OK
   0555 PM CDT FRI JUL 04 2003
   
   AREAS AFFECTED...SRN SD AND EXTREME NCNTRL/NERN NEB
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL...SEVERE THUNDERSTORM
   WATCH 637...
   
   VALID 042255Z - 050030Z
   
   SEVERE TSTMS CLUSTER IS MOVING 295/35-40 KTS WITH HISTORY OF SEVERE
   GUSTS IN THE RAPID CITY AREA.  DOWNSTREAM AIR MASS REMAINS UNSTABLE
   AND WAS ABLE TO RECOVER FROM LAST NIGHTS MCS...WITH 100 MB MEAN
   MIXED CAPE AXIS OF AROUND 2000 J/KG INTO THE FSD AREA. PRIND THAT
   TSTMS WILL MOVE/DEVELOP EWD INTO ERN SD AND PERHAPS NCNTRL/NERN NEB
   WITH TIME THIS EVENING...WITHIN INSTABILITY AXIS.  THE REGION
   RESIDES WITHIN THE SRN EDGE OF STRONGER FLOW ASSOCIATED WITH POTENT
   MIDLEVEL WAVE PASSING THROUGH NRN SD.  MAGNITUDE OF FLOW AND
   INSTABILITY IN PLACE MAY KEEP A DAMAGING WIND THREAT
   DOWNSTREAM...REACHING THE ERN EDGE OF WS 637 AROUND 0200 UTC.  IF
   TSTMS ARE MAINTAINED...ANOTHER WW MAY BE REQUIRED ACROSS ERN SD AND
   PERHAPS PARTS OF NRN NEB.
   
   ..RACY.. 07/04/2003
   
   
   ATTN...WFO...ABR...UNR...FSD...OAX...GID...LBF...
   
   43370398 45200396 45259986 43049982 43030396 
   
   42619691 41739839 41960048 42910153 43019975 45099976
   45289859 45029718 44069671