MESOSCALE DISCUSSION 0502
   NWS STORM PREDICTION CENTER NORMAN OK
   1000 AM CDT THU APR 21 2011
   
   AREAS AFFECTED...NERN/ERN LA...CNTRL/SRN MS
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 211500Z - 211630Z
   
   A FEW DAMAGING WIND GUSTS AND LARGE HAIL CAN BE EXPECTED TO SPREAD
   SLOWLY DOWNSTREAM ACROSS THE LOWER MS VALLEY THROUGH THE AFTERNOON. 
   A SEVERE THUNDERSTORM WATCH IS POSSIBLE...ROUGHLY 30 PERCENT CHANCE.
   
   
   MCS WAS THRIVING ACROSS THE LOWER MS VALLEY AT MID-MORNING...BOTH
   REGENERATING ALONG/N OF AN OUTFLOW BOUNDARY SITUATED ALONG THE AR/LA
   BORDER AND SLOWLY PROPAGATING WITH THE MEAN WIND FLOW ALONG IT/S
   FORWARD FLANK.  ALTHOUGH OVERALL LARGE-SCALE FORCING AND SELY INFLOW
   INTO THE SYSTEM WILL REMAIN WEAK...MODEST PRECIPITATION LOADING AND
   AT LEAST 30-35 KTS OF DEEP WLY UNIDIRECTIONAL FLOW MAY YIELD BOWING
   TYPE STRUCTURES GIVING LOCAL DAMAGING WIND GUSTS.  THIS WILL
   ESPECIALLY BE THE CASE AS THE DOWNSTREAM LOW-LEVEL LAPSE RATES
   STEEPEN AND COMPENSATE FOR ONLY MODEST WIND FLOW/SYSTEM SPEED. 
   OTHERWISE...LARGE HAIL WILL ALSO BE POSSIBLE AS INCIPIENT UPDRAFTS
   TAKE ADVANTAGE OF AROUND 7 DEG C PER KM H7-H5 LAPSE RATES.
   
   ..RACY.. 04/21/2011
   
   
   ATTN...WFO...MOB...JAN...LIX...SHV...
   
   LAT...LON   32889080 32358858 31458884 31078948 30969045 31169141
               31689225 32539271 32439146 32669112 32889080