MESOSCALE DISCUSSION 0491
   NWS STORM PREDICTION CENTER NORMAN OK
   0931 PM CDT THU MAR 27 2008
   
   AREAS AFFECTED...ERN OK...SRN MO THROUGH SRN AND S CNTRL IL
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 138...139...
   
   VALID 280231Z - 280400Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   138...139...CONTINUES.
   
   THREAT FOR LARGE HAIL WILL PERSIST NEXT COUPLE HOURS MAINLY FROM ERN
   OK INTO SRN MO. GREATEST SHORT TERM SEVERE THREAT REMAINS WITH
   CLUSTER OF SURFACE BASED STORMS OVER SERN MO. OVERALL TREND WILL BE
   FOR THE SURFACE BASED STORMS TO BEGIN A GRADUAL DECREASE WITH
   PRIMARY CONVECTIVE ZONE BECOMING POST FRONTAL.
   
   COLD FRONT EXTENDS FROM SRN IND THROUGH SRN MO...NW AR...ERN AND SRN
   OK. MODERATE INSTABILITY EXISTS IN WARM SECTOR SOUTH OF FRONT.
   HOWEVER...INCREASING CONVECTIVE INHIBITION RESULTING FROM NOCTURNAL
   COOLING AND PRESENCE OF WARMER EML WITH SWD EXTENT INTO OK AND AR
   HAVE RESULTED IN SURFACE BASED STORMS UNDERGOING A GRADUAL WEAKENING
   TREND. GREATEST SEVERE THREAT REMAINS WITH SUPERCELLS IN SERN MO. AN
   ISOLATED TORNADO OR TWO AND LARGE HAIL REMAIN POSSIBLE WITH THIS
   ACTIVITY. HOWEVER...AS THE STORMS CONTINUE SEWD TOWARD A MORE STABLE
   BOUNDARY LAYER...THEY WILL LIKELY UNDERGO A GRADUAL DECREASE IN
   INTENSITY. OTHER STORMS HAVE DEVELOPED WITHIN ZONE OF DEEPER POST
   FRONTAL ASCENT AND WEAKER CAP ACROSS SWRN MO. THIS ACTIVITY IS
   ELEVATED. HOWEVER...FORECAST RUC SOUNDINGS SHOW MODEST INSTABILITY
   WITH STEEP MID LEVEL LAPSE RATES AND EFFECTIVE SHEAR SUFFICIENT FOR
   ROTATION WHICH WILL ENHANCE THE THREAT FOR HAIL NEXT COUPLE HOURS.
   
   ..DIAL.. 03/28/2008
   
   
   ATTN...WFO...PAH...ILX...LSX...LZK...SGF...TSA...
   
   35989376 34769460 34799606 36139505 37339481 38109273
   38969063 39518929 39128820 36829113