MESOSCALE DISCUSSION 0789
   NWS STORM PREDICTION CENTER NORMAN OK
   0348 PM CDT SUN MAY 10 2009
   
   AREAS AFFECTED...CNTRL MS...NRN LA AND NERN TX
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 286...
   
   VALID 102048Z - 102215Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 286
   CONTINUES.
   
   THE THREAT FOR PRIMARILY ISOLATED DOWNBURSTS AND LARGE HAIL WILL
   CONTINUE NEXT SEVERAL HOURS OVER NRN AR SPREADING EWD THROUGH CNTRL
   MS...THROUGH A BRIEF TORNADO OR TWO CANNOT BE RULED OUT. STORMS OVER
   NE TX ARE BEING MONITORED FOR INTENSIFICATION...AND WW 286 MIGHT
   NEED TO BE EXTENDED A FEW COUNTIES WWD. 
   
   THIS AFTERNOON A QUASISTATIONARY FRONT EXTENDS FROM SRN MS WNWWD
   THROUGH N CNTRL AR INTO NE TX. THE WRN PORTIONS OF THE FRONT HAS
   SHOWN A TENDENCY TO DEVELOP FARTHER NWD. A CONVECTIVELY ENHANCED
   BOUNDARY EXTENDS FROM CNTRL MS WWD TO JUST SOUTH OF THE LA/AR BORDER
   INTO NERN TX. THIS BOUNDARY IS MOVING SWD. PRE-FRONTAL WARM SECTOR
   REMAINS MODERATELY UNSTABLE WITH 2500 J/KG MLCAPE AND 7C/KM MID
   LEVEL LAPSE RATS FROM NERN TX THROUGH LA INTO S CNTRL MS. LOW LEVEL
   HODOGRAPHS REMAIN SMALL DUE TO ABSENCE OF A LOW LEVEL JET.
   HOWEVER...SOME STORMS DEVELOPING ALONG AND NORTH OF THE FRONTAL
   BOUNDARY OVER NRN LA HAVE EXHIBITED SUPERCELL CHARACTERISTICS WHERE
   LOW LEVEL WINDS ARE BACKED TO ELY BENEATH 30 KT WLY 700-500 MB
   FLOW...RESULTING IN 35-40 KT BULK SHEAR. POTENTIAL FOR AN ISOLATED
   BRIEF TORNADO OR IS POSSIBLE WITH STORMS INTERACTING WITH THE
   BOUNDARY.
   
   STORMS DEVELOPING FARTHER WEST ACROSS NERN TX HAVE BEEN SLOW TO
   INTENSIFY...POSSIBLY DUE TO MORE PRONOUNCED INVERSION IN THIS
   REGION...BUT ACTIVITY WILL HAVE POTENTIAL TO INCREASE AS IT MOVES 
   EWD. THE SWD MOVING OUTFLOW BOUNDARY MAY EVENTUALLY MERGE WITH THE
   FRONT DURING THE NEXT HOUR OR TWO...AND THIS MAY CONTRIBUTE TO AN
   INCREASE IN STORM INTENSITY AND COVERAGE FROM NERN TX INTO NRN LA.
   
   ..DIAL.. 05/10/2009
   
   
   ATTN...WFO...JAN...LZK...SHV...
   
   LAT...LON   33178870 31888900 31579326 32039455 32759409 33219328
               33209233 33178870