MESOSCALE DISCUSSION 0473
   NWS STORM PREDICTION CENTER NORMAN OK
   0655 PM CDT MON APR 13 2009
   
   AREAS AFFECTED...PARTS OF SERN LA INTO CNTRL/SRN MS
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 152...
   
   VALID 132355Z - 140130Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 152
   CONTINUES.
   
   CONTINUE REMAINING VALID PORTIONS OF WW UNTIL 01Z EXPIRATION.  THE
   NEED FOR AN ADDITIONAL WW IS NOT CURRENTLY ANTICIPATED FARTHER TO
   THE EAST...BUT TRENDS WILL BE MONITORED.
   
   INSTABILITY WITHIN A NARROW PRE-FRONTAL THERMAL RIDGE HAS PROVIDED
   SUPPORT FOR SCATTERED VIGOROUS STORM DEVELOPMENT DURING THE PAST FEW
   HOURS...DRIVEN BY LOW-LEVEL WARM ADVECTION AND THE INCREASING
   INFLUENCE OF A SHORT WAVE TROUGH PIVOTING TOWARD THE LOWER
   MISSISSIPPI VALLEY.  AS THE BOUNDARY LAYER BEGINS TO COOL/STABILIZE
   WITH THE LOSS OF DAYTIME HEATING BY THE 01-02Z TIME FRAME...AND
   LATER BY THE PASSAGE OF THE COLD FRONT...STORM INTENSITY IS EXPECTED
   TO GENERALLY DIMINISH.  HOWEVER...IT IS STILL POSSIBLE THAT STORM
   COVERAGE COULD INCREASE EAST OF MERIDIAN INTO THE BIRMINGHAM/SELMA
   AND MONTGOMERY AREAS OF CENTRAL ALABAMA...IN RESPONSE TO STRONGER
   LARGE-SCALE FORCING...THROUGH THE 02-04Z TIME FRAME.
   
   ..KERR.. 04/13/2009
   
   
   ATTN...WFO...BMX...MOB...JAN...LIX...
   
   LAT...LON   32048941 33248814 33698758 33868668 32888648 31978701
               30538980 30849074 32048941