MESOSCALE DISCUSSION 2211
   NWS STORM PREDICTION CENTER NORMAN OK
   1210 PM CDT WED SEP 28 2011
   
   AREAS AFFECTED...SERN TX/SRN LA/SRN MS
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 281710Z - 281915Z
   
   SEVERE THREAT IS EXPECTED TO SLOWLY INCREASE THIS AFTERNOON AS
   STORMS DEVELOP/INTENSIFY WITH TIME.  EVENTUAL WW ISSUANCE IS
   POSSIBLE.
   
   LATEST VISIBLE SATELLITE AND RADAR LOOPS SHOW CONVECTION SLOWLY
   DEVELOPING ACROSS THE DISCUSSION AREA...BOTH INVOF A SEA BREEZE
   BOUNDARY NEAR THE SERN TX/SRN LA COAST AND ALSO FARTHER N INTO SRN
   MS NEAR THE SYNOPTIC-SCALE FRONT.  THE CONVECTION IS INITIATING
   WITHIN A THERMODYNAMIC ENVIRONMENT FEATURING VERY STEEP LAPSE RATES
   THROUGH A DEEP LAYER...AND A VERY MOIST BOUNDARY LAYER.  THIS
   COMBINED WITH DIURNAL HEATING IS YIELDING MIXED-LAYER CAPE VALUES
   NOW AS HIGH AS 3500 J/KG FROM SERN TX EWD ACROSS SRN LA. 
   
   AS HEATING/DESTABILIZATION CONTINUES...AND AS A COMPACT UPPER
   LOW/VORT MAX SHIFTS SEWD OUT OF OK INTO THE ARKLATEX
   REGION...LARGE-SCALE ASCENT SHOULD INCREASE ACROSS THE DISCUSSION
   AREA...SUPPORTING AN INCREASE IN BOTH STORM COVERAGE AND INTENSITY. 
   WHILE PROFILER/VWP DATA AND MORNING RAOBS REVEAL MODEST FLOW ALOFT
   -- AND THUS SHEAR VALUES GENERALLY UNSUPPORTIVE OF
   SUPERCELLS...DEGREE OF INSTABILITY APPEARS SUFFICIENT TO OVERCOME
   THIS LIMITATION AND YIELD AN INCREASING POTENTIAL FOR LARGE HAIL AND
   LOCALLY DAMAGING WINDS THROUGH THE AFTERNOON.  WHILE WW IS NOT
   IMMINENT...INCREASING POTENTIAL MAY EVENTUALLY WARRANT WATCH
   ISSUANCE.
   
   ..GOSS.. 09/28/2011
   
   
   ATTN...WFO...MOB...JAN...LIX...LCH...SHV...HGX...
   
   LAT...LON   29149485 29219573 29819596 30829504 31449374 31599184
               31749049 31288888 30638849 29618947 29399067 29639252
               29749414 29149485