MESOSCALE DISCUSSION 0312
   NWS STORM PREDICTION CENTER NORMAN OK
   0856 PM CDT TUE MAR 29 2011
   
   AREAS AFFECTED...SERN LA/SRN MS/SWRN AL
   
   CONCERNING...TORNADO WATCH 72...
   
   VALID 300156Z - 300300Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 72 CONTINUES.
   
   MOIST ISENTROPIC ASCENT...COMBINED WITH UPPER-LEVEL JET
   SUPPORT...WILL CONTINUE TO ALLOW CONVECTION TO PERSIST/DEVELOP
   ACROSS ERN PORTIONS OF TORNADO WATCH 72 DURING THE NEXT SEVERAL
   HOURS...WITH SUPERCELLS POSSIBLE GIVEN EFFECTIVE BULK SHEAR
   MAGNITUDES OF 40 TO 50 KT PER RUC ANALYSIS. SFC ANALYSIS REVEALS
   MULTIPLE BOUNDARIES ACROSS THE AREA TO FOCUS CONVECTION THROUGH THE
   REMAINDER OF THE EVENING HOURS:
   1. A WARM FRONT EXTENDS FROM A SFC LOW OVER S-CNTRL LOUISIANA INTO
   FAR SERN LA AND THE ADJACENT COASTAL WATERS...WITH DEWPOINTS IN THE
   UPPER 60S AND LOWER 70S AND MLCAPE VALUES AOA 2000 J/KG SOUTH OF
   THIS BOUNDARY. A CYCLIC SUPERCELL RIDING SEWD ALONG THIS BOUNDARY
   THAT MOVED SOUTH OF YSCLOSKEY IS EMERGING INTO THE COASTAL
   WATERS...WITH ADDITIONAL SUPERCELLS POTENTIALLY DEVELOPING UPSTREAM
   ALONG THE WARM FRONT.
   2. A SECONDARY WARM FRONT EXTENDS EAST OF THE LOW ACROSS SRN
   MS...WHICH COULD ALSO ENHANCE CONVECTION THAT FORMS NORTH OF THE SRN
   WARM FRONT.
   3. NORTH OF THE SECONDARY WARM FRONT...SLIGHTLY ELEVATED INSTABILITY
   EXTENDS TOWARD THE NRN PORTION OF THE TORNADO WATCH...WHICH COULD
   SUPPORT A LARGE HAIL THREAT.
   
   WITH 0-1-KM SRH VALUES OF 100 TO 200 M2 PER S2 ACROSS THE REGION
   /105 M2 PER S2 BASED ON VWP AT LIX/...A MARGINAL TORNADO THREAT WILL
   CONTINUE...WITH THE GREATEST THREAT NEAR EITHER OF THE WARM FRONTS.
   THUS...ANOTHER TORNADO WATCH MAY BECOME NECESSARY PRIOR TO THE 03Z
   EXPIRATION OF WW 72.
   
   ..COHEN.. 03/30/2011
   
   
   ATTN...WFO...MOB...JAN...LIX...LCH...
   
   LAT...LON   31598934 31278852 30008831 29148877 28938976 29089086
               29739154 31019156 31449067 31598934