MESOSCALE DISCUSSION 0611
   NWS STORM PREDICTION CENTER NORMAN OK
   1133 PM CDT TUE APR 26 2011
   
   AREAS AFFECTED...PORTIONS SE TX...WRN/NRN LA...SERN
   AR...WRN/CENTRAL/NRN MS...EXTREME NWRN AL.
   
   CONCERNING...TORNADO WATCH 222...223...
   
   VALID 270433Z - 270630Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 222...223...CONTINUES.
   
   CONTINUE WWS ALONG/AHEAD OF CONVECTIVE BEND DELINEATED BELOW. 
   ADDITIONAL AREAS OF SERN/CENTRAL LA MAY NEED TO BE ADDED TO ONE OF
   THESE WWS AS CONVECTIVE TRENDS WARRANT.
   
   BKN BELT OF SVR TSTMS IN CLUSTERS WAS EVIDENT AT 04Z FROM WRN TN
   SWWD ACROSS NRN LA TO E TX.  CLUSTERS OVER SERN AR/NRN LA AND OVER E
   TX REMAIN SEPARATED BY WEAKER CONVECTION ATTM BUT MAY CONGEAL INTO
   MORE SOLIDLY DEFINED/QUASI-LINEAR COMPLEX WITH EMBEDDED SUPERCELLS. 
   RICH BOUNDARY-LAYER THETAE WILL HELP FAVORABLE BUOYANCY TO PERSIST
   WITH MLCAPE GENERALLY IN 1500-2500 J/KG.  EXTREME ENVIRONMENTAL
   SHEAR PROFILES HAVE BEGUN TO SPREAD OVER THIS REGION AS MID-UPPER
   TROUGH CROSSES SRN PLAINS AND TIGHTENING HEIGHT GRADIENTS OVERSPREAD
   WARM SECTOR.  LA/MS REGIME INCLUDES 70-90 KT EFFECTIVE SHEAR
   MAGNITUDES AND LLJ-AIDED 0-1 KM SRH OF 400-600 J/KG...WHICH ARE
   QUITE EXTRAORDINARY VALUES FOR WARM SECTOR CONTAINING SFC DEW POINTS
   IN UPPER 60S TO LOW 70S F.  DEEP-LAYER SHEAR WILL REMAIN NEARLY AS
   STG WITH SLIGHTLY LOWER SRH WWD ACROSS SE TX...BUT STILL FAVORABLE
   FOR TORNADIC SUPERCELLS.  MAIN LIMITING FACTOR OVER TX WILL BE
   STRENGTHENING MLCINH...BOTH WITH TIME AND WITH WWD EXTENT. 
   CONVECTIVE MODE WILL REMAIN RATHER MESSY ACROSS ENTIRE WW...HOWEVER
   EVEN EMBEDDED/HEAVY-PRECIP SUPERCELLS MOVING EWD FROM NRN LA/SERN AR
   INTO WRN MS WILL BE CAPABLE OF SIGNIFICANT/DAMAGING TORNADOES.
   
   ..EDWARDS.. 04/27/2011
   
   
   ATTN...WFO...BMX...HUN...MEG...JAN...LZK...LCH...SHV...HGX...
   FWD...EWX...
   
   LAT...LON   31469634 31719491 32559316 33209172 34159156 34989006
               34988726 34428735 33798788 32318970 31309179 30469360
               30169607 30239710 31099745 31329702 31469634