MESOSCALE DISCUSSION 0606
   NWS STORM PREDICTION CENTER NORMAN OK
   0759 PM CDT TUE APR 26 2011
   
   AREAS AFFECTED...PORTIONS NERN LA...EXTREME SERN AR...NRN MS...NWRN
   AL...MIDDLE TN.
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 270059Z - 270300Z
   
   WW 215 HAS BEEN EXTENDED EWD ACROSS REMAINDER NRN MS AND WRN TN. 
   ADDITIONAL OR REPLACEMENT WW ISSUANCE MAY BE REQUIRED WITHIN NEXT 2
   HOURS ACROSS PORTIONS OF DISCUSSION AREA...PERHAPS INCLUDING AREAS
   CURRENTLY IN WW 215 THAT WILL STILL CONTAIN FAVORABLE BUOYANCY/SHEAR
   ENVIRONMENT.
   
   POCKET OF RELATIVELY LOW-THETAE SFC AIR WITH DEW POINTS LOW-MID 60S
   F IS EVIDENT ATTM FROM NRN MS NEWD OVER MID TN AND SWD ACROSS NRN
   AL.  HOWEVER...STG LOW-LEVEL MOIST/WARM ADVECTION IS
   FCST...ESPECIALLY JUST ABOVE SFC.  LLJ IS FCST TO STRENGTHEN TO
   50-65 KT RANGE ACROSS BROAD SWATH OF LOWER DELTA REGION INTO MID TN
   THROUGH 06Z.  ACCORDINGLY MODIFIED JAN/SHV RAOBS AND RUC FCST
   SOUNDINGS SUGGEST CURRENTLY STRONG MLCINH OVER NRN MS WILL
   WEAKEN...WHILE MLCAPE INCREASES REGION-WIDE TO 2000-2500 J/KG VALUES
   NOW EVIDENT OVER WRN TN AND SRN MS.  AS MID-UPPER TROUGHING DEEPENS
   ACROSS OK...MID-UPPER LEVEL WIND PROFILES WILL STRENGTHEN OVER THIS
   AREA ALSO...WITH 55-60 KT EFFECTIVE SHEAR MAGNITUDES BECOMING
   COMMON.  LLJ ALSO WILL ENLARGE LOW-LEVEL HODOGRAPHS WITH 0-1 KM SRH
   REACHING 300-500 J/KG RANGE.  NET RESULT SHOULD BE EWD  SHIFT/SPREAD
   OF TORNADIC SUPERCELL REGIMES NOW OVER ARKLATEX REGION AND SWRN
   TN/NWRN MS.  DEVELOPMENT OF SVR BOW ECHOES WITH ENHANCED DAMAGING
   WIND THREAT ALSO MAY OCCUR...GIVEN STRENGTH AND ANGLE OF DEEP-LAYER
   WIND WITH RESPECT TO CONVECTIVE FORCING...AND CLOSE PROXIMITY OF
   CONVECTION ALREADY EVIDENT.
   
   ..EDWARDS.. 04/27/2011
   
   
   ATTN...WFO...OHX...BMX...HUN...MEG...JAN...SHV...
   
   LAT...LON   31399192 33049209 33689067 34738886 35538813 36558700
               36238615 35188651 33818768 32678981 31399192