MESOSCALE DISCUSSION 0313
   NWS STORM PREDICTION CENTER NORMAN OK
   1015 PM CDT TUE MAR 29 2011
   
   AREAS AFFECTED...PORTIONS S TX...SWRN/S-CENTRAL LA.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 73...75...
   
   VALID 300315Z - 300445Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   73...75...CONTINUES.
   
   CONTINUE WW 73.  WW 75 IS SLATED TO EXPIRE AT 04Z...HOWEVER SRN
   PORTIONS MAY NEED TO BE REPLACED BEFORE THEN...PENDING ADDITIONAL
   SCRUTINY OF CONVECTIVE/ENVIRONMENTAL TRENDS.
   
   ISOLATED...APPARENTLY SVR TSTM WITH INTERMITTENT SUPERCELLULAR
   MORPHOLOGY...WHICH DEVELOPED ALONG ERN SLOPES OF SERRANIAS DEL BURRO
   RANGE IN MEX...IS AFFECTING EAGLE PASS AREA ATTM.  THIS
   ACTIVITY...ALONG WITH OTHER CONVECTION DEVELOPING TO ITS SE AND
   SW...MAY GROW UPSCALE AND PERSIST FOR A FEW MORE HOURS...MOVING
   ESEWD IN STEP WITH SFC COLD FRONT.  FOREGOING AIR MASS WILL BE
   CHARACTERIZED BY MLCAPE 1000-2000 J/KG MLCAPE AND 45-55 KT EFFECTIVE
   SHEAR MAGNITUDES.  WEAK LOW-LEVEL WINDS WILL CONTINUE TO LIMIT
   NEAR-SFC HODOGRAPH SIZE.  FRONTAL MAX IN LOW-LEVEL ASCENT WILL HELP
   TO OVERCOME WHAT SHOULD BE GRADUAL INCREASE WITH TIME IN MLCINH IN
   PROSPECTIVE INFLOW REGION...CASTING CONSIDERABLE UNCERTAINTY AS TO
   HOW LONG THIS ACTIVITY WILL LAST.  TYPICALLY...SUCH COMPLEXES IN
   THIS AREA AND IN SIMILAR REGIMES PRODUCE SVR ALONG WELL-DEFINED
   SWATH...BUT OFTEN DISSIPATE ABRUPTLY AMIDST AMBIENT STRENGTHENING OF
   BOUNDARY-LAYER CAPPING.  RELATIVE WEAKNESS IN MLCINH CURRENTLY
   EVIDENT N OF CRP-LRD LINE INDICATES CONVECTION MAY PERSIST ACROSS
   MUCH OF PROJECTED PATH TOWARD COAST...THEREFORE SMALL WW MAY BE
   REQUIRED.  SVR THREAT FROM ISOLATED/POSTFRONTAL/LEFT-MOVING TSTM
   NEAR DRT SHOULD BE MORE TRANSIENT/ISOLATED.
   
   MEANWHILE...STG-SVR TSTMS ARE INCREASING SUBSTANTIALLY IN COVERAGE
   OVER ERN PORTIONS WW 75...ACROSS SERN LA...WITH SIMILAR TRENDS
   POSSIBLE OVER PORTIONS SE TX AS WELL.  COLD FRONT -- ANALYZED AT 03Z
   FROM EAGLE PASS STORM ENEWD OVER ATASCOSA/HARRIS/NEWTON COUNTIES TX
   AND VERNON PARISH LA -- WILL KEEP MOVING SEWD ABOUT 20 KT ACROSS
   THIS REGION...PROVIDING PRIMARY FOCUS FOR CONVECTIVE DEVELOPMENT SFC
   AND ALOFT.
   
   ..EDWARDS.. 03/30/2011
   
   
   ATTN...WFO...JAN...LCH...SHV...HGX...CRP...EWX...BRO...
   
   LAT...LON   29280088 29590042 29569818 30699450 31519266 31419187
               29469186 29589214 29519228 29569270 29769323 29739379
               29659380 29649412 29479460 28919529 28449628 27949695
               27239736 27319958 27399946 27569953 27659974 27799988
               28140007 28390036 29110068 29280088