MESOSCALE DISCUSSION 0751
   NWS STORM PREDICTION CENTER NORMAN OK
   1125 PM CDT WED MAY 11 2011
   
   AREAS AFFECTED...EAST-CENTRAL/SOUTH-CENTRAL TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 120425Z - 120530Z
   
   AT LEAST AN ISOLATED SEVERE THREAT WILL LIKELY CONTINUE
   OVERNIGHT...AND A NEW WATCH WILL NEED TO BE CONSIDERED FOR PORTIONS
   OF SOUTH-CENTRAL/PERHAPS EAST-CENTRAL TX.
   
   AN ONGOING SEVERE TSTM NEARING I-35 BETWEEN NEW BRAUNFELS/AUSTIN AS
   OF 0415Z HAS EXHIBITED SOME SUPERCELL CHARACTERISTICS OVER THE PAST
   HOUR. SIMILAR TO THIS STORM...IT IS CONCEIVABLE THAT ADDITIONAL
   SURFACE BASED DEVELOPMENT WILL CONTINUE TO OCCUR ALONG A SOUTHEAST
   SAGGING OUTFLOW BOUNDARY WITHIN A RATHER MOIST AND WEAKLY
   CAPPED/VERY UNSTABLE AIRMASS...WITH CINH EXPECTED TO ONLY WEAKEN
   OVERNIGHT PER SHORT TERM PROGS. WSR-88D VWP DATA FROM EWX/GRX
   REFLECT AMPLE VEERING/WIND SPEEDS FOR UPDRAFT
   ROTATION/SUPERCELLS...ACCENTUATED BY 150-200 M2/S2 0-1 KM
   SRH...WHICH IMPLIES A BRIEF TORNADO CANNOT BE RULED OUT IN VICINITY
   OF THE SURFACE BOUNDARY ASIDE FROM LARGE HAIL.
   ADDITIONALLY...VARIOUS NUMERICAL GUIDANCE...SUCH AS THE 00Z NAM/GFS
   AND VARIOUS 21Z SREF MEMBERSHIP...IMPLY AN EAST-SOUTHEASTWARD
   CONTINUATION OF DEEP CONVECTION TOWARD THE MIDDLE/UPPER TX
   COAST...AND/OR MORE SO THE POSSIBILITY OF ADDITIONAL DEVELOPMENT
   LATE TONIGHT/EARLY THURSDAY IN VICINITY OF THE RIO GRANDE.
   
   ..GUYER.. 05/12/2011
   
   
   ATTN...WFO...HGX...FWD...EWX...
   
   LAT...LON   30959736 31739650 31629574 29279573 28800030 29810021
               30359783 30959736