MESOSCALE DISCUSSION 0428
   NWS STORM PREDICTION CENTER NORMAN OK
   0335 PM CDT THU APR 23 2015

   AREAS AFFECTED...CENTRAL TX

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 232035Z - 232230Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...THOUGH UNCERTAINTY PERSISTS...STORM DEVELOPMENT MAY OCCUR
   OVER THE NEXT COUPLE OF HOURS.  PRESUMING DEVELOPMENT...WW WOULD
   LIKELY BE REQUIRED.

   DISCUSSION...HIGH-LEVEL CIRRUS CLOUDS CONTINUE FLOWING
   ANTICYCLONICALLY NEWD ACROSS WRN AND CENTRAL TX THIS AFTERNOON...AS
   SHORT-WAVE RIDGING INCREASES ACROSS THE AREA DOWNSTREAM OF THE SRN
   STREAM SWRN U.S/NWRN MEXICO UPPER TROUGH.  WHILE A POCKET OF
   CLEARING OVER CENTRAL TX HAS ALLOWED SOME HEATING OF THE VERY MOIST
   BOUNDARY LAYER TO OCCUR /BOOSTING MIXED-LAYER CAPE VALUES ABOVE 2000
   J/KG/...CAPPING PREVAILS ATTM PER AMDAR SOUNDINGS AND AS IMPLIED BY
   LACK OF SURFACE-BASED CONVECTIVE DEVELOPMENT.

   WITH THAT SAID...CONTINUED LOCAL HEATING AND SOME INCREASE IN THE
   MID-LEVEL ACCAS DEPTH PER VISIBLE IMAGERY MAY BE THE FIRST SIGNS
   THAT STILL-UNCERTAIN SURFACE DEVELOPMENT MAY BE BECOMING MORE
   IMMINENT.  GIVEN THE MOIST/LOCALLY DESTABILIZING LOW-LEVEL AIRMASS
   AND BACKGROUND KINEMATIC ENVIRONMENT FEATURING FAVORABLE SHEAR FOR
   SUPERCELLS...WE WILL CONTINUE TO CLOSELY MONITOR THIS REGIONS FOR
   FURTHER SIGNS OF SURFACE-BASED CONVECTIVE INITIATION WHICH WOULD
   LIKELY REQUIRE WW ISSUANCE.

   ..GOSS/GRAMS.. 04/23/2015


   ATTN...WFO...HGX...FWD...EWX...SJT...

   LAT...LON   30189917 30519973 31079970 31999833 32209676 31449621
               30349695 30159830 30189917