MESOSCALE DISCUSSION 0303
   NWS STORM PREDICTION CENTER NORMAN OK
   0343 PM CDT WED APR 15 2015

   AREAS AFFECTED...PORTIONS SW TX -- BIG BEND REGION AND RIO GRANDE
   VALLEY DOWNSTREAM TO BETWEEN EAGLE PASS AND LRD.

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 152043Z - 152315Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...ISOLATED TO WIDELY SCATTERED TSTMS WILL AFFECT DISCUSSION
   AREA THROUGH EARLY EVENING...SOME OF WHICH MAY PRODUCE SVR HAIL
   AND/OR GUSTS.  WW DOES NOT APPEAR LIKELY ATTM.

   DISCUSSION...SFC MESOANALYSIS SHOWED DRYLINE EXTENDING FROM ERN
   PANHANDLE AND CAPROCK REGION E LBB...SWD IN DIFFUSE FASHION ACROSS
   CONCHO VALLEY REGION...THEN BENDING BACK WWD ACROSS TERRELL
   COUNTY...SWD TO SEWD AGAIN OVER BREWSTER COUNTY AND INTO WRN SLOPES
   OF SERRANIAS DEL BURRO RANGE IN COAHUILA.  DRYLINE SHOULD BE
   QUASISTATIONARY FOR ANOTHER COUPLE HOURS BEFORE RETREATING NWWD.

   STRONGLY MIXED BOUNDARY LAYER TO ITS W...AND RELATED HEATING OF
   HIGHER TERRAIN WITH MRGL BUT SUFFICIENT MOISTURE...HAS CONTRIBUTED
   TO DEVELOPMENT OF WIDELY SCATTERED TCU AND CB FROM DAVIS MTNS SWWD
   OVER NERN CHIHUAHUA AND SEWD TO AREAS OF MEX S OF BIG BEND.  THIS
   ACTIVITY WILL MOVE NEWD TO ENEWD INTO WELL-MIXED BOUNDARY LAYER ON
   EITHER SIDE OF DRYLINE...BUT WITH WEAK CAPE DUE TO LACK OF MORE
   ROBUST MOISTURE.  STILL...ISOLATED STG-SVR GUSTS MAY OCCUR.

   MOSTLY SEPARATE AREA OF DISCRETE CELLS HAS FORMED OVER SERRANIAS DEL
   BURRO RANGE ITSELF...SOME OF WHICH WILL MOVE GENERALLY EWD TOWARD
   RIO GRANDE VALLEY NEAR AND DOWNSTREAM FROM DRT.  PROSPECTIVE
   INFLOW-LAYER AIR MASS IS MORE MOIST THAN FARTHER NW...WITH SFC DEW
   POINTS MID 50S TO LOWER 60S F...INCREASING IN ANOTHER FEW HOURS TO
   MID-UPPER 60S S OF EAGLE PASS DUE TO MOIST ADVECTION.  THIS WILL
   SUPPORT 1500-2000 J/KG MLCAPE GENERALLY S OF HDO-DRT LINE. 
   EFFECTIVE-SHEAR MAGNITUDES INCREASE FROM AROUND 30 KT NW DRT TO 50
   KT OVER SRN PARTS OF COAHUILA...IN CLOSER PROXIMITY TO SUBTROPICAL
   JET.  MEANWHILE...FCST INCREASE IN 850-900-MB SELYS NEAR 00Z WILL
   BOOST STORM-RELATIVE LOW-LEVEL WINDS.  AS SUCH...POTENTIAL EXISTS
   FOR A FEW ORGANIZED TSTMS...PERHAPS INCLUDING A SUPERCELL...TO REACH
   AND CROSS RIO GRANDE...OFFERING LARGE HAIL AND STG-SVR GUSTS. 
   CONCERNS REGARDING STORM COVERAGE AND DURATION INTO HIGHER-CINH AIR
   MASS E OF A UVA-LRD LINE PRECLUDE NEED FOR WW ATTM.  HOWEVER
   CONVECTIVE TRENDS WILL BE MONITORED FOR ANY SUITABLE UPSCALE
   ORGANIZATION OR COLD-POOL POTENTIAL.

   ..EDWARDS/THOMPSON.. 04/15/2015


   ATTN...WFO...CRP...EWX...MAF...

   LAT...LON   27869987 28150007 28230027 28890058 29080066 29160078
               29260078 29370100 29520124 29750139 29760172 29780207
               29890230 29740235 29720265 29340281 29320288 29210286
               29160298 29100310 28970310 29040336 29210358 29890363
               30730334 30320214 30060158 29850074 29720012 29109971
               28329973 27869987