MESOSCALE DISCUSSION 0555
   NWS STORM PREDICTION CENTER NORMAN OK
   0522 PM CDT SUN APR 24 2011
   
   AREAS AFFECTED...PORTIONS SW TX...EDWARDS PLATEAU AND ADJOINING RIO
   GRANDE VALLEY.
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 242222Z - 242345Z
   
   SVR POTENTIAL IS INCREASING ACROSS DISCUSSION AREA ALONG/E OF SFC
   DRYLINE.  LARGE HAIL WOULD BE PRIMARY THREAT...BUT SVR GUSTS AND A
   TORNADO OR TWO ALSO ARE POSSIBLE.  CONVECTIVE TRENDS ARE BEING
   MONITORED FOR PSBL WW.
   
   SFC MESOANALYSIS SHOWS DRYLINE EXTENDING FROM WRN FRINGES OF WW 196
   SWWD ACROSS PORTIONS IRION...NWRN CROCKETT...ERN PECOS AND TERRELL
   COUNTIES...THEN SSEWD PAST 6R6 INTO MEX MOUNTAINS W DRT.  VIS
   IMAGERY HAS BEEN INDICATING TRANSIENT CB AND FQT TCU OVER THOSE
   MOUNTAINS...IN PERSISTENT AREA OF OROGRAPHIC/UPSLOPE FLOW OF VERY
   MOIST/HIGH-THETAE AIR.  ANY SUSTAINED/RIGHT-MOVING TSTMS DEVELOPING
   FROM THAT REGIME MAY MOVE ESEWD AND REACH RIO GRANDE BEFORE
   WEAKENING.  ELONGATED HODOGRAPH SHAPE WITH SUBSTANTIAL NEGATIVE
   HELICITY FOR LEFT-SPLITS IS EVIDENT IN DFX VWP AND FCST SOUNDINGS
   NEAR RIO GRANDE...SUGGESTING POTENTIAL FOR LEFT-MOVERS WITH LARGE
   HAIL TO CROSS INTO TX.  ADDITIONAL TCU AND POTENTIAL TSTM
   DEVELOPMENT IS EVIDENT IN VIS IMAGERY OVER ERN PECOS
   COUNTY...CORRESPONDING TO WRN EXTENT OF PRONOUNCED MOIST-SECTOR
   BULGE ALONG DRYLINE.  MODIFIED DRT RAOB AND RUC SOUNDINGS SUGGEST
   CAP STRENGTHENING WITH SWD EXTENT ACROSS THIS AREA...SO CONVECTIVE
   COVERAGE/DURATION IS UNCERTAIN...ESPECIALLY FOR TSTMS EMANATING FROM
   SERRANIAS DEL BURRO RANGE.  LARGER POSITIVE SRH SHOULD REMAIN
   FARTHER N ACROSS WW 196...HOWEVER DEEP-LAYER SHEAR IS FCST TO
   STRENGTHEN AHEAD OF PROGRESSIVE SYNOPTIC-SCALE TROUGH OVER SWRN
   CONUS.  MEANWHILE LOW-LEVEL SHEAR SHOULD INCREASE NEAR SUNSET AS LLJ
   STRENGTHENS.  WITH STEEP LOW-MIDLEVEL LAPSE RATES ATOP SFC DEW
   POINTS 60S F...MLCAPE 3000-4000 J/KG SHOULD BE MAINTAINED FOR
   ANOTHER 2-3 HOURS...WITH ONLY SLOW DEVELOPMENT/INCREASE IN MLCINH
   AND DECREASE IN CAPE AFTER 01Z.
   
   ..EDWARDS.. 04/24/2011
   
   
   ATTN...WFO...CRP...EWX...SJT...MAF...
   
   LAT...LON   29850227 30760237 31430105 31090068 31089965 30370001
               29600033 28950013 28239983 28040003 28310030 28860060
               29270086 29560129 29600134 29690133 29770143 29760183
               29850227