severe storms evening potential

   MESOSCALE DISCUSSION 0488    NWS STORM PREDICTION CENTER NORMAN OK    0731 PM CDT THU APR 16 2009        AREAS AFFECTED...SWRN TX        CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE         VALID 170031Z - 170200Z        TSTM POTENTIAL APPEARS TO BE INCREASING ACROSS SRN PORTION OF    TORNADO WATCH 157 SWD TO THE RIO GRANDE.  SHOULD STORMS DEVELOP S OF    WW...A LOCAL EXTENSION IN AREA MAY BE REQUIRED.  SHOULD STORMS    DEVELOP AND CROSS THE RIO GRANDE NEAR DRT...A NEW WW WOULD BE    REQUIRED.        LATEST VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE    DRYLINE RETREATING WWD THROUGH ECTOR...CRANE...PECOS AND BREWSTER    COUNTIES...TO THE E OF PACIFIC COLD FRONT ADVANCING EWD THROUGH FAR    WRN TX.  EXTRAPOLATION OF CURRENT MOTION SUGGESTS A MERGING OF THESE    BOUNDARIES OVER LOVING OR WINKLER SWD INTO WARD...REEVES...PECOS AND    BREWSTER COUNTIES WITHIN THE NEXT 1-2 HOURS.  BASED ON 00Z MAF/DRT    SOUNDINGS...THERMODYNAMIC ENVIRONMENT REMAINS MODERATELY UNSTABLE    THIS EVENING OWING TO THE PRESENCE OF STEEP LAPSE RATES AND    INCREASING BOUNDARY LAYER MOISTURE.        WHILE THE CAPPING EML INCREASES WITH SWD EXTENT TOWARD THE RIO    GRANDE...ENHANCED MESOSCALE CONVERGENCE ALONG THESE COLLIDING    BOUNDARIES MAY BE SUFFICIENT TO INITIATE ADDITIONAL STORMS...PERHAPS    IN THE FORM OF A LINE.  SHOULD THIS OCCUR...AN AREAL EXTENSION OF WW    157 MAY BE REQUIRED.        FARTHER SE...TSTMS ARE ATTEMPTING TO BECOME SUSTAINED ALONG THE    HIGHER TERRAIN W OF DRT AS OF 0020Z.  00Z DRT SOUNDING WAS RATHER    IMPRESSIVE WITH AN MLCAPE OF 2500 J/KG...0-1 KM SHEAR OF 25-30 KT    AND DEEP-LAYER SHEAR OF 50-60 KT.  AS MENTIONED ABOVE...A STRONG CAP    WAS OBSERVED AROUND 800 MB SO THERE IS SOME QUESTION IF DEVELOPING    STORMS WILL BECOME SUSTAINED AS THEY MOVE OFF THE HIGHER TERRAIN    INTO THE RIO GRANDE VALLEY.  GIVEN THE ENVIRONMENT VERY CONDUCIVE TO    SUPERCELLS...A WW WOULD HAVE TO BE CONSIDERED IF ANY STORMS CAN    DEVELOP AND MOVE TOWARD DRT.        ..MEAD.. 04/17/2009            ATTN...WFO...EWX...SJT...MAF...        LAT...LON   29870330 30750333 31300318 31610287 31020210 30220151                29890062 29290030 29180067 29570118 29830185 29570307                29870330