MESOSCALE DISCUSSION 0612
   NWS STORM PREDICTION CENTER NORMAN OK
   0513 AM CDT SUN APR 29 2007
   
   AREAS AFFECTED...PORTIONS SW TX -- BIG BEND/LOWER
   PECOS...TRANS-PECOS AND PERMIAN BASIN REGIONS.
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 291013Z - 291215Z
   
   CORRECTED FOR TYPO
   
   INCREASING CONVECTIVE COVERAGE AND INTENSITY IS EXPECTED ACROSS THIS
   REGION THROUGH MIDMORNING...WITH OCCASIONAL LARGE HAIL POSSIBLE.
   
   SFC MESOANALYSIS SHOWS WARM FRONT MOVING SLOWLY NWD TOWARD I-10
   CORRIDOR BETWEEN JCT-FST...BENEATH 25-35 KT LLJ.  RELATED SFC THETAE
   ADVECTION AND MOIST ADVECTION ABOVE SFC WILL BOOST BUOYANCY FROM
   S-N...SUPPORTING BOTH TSTMS MOVING NWD FROM MEX AND ACTIVITY
   DEVELOPING N OF RIO GRANDE.  THIS REGION WILL REMAIN IN ZONE OF
   STRONG UPPER LEVEL DIFLUENCE NE OF UPPER LOW LOCATED INVOF
   SONORA/CHIHUAHUA BORDER.  WITH LITTLE MOVEMENT EXPECTED OF UPPER
   VORTEX DURING NEXT SEVERAL HOURS...MID/UPPER LEVEL WINDS AND
   THEREFORE DEEP-LAYER BULK SHEAR WILL WEAKEN SUBSTANTIALLY WITH NWD
   EXTENT.  THIS FACTOR...ALONG WITH DIMINISHING INSTABILITY NWD ACROSS
   PERMIAN BASIN TOWARD S PLAINS...WILL LIMIT SVR POTENTIAL NEAR AND N
   OF I-20 THROUGH MIDMORNING.  EXPECT SFC-BASED EFFECTIVE INFLOW
   PARCELS WITH MLCAPES 1000-1500 J/KG ALONG RIO GRANDE...DROPPING TO
   LESS THAN 500 J/KG ALONG WARM FRONT...THOUGH ELEVATED MUCAPES
   500-1000 J/G MAY SUSTAIN ACTIVITY FOR 50-80 NM N OF WARM FRONT
   BEFORE WEAKENING. BULK SHEAR SHOULD REMAIN MAXIMIZED OVER BIG BEND
   AND SWRN TRANS-PECOS AREAS NEAR RIO GRANDE...WITH 0-6 KM VALUES
   35-40 KT.
   
   ..EDWARDS.. 04/29/2007
   
   
   ATTN...WFO...EWX...SJT...MAF...EPZ...
   
   31130566 31380201 31020068 30220045 28920061 29740140
   29770173 29850230 29730259 28970311 29280395 29600445
   29880463 30180467 30660502 30810522