MESOSCALE DISCUSSION 1003
   NWS STORM PREDICTION CENTER NORMAN OK
   0657 PM CDT MON JUN 04 2007
   
   AREAS AFFECTED...SRN TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 042357Z - 050130Z
   
   A SEVERE TSTM WATCH MAY BE NEEDED ACROSS PARTS OF SOUTH TX TONIGHT.
   ALTHOUGH PROBABLY NOT IMMINENT...AREA WILL BE MONITORED CLOSELY FOR
   ADDITIONAL STORM DEVELOPMENT IN THE NEXT FEW HOURS.
   
   VISIBLE SATELLITE IMAGERY AND OTHER OBSERVATIONAL DATA INDICATED A
   WEST TO EAST CLOUD BAND COINCIDENT WITH STRONG LOW LEVEL CONVERGENCE
   FROM DEL RIO AREA ACROSS SAN ANTONIO THIS EVENING. RECENT OUTFLOW
   BOUNDARY COLLISIONS ACROSS DEWITT AND WILSON COUNTIES EAST OF SAN
   ANTONIO HAVE AIDED RAPID AND INTENSE TSTM DEVELOPMENT IN THESE
   AREAS. MEANWHILE...VIGOROUS AND WIDESPREAD DEEP CONVECTION PERSISTS
   ACROSS THE MEXICAN MOUNTAINS TO THE SOUTH AND WEST OF THE RIO
   GRANDE. AIR MASS NEAR THE CONVERGENCE AXIS IS STRONGLY UNSTABLE AND
   35-40KT WLY FLOW ALOFT WAS CONTRIBUTING TO 30-40KT EFFECTIVE SHEAR.
   PRIMARY LIMITING FACTOR FOR WIDER COVERAGE ORGANIZED SEVERE STORM
   DEVELOPMENT APPEARS TO BE MODEST CONVECTIVE INHIBITION AND GENERALLY
   WEAK LARGE SCALE LIFT. HOWEVER...GIVEN MOST RECENT INITIATION NEAR
   OUTFLOW BOUNDARY INTERSECTIONS...IT IS CLEAR THAT CAP IS WEAK ENOUGH
   TO ALLOW RAPID AND ROBUST SUPERCELL DEVELOPMENT WHEN BREACHED.
   
   LATEST SHORT-TERM MODEL GUIDANCE IS OF LIMITED ASSISTANCE WITH MOST
   MODEL OUTPUT SHOWING VERY LITTLE DEVELOPMENT ACROSS SOUTH TX AREA
   THROUGH TONIGHT. EXPERIENTIAL HIGH RESOLUTION MODE OUTPUT ALSO
   SENDING MIXED SIGNALS SHOWING A VARIETY OF POSSIBLE SMALL MCS
   SCENARIOS...INCLUDING THE EWD PROPAGATION OF STORMS OFF THE MEXICAN
   ESCARPMENT ACROSS THE LOWER RIO GRANDE LATER TONIGHT. WITH STRONG
   FLOW PERSISTING ACROSS A REGION WITH ABUNDANT CAPE...AREA WILL
   CONTINUE TO BE MONITORED FOR ADDITIONAL DEVELOPMENT THIS EVENING AND
   A WATCH MAY BE NEEDED ON RELATIVELY SHORT NOTICE.
   
   ..CARBIN.. 06/04/2007
   
   
   ATTN...WFO...HGX...CRP...EWX...
   
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