MESOSCALE DISCUSSION 1616
   NWS STORM PREDICTION CENTER NORMAN OK
   0258 AM CDT SUN JUL 19 2009
   
   AREAS AFFECTED...TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 190758Z - 191000Z
   
   TSTMS HAVE ERUPTED AND BECOME QUITE NUMEROUS OVER PARTS OF THE TX
   PNHDL AND TX SOUTH PLAINS OVER THE PAST COUPLE OF HOURS. ONE OR TWO
   OF THE STRONGER UPDRAFTS MAY BE PRODUCING HAIL IN EXCESS OF ONE INCH
   IN DIAMETER BASED ON OBJECTIVE DATA AND COMPOSITE MESH/RADAR TRENDS.
   THIS DEVELOPMENT WAS LIKELY IN RESPONSE TO AN INCREASE IN LARGE
   SCALE FORCING FOR ASCENT ASSOCIATED WITH A SHORT WAVE TROUGH AND
   40-50KT MID LEVEL SPEED MAX SPREADING SSEWD ACROSS THE OK/TX PNHDLS
   AT THIS TIME. LARGER SCALE QG DYNAMICS APPEAR TO BE ACTING UPON A
   MESOSCALE REGIME/PATTERN ACROSS THE REGION THAT SHOULD REMAIN
   CONDUCIVE TO SCATTERED VIGOROUS CONVECTIVE DEVELOPMENT EARLY TODAY.
   
   AS MOIST LOW LEVEL SELY/UPSLOPE FLOW CONTRIBUTES TO BOTH INSTABILITY
   AND PRONOUNCED EFFECTIVE SHEAR ACROSS THE AREA...MESOSCALE LIFT
   AIDING TSTM DEVELOPMENT APPEARS TO BE FOCUSED NEAR WARM
   FRONT/RESIDUAL COLD POOL INTERSECTION AND INVERTED SFC TROUGH
   SITUATED ACROSS WEST TX. JAYTON PROFILER DEPICTS THE PRONOUNCED WAA
   REGIME LIKELY AIDING THE ONGOING DEVELOPMENT THAT IS NOW SPREADING
   SWD IN EXPANDING N-S BANDS/CLUSTERS. OBJECTIVE DATA ALSO DEPICT
   STRONG UPPER LEVEL DIFFLUENT FLOW AND ANVIL LEVEL SR WINDS IN EXCESS
   OF 80KT THUS SUPPORTING MASS EVACUATION AT UPPER LEVELS.
   
   WHILE CURRENT DIAGNOSES EXPLAINS THE DEVELOPMENT OF THE CONVECTION
   AND POTENTIAL FOR SOME HAIL...LONGER-TERM EVOLUTION INTO A MORE
   WIDESPREAD SEVERE THREAT...INCLUDING ANY INCREASE IN DAMAGING WIND
   HAZARDS...IS SOMEWHAT UNCERTAIN. LACK OF STRONG LOW LEVEL
   CYCLOGENESIS...AND GENERALLY LIMITED ONGOING ORGANIZATION BUT
   WIDESPREAD DEVELOPMENT MAY COMPLICATE UPSCALE MCS PROCESSES.
   HOWEVER...IF STRONGER UPDRAFTS PERSIST AND MERGE INTO LARGER MORE
   ORGANIZED MASS THAT BEGINS TO EXHIBIT DAMAGING WIND AND MORE
   WIDESPREAD LARGE HAIL THREAT...A SEVERE TSTM WATCH MAY BE NEEDED
   OVER AREAS OF WEST TX BEFORE DAYBREAK.
   
   ..CARBIN.. 07/19/2009
   
   
   ATTN...WFO...OUN...EWX...SJT...LUB...MAF...
   
   LAT...LON   34640065 33949985 32809936 30609945 30150070 30560150
               32060144 32660146 34080189 34640065