MESOSCALE DISCUSSION 1624
   NWS STORM PREDICTION CENTER NORMAN OK
   1048 AM CDT MON JUL 20 2009
   
   AREAS AFFECTED...CNTRL TX
   
   CONCERNING...OUTLOOK UPGRADE 
   
   VALID 201548Z - 201715Z
   
   ONGOING TSTMS ARE EXPECTED TO ORGANIZE INTO A SWD-MOVING MCS TODAY
   WITH THE THREAT FOR DAMAGING WINDS AND SOME HAIL.  PARTS OF AREA
   WILL BE UPGRADED TO A SLIGHT RISK AT 1630Z.
   
   TSTMS WHICH INITIATED EARLIER THIS MORNING OVER WRN OK/NWRN TX ARE
   ONGOING AS OF 1530Z WITH THE MOST INTENSE ACTIVITY FOCUSED IN A N-S
   BAND FROM CLAY TO BROWN AND MCCULLOCH COUNTIES.  ANOTHER STRONG
   STORM CLUSTER WAS LOCATED OVER ELLIS COUNTY.  REGIONAL VWP/PROFILER
   DATA INDICATE THAT LOWER TROPOSPHERIC WAA IS LARGELY FORCING THIS
   CONVECTION ALONG 20-30 KT SWLY LLJ AXIS.  WHILE LLJ WILL UNDERGO
   DIURNAL WEAKENING...12Z MODEL GUIDANCE SUGGESTS THAT AT LEAST MODEST
   SLY LOW-LEVEL FLOW WILL CONTINUE TODAY ACROSS DISCUSSION
   AREA...MAINTAINING WAA REGIME GIVEN NNWLY MID/HIGH-LEVEL WIND
   FIELDS.
   
   12Z OBSERVED SOUNDING DATA INDICATE THAT ONGOING TSTM CLUSTER
   RESIDES ALONG ERN FRINGE OF STEEPER MIDLEVEL LAPSE RATES SITUATED
   OVER THE ROCKIES AND ADJACENT HIGH PLAINS.  WHEN COUPLED WITH
   DAYTIME HEATING AND MOIST BOUNDARY LAYER CONDITIONS /DEWPOINTS OF
   70-75F/...AIR MASS IS EXPECTED TO BECOME MODERATELY UNSTABLE WITH
   MLCAPE INCREASING TO 1500-2500 J/KG.  AS SUCH...EXPECT TSTMS TO
   GRADUALLY INTENSIFY INTO AN ORGANIZED MCS WHICH WILL MOVE/PROPAGATE
   SWD.  LOCALLY DAMAGING WIND GUSTS WILL BE THE PRIMARY SEVERE THREAT
   THOUGH SOME HAIL WILL ALSO BE POSSIBLE.
   
   ..MEAD.. 07/20/2009
   
   
   ATTN...WFO...HGX...FWD...EWX...SJT...
   
   LAT...LON   30129978 30879941 31389884 31769785 32079708 32089668
               31709623 31129628 30089676 29419724 29079828 29439929
               30129978