MESOSCALE DISCUSSION 1918
   NWS STORM PREDICTION CENTER NORMAN OK
   0501 PM CDT TUE AUG 09 2011
   
   AREAS AFFECTED...PORTIONS TX PANHANDLE AND SOUTH-PLAINS REGION EWD
   ACROSS SRN OK AND N TX.
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 092201Z - 092300Z
   
   WIDELY SCATTERED TO SCATTERED TSTMS SHOULD DEVELOP ALONG BOUNDARY
   DESCRIBED BELOW...WITH POTENTIAL FOR DAMAGING GUSTS FROM MOST
   INTENSE CELLS. WILL CONTINUE TO MONITOR FOR SIGNS OF UPSCALE
   COLD-POOL AGGREGATION FROM STORM-SCALE PROCESSES THAT MAY BOLSTER
   LONGEVITY.
   
   21Z SFC MESOANALYSIS SHOWS OUTFLOW BOUNDARY --LEFT BY PRIOR
   OVERNIGHT/MORNING CONVECTION IN OK/AR -- FROM NEAR JAN TO DEQ TO
   ARBUCKLES OF SRN OK...THEN SWWD ACROSS SPS AREA...THEN ARCHING
   WWD/NWD OVER FOARD/BRISCOE/POTTER COUNTIES TX.  SEGMENT OF BOUNDARY
   W OF ABOUT 100W IS MOVING NWD 5-10 KT...WHILE REMAINDER OVER
   DISCUSSION AREA SHOULD REMAIN QUASISTATIONARY THROUGH EARLY EVENING.
   MOIST AXIS IS ANALYZED FROM SERN PANHANDLE ACROSS CENTRAL OK TO NEAR
   FSM...CHARACTERIZED BY SFD DEW POINTS MID-UPPER 50S IN PANHANDLE TO
   70S ACROSS CENTRAL-ERN OK.  SATELLITE IMAGERY AND DIRECT VISUAL
   OBSERVATION SHOW BAND OF RELATIVELY DEEP TOWERS...A FEW OF WHICH
   HAVE GLACIATED BRIEFLY SO FAR...ACROSS S-CENTRAL OK ALONG
   BOUNDARY..AND OVER LOVE/COOKE COUNTIES ASTRIDE RED RIVER INVOF
   MESOBETA SCALE CONFLUENCE AXIS.  DEEPER CONVECTION -- INCLUDING
   ISOLATED TSTMS -- ALREADY HAS FORMED INVOF BOUNDARY OVER
   PANHANDLE...WITH SCATTERED TSTMS ALONG SEPARATE CONVERGENCE BOUNDARY
   FROM MOORE COUNTY TX TO SERN CHAVES COUNTY NM.  RELATIVE MIN IN
   CONVECTIVE COVERAGE/DEPTH SO FAR...BETWEEN SPS AREA AND SERN
   PANHANDLE...APPEARS RELATED TO WEAKER CONVERGENCE ASSOCIATED WITH
   DIFLUENT SFC-850 MB WINDS IN WARM SECTOR...AS OBSERVED IN
   SFC/VWP/PROFILER DATA.  STILL...ISOLATED TSTMS MAY DEVELOP ALONG
   THAT SEGMENT OF BOUNDARY AS WELL...BEFORE PANHANDLE CONVECTION MOVES
   INTO REGION.  TSTMS FORMING OVER SRN OK SHOULD MOVE SEWD OVER
   PORTIONS N-CENTRAL/NE TX INTO FAVORABLE BOUNDARY LAYER.
   
   THROUGH EARLY EVENING...AIR MASS S OF OUTFLOW AND E OF WRN
   CONVECTIVE BAND WILL REMAIN CHARACTERIZED BY HOT/DEEPLY-MIXED
   SUBCLOUD LAYERS CONDUCIVE FOR ACCELERATING DOWNDRAFT GUSTS VIA
   EVAPORATIVE COOLING.  FLOW ALOFT IS RELATIVELY WEAK...YIELDING NELY
   EFFECTIVE SHEAR VECTORS ONLY ABOUT 20 KT LONG.  THIS SHOULD BE
   SUFFICIENT FOR ACTIVITY TO MOVE SWD OVER N TX INTO AIR MASS
   CHARACTERIZED BY 500-1000 J/KG MLCAPE...LOCALLY HIGHER...BASED ON
   MODIFIED RUC SOUNDINGS...AND 1500-2500 J/KG DCAPE.  VALUES OF EACH
   DECREASE EWD ACROSS NW TX...BUT STILL APPEAR FAVORABLE ENOUGH FOR
   WIND DAMAGE THREAT FROM ANY PANHANDLE CONVECTION MOVING SEWD OVER
   AREA.
   
   ..EDWARDS.. 08/09/2011
   
   
   ATTN...WFO...SHV...TSA...FWD...OUN...SJT...LUB...AMA...
   
   LAT...LON   34000293 35500243 35810152 35180036 34719866 34609662
               34559544 33919450 33039459 32519609 32659743 33209972
               33450143 33490287 34000293