MESOSCALE DISCUSSION 2189
   NWS STORM PREDICTION CENTER NORMAN OK
   0359 PM CDT SUN SEP 18 2011
   
   AREAS AFFECTED...NRN/CNTRL TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 182059Z - 182130Z
   
   THUNDERSTORM DEVELOPMENT IS POSSIBLE OVER PORTIONS OF NRN/CNTRL TX
   DURING THE NEXT FEW HRS. ENVIRONMENT SUPPORTS SVR STORMS POSING A
   THREAT OF LARGE HAIL AND DAMAGING WINDS. WW IS LIKELY.
   
   AT 20Z...SURFACE COLD FRONT EXTENDED SWWD FROM NERN OK INTO PORTIONS
   OF CNTRL TX. RECENT VIS SATELLITE IMAGERY SHOWS GENERALLY FLAT CU
   FIELD ALONG/AHEAD OF THE FRONT...WITH THE EXCEPTION OF A FEW
   TOWERING CUMULUS NEAR THE RED RIVER. THOUGH BOUNDARY LAYER HAS
   SLOWLY DESTABILIZED DURING THE AFTERNOON...UPPER VORT LOBE IS
   SITUATED IMMEDIATELY ABOVE THE REGION...LEADING TO NEGLIGIBLE
   LARGE-SCALE ASCENT. THUS...THUNDERSTORM INITIATION AND SUBSEQUENT
   COVERAGE IS UNCERTAIN ATTM DURING THE SHORT TERM.
   NEVERTHELESS...ENVIRONMENT IS QUITE MOIST AND UNSTABLE...WITH MLCAPE
   VALUES NEAR 2500 J/KG. THIS INSTABILITY COMBINED WITH MODEST
   VERTICAL SHEAR PROFILES WOULD BE SUFFICIENT FOR SVR MULTICELL
   THUNDERSTORMS...POSING A LARGE HAIL AND DAMAGING WIND THREAT. GIVEN
   RECENT TRENDS IN VIS SATELLITE IMAGERY...AREA MAY REQUIRE A WW
   DURING THE NEXT HR.
   
   ..GARNER.. 09/18/2011
   
   
   ATTN...WFO...SHV...TSA...FWD...OUN...EWX...SJT...
   
   LAT...LON   31700069 33189925 33989738 33939504 32609508 30859835
               30730024 31700069