MESOSCALE DISCUSSION 2349
   NWS STORM PREDICTION CENTER NORMAN OK
   0346 PM CST MON NOV 21 2011
   
   AREAS AFFECTED...CNTRL INTO NERN TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 212146Z - 212345Z
   
   THE THREAT FOR SVR THUNDERSTORMS COULD INCREASE DURING THE NEXT FEW
   HOURS FROM CNTRL INTO NERN TX...AND THIS AREA WILL BE MONITORED FOR
   THE POSSIBLE ISSUANCE OF A WW.
   
   VISIBLE SATELLITE IMAGERY AND SFC OBS INDICATE A STRONG FRONT SLOWLY
   RETREATING NWD OVER PORTIONS OF CNTRL/ERN TX...WITH MLCAPE VALUES OF
   1000-1500 J/KG SOUTH OF THE BOUNDARY. THIS IS OCCURRING AS
   INCREASING MID-LEVEL HEIGHT FALLS AHEAD OF A PAIR OF APPROACHING
   SHORTWAVE TROUGHS INDUCE SFC PRESSURE FALLS OF 3 TO 4 MB PER 2 HRS
   NORTH OF THE BOUNDARY. LITTLE IN THE WAY OF CONVECTION HAS BEEN
   NOTED NEAR OR SOUTH OF THE BOUNDARY THUS FAR...OWING TO WEAK
   VELOCITY CONVERGENCE ALONG THE FRONT...WITH THE STRONGEST DEEP-LAYER
   ASCENT AND ASSOCIATED CONVECTION FARTHER N ACROSS N-CNTRL TX NWD
   INTO OK. HOWEVER...AS THE MID-LEVEL TROUGHS MAKE ADDITIONAL EWD
   PROGRESS...THUNDERSTORMS COULD DEVELOP LATER THIS AFTERNOON.
   EFFECTIVE BULK SHEAR MAGNITUDES OF 50-55 KT WILL CONDITIONALLY
   PROMOTE A THREAT FOR SUPERCELLS...WITH SVR HAIL THE PRIMARY CONCERN.
   HOWEVER...ANY STORMS THAT ARE ABLE TO INTERACT WITH THE FRONT AS IT
   LIFTS NWD...OR EVOLVE WITHIN THE WARM SECTOR...WILL ALSO BE CAPABLE
   OF PRODUCING DMGG WIND GUSTS...AND POSSIBLY A TORNADO.
   HOWEVER...WEAKENING LOW-LEVEL SRH WITH SWD DISPLACEMENT FROM THE
   BOUNDARY PER VWP DATA SUGGESTS THAT ANY TORNADO THREAT...ALBEIT
   MINIMAL...WILL BE CONFINED TO A NARROW CORRIDOR ALONG THE SFC FRONT.
   GIVEN THE UNCERTAINTY IN CONVECTIVE INITIATION/COVERAGE...THE NEED
   FOR A WW IS UNCERTAIN. HOWEVER...TRENDS WILL CONTINUE TO BE
   MONITORED FOR POTENTIAL WW ISSUANCE.
   
   ..COHEN.. 11/21/2011
   
   
   ATTN...WFO...SHV...HGX...FWD...EWX...
   
   LAT...LON   32549426 31779511 30729647 30499754 31249806 32399779
               33139713 33549631 33699554 33679486 33239424 32549426