MESOSCALE DISCUSSION 2045
   NWS STORM PREDICTION CENTER NORMAN OK
   1223 PM CDT SAT OCT 13 2012
   
   AREAS AFFECTED...BIG COUNTRY OF NWRN TX...SWRN OK
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 131723Z - 132000Z
   
   PROBABILITY OF WATCH ISSUANCE...80 PERCENT
   
   SUMMARY...TSTMS SHOULD INITIATE BY ABOUT 19Z ALONG THE COLD FRONT IN
   NWRN TX. THIS INITIAL ACTIVITY SHOULD LARGELY BE DISCRETE AND
   INTENSIFY THROUGH THE MID/LATE-AFTERNOON WITH SUPERCELL STRUCTURES
   LIKELY. PRIMARY INITIAL RISK SHOULD BE LARGE HAIL...BUT A COUPLE OF
   TORNADOES AND ISOLATED SEVERE WINDS ARE ALSO POSSIBLE.
   
   DISCUSSION...17Z SURFACE ANALYSIS PLACED A COLD FRONT FROM NEAR DDC
   TO CDS TO MAF. SW-NE ORIENTED BANDS OF CU WERE NOTED IN VISIBLE
   IMAGERY INVOF THE FRONT WITH THE MOST PRONOUNCED AGITATION OCCURRING
   NEAR CDS WHERE THE STRONGEST SURFACE HEATING HAS OCCURRED. MODIFIED
   12Z AMA/MAF RAOBS SUGGEST THIS REGION IS ALREADY LARGELY UNCAPPED
   WITH SURFACE TEMPERATURES HAVING WARMED INTO THE LOWER 80S. AS
   MID-LEVEL HEIGHT FALLS CONTINUE ACROSS THE REGION DOWNSTREAM OF THE
   SHORT WAVE TROUGH IN THE LEE OF THE SRN ROCKIES...TSTM INITIATION
   APPEARS PROBABLE IN THE NEXT HOUR OR SO.
   
   AS THE WARM SECTOR AIR MASS CONTINUES TO DESTABILIZE...ALBEIT WITHIN
   A RELATIVELY NARROW CORRIDOR GIVEN DOWNSTREAM WEAK CONVECTION ACROSS
   CNTRL OK...TSTMS ALONG THE FRONT WILL INTENSIFY. EFFECTIVE SHEAR OF
   AROUND 40-50 KT WILL FAVOR SUPERCELL STRUCTURES WITH LARGE HAIL AS
   THE PRIMARY THREAT. WHILE STRONGER LOW-LEVEL FLOW SHOULD LARGELY
   REMAIN E OF THE INITIAL FRONTAL DEVELOPMENT...A TORNADO OR TWO IS
   PLAUSIBLE WITH RELATIVELY LOW LCL HEIGHTS AND MODERATE 0-1 KM SRH.
   
   ..GRAMS/THOMPSON.. 10/13/2012
   
   
   ATTN...WFO...FWD...OUN...SJT...LUB...MAF...
   
   LAT...LON   35519954 35779913 35749858 35599833 35269825 34429834
               33179907 32309974 31800075 32190164 32790108 34449986
               35519954