MESOSCALE DISCUSSION 0754
   NWS STORM PREDICTION CENTER NORMAN OK
   0246 PM CDT TUE MAY 08 2007
   
   AREAS AFFECTED...A LARGE PORTION OF NRN AND CENTRAL
   TX...SCENTRAL/SERN OK
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 081946Z - 082215Z
   
   ISOLATED DISCRETE SVR STORMS MAY FORM ALONG AND NORTH OF AN OUTFLOW
   BOUNDARY EXTENDING WSW-ENE ACROSS NWRN/NCENTRAL TX IN THE NEXT 2-4
   HOURS. IF ANY SVR TSTMS DO DEVELOPS OVER NWRN/NCENTRAL TX STORM
   MOTIONS WILL EVENTUALLY TAKE A SVR THREAT INTO SCENTRAL/SERN OK.
   ADDITIONAL SVR CONVECTIVE LINE OVER WRN TX IS EXPECTED TO MOVE EAST
   OF WW 257 AND INTO CENTRAL TX AFTER 22Z AND MAY CONTINUE TO POSE A
   SVR WIND THREAT. THE ENTIRE AREA IS BEING MONITORED FOR A POSSIBLE
   WW BY 22Z.
   
   LATEST VISIBLE SAT IMAGERY INDICATED STRONG HEATING WAS OCCURRING
   OVER NRN TX AND SRN OK IN THE WAKE OF AN MORNING MCS OVER OK AND
   AHEAD OF ANOTHER MCS OVER WRN TX. SFC ANALYSIS SHOWS TEMPERATURES
   HAVE WARMED INTO THE LOWER 80S ALONG AND JUST SOUTH OF AN OUTFLOW
   BOUNDARY EXTENDING FROM NEAR ABI TO NORTH OF THE DFW METRO AREA.
   THIS HAS CONTRIBUTED TO MODERATE INSTABILITY OVER THE AREA WITH
   MLCAPE VALUES UP TO 2000 J/KG. MEANWHILE..A LARGE MCS OVER WRN TX
   WAS BEGINNING TO INFLUENCE THE MESOSCALE ENVIRONMENT OVER THE AREA
   WITH INCREASING LOW LEVEL WIND FIELDS AS SEEN ON THE DYX AND FWS VWP
   DATA. ALTHOUGH MID LEVEL FLOW WAS MARGINAL /20-30 KTS/ 10-15 KT ELY
   LOW LEVEL FLOW ALONG AND NORTH OF THE PRIMARY OUTFLOW BOUNDARY OVER
   NORTH TX WILL SUPPORT SUFFICIENT VERTICAL SHEAR FOR SUPERCELLS.
   GIVEN THE MCS GENERATED INCREASING LOW LEVEL FLOW...MODERATE
   VERTICAL SHEAR /0-1 KM SRH AROUND 100 M2/S2/ WILL SUPPORT THE THREAT
   FOR ISOLATED TORNADOES WITH ANY SUPERCELLS THAT MIGHT DEVELOP LATER
   THIS AFTERNOON /SPCLY ALONG THE PRIMARY OUTFLOW BOUNDARY ROUGHLY
   ALONG/NORTH OF I-20/. AS THE AIRMASS CONTINUES TO DESTABILIZE NORTH
   OF THE OUTFLOW BOUNDARY ACROSS NRN TX...SUFFICIENT EFFECTIVE
   VERTICAL SHEAR WILL EXIST TO SUPPORT A MARGINAL SVR THREAT INTO
   PORTIONS OF SCENTRAL/SERN OK.
   
   ..CROSBIE.. 05/08/2007
   
   
   ATTN...WFO...TSA...FWD...OUN...SJT...
   
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