MESOSCALE DISCUSSION 0192
   NWS STORM PREDICTION CENTER NORMAN OK
   0530 PM CST TUE MAR 16 2004
   
   AREAS AFFECTED...PORTIONS W-CENTRAL TX
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 162330Z - 170130Z
   
   ISOLATED CLUSTER OF TSTMS MAY DEVELOP WITHIN AREA OF PERSISTENT LOW
   LEVEL CONVERGENCE OVER W-CENTRAL TX...INVOF ABI...AND MOVE SEWD
   TOWARD BWD/SAN SABA/LLANO REGION.  ANY SUSTAINED/DISCRETE 
   CONVECTION OVER THIS AREA MAY EXHIBIT MIDLEVEL ROTATION WITH
   POTENTIAL FOR HAIL AND STRONG TO MARGINAL SEVERE GUSTS.  WW NOT
   PLANNED ATTM BUT WILL CONTINUE TO MONITOR.
   
   SFC MESOANALYSIS SHOWS DRYLINE AND TWO WEAK BAROCLINIC/CONFLUENCE
   BOUNDARIES THAT INTERSECT IN THIS AREA...ONE EXTENDING ESEWD NEAR
   BWD-ACT-LFK LINE...THE OTHER SSEWD TO NEAR JCT AND SAT.  LATTER
   BOUNDARY ALSO INTERSECTS A WEAK E-W ORIENTED TROUGH AND WIND SHIFT
   LINE INVOF JCT...WHERE LOW CLOUD DEPTH HAS BECOME ENHANCED DURING
   PAST HOUR.
   
   VIS IMAGERY SHOWS RELATIVELY DENSE CONCENTRATION OF TCU AND LARGE CU
   AROUND ABI.  THIS IS CONSISTENT WITH PRESENCE OF AFOREMENTIONED SFC
   BOUNDARY INTERSECTION...MERIDIONAL PRESSURE FALL AXIS...AND
   MESO-BETA SCALE CONVERGENCE MAX INDICATED FOR PAST 2-3 HOURS OVER
   THIS REGION.  ALTHOUGH LOW LEVEL WIND SPEEDS WILL REMAIN
   WEAK...CONSIDERABLE VEERING WITH HEIGHT AND POTENTIAL FOR STRONG
   RIGHTWARD DEVIANCE IN STORM MOTIONS SUPPORT RISK OF A SUPERCELL OR
   TWO.  ACCORDINGLY MODIFIED DYS VWP AND RUC HODOGRAPHS INDICATE
   AROUND 150 J/KG 0-3 KM SRH POSSIBLE.  SFC-6 KM SHEAR IS EVEN MORE
   FAVORABLE AT 60-75 KT...BECAUSE OF STRONG VEERING WITH HEIGHT
   BENEATH 55-60 KT 6 KM AGL FLOW.  ACTIVITY WOULD MOVE PREFERENTIALLY
   SEWD TO SSEWD INTO MORE FAVORABLE INSTABILITY. MODIFIED RUC
   SOUNDINGS INDICATE LITTLE OR NO CAP...WITH MLCAPE 500-800 J/KG OVER
   SAN SABA/LLANO AREAS.  MLCAPE IS GRADUALLY INCREASING WITH SWD
   EXTENT TO AROUND 1200 J/KG IN JCT/DRT AREA WHERE LOW LEVEL FORCING
   IS WEAKER AND CAPPING STRONGER.  TIME WINDOW FOR SFC-BASED
   DEVELOPMENT IS GETTING NARROW...HOWEVER.  BEST POTENTIAL WILL
   DIMINISH AFTER 01Z AS LOSS OF DIABATIC SFC HEATING REDUCES CAPE.
   
   ..EDWARDS.. 03/16/2004
   
   
   ATTN...WFO...FWD...EWX...SJT...
   
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