MESOSCALE DISCUSSION 2048
   NWS STORM PREDICTION CENTER NORMAN OK
   0242 PM CDT THU AUG 19 2004
   
   AREAS AFFECTED...CENTRAL TX
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL...HEAVY RAINFALL 
   
   VALID 191942Z - 192215Z
   
   TSTMS MAY BECOME SEVERE THROUGH AT LEAST 23Z OVER NRN HILL COUNTRY 
   AND EWD ACROSS ACT AREA.  ISOLATED STRONG-SEVERE GUSTS AND HAIL ARE
   POSSIBLE.  MARGINAL TORNADO POTENTIAL ALSO EVIDENT GIVEN POSSIBILITY
   OF LOCALIZED BOUNDARY/STORM-SCALE INTERACTIONS.
   
   RESIDUAL MCS CONTINUES TO MOVE EWD ACROSS EXTREME NERN TX AND NERN
   TX /SWRN AR.  SFC MESOANALYSIS SHOWS OUTFLOW BOUNDARY PRODUCED BY
   THAT COMPLEX EXTENDING SWWD TO AROUND 20 SE CRS...THEN WWD ACROSS
   NRN MCLENNAN COUNTY TO COKE COUNTY.  AIR MASS N OF THIS BOUNDARY
   WILL REMAIN RELATIVELY STABLE FOR SEVERAL HOURS OVER NERN TX BECAUSE
   OF RELATIVELY DEEP/FRESH COLD POOL GENERATION BY MCS...HOWEVER
   INSOLATION WILL DESTABILIZE AIR MASS ON BOTH SIDES OF BOUNDARY W OF
   I-45 AND AWAY FROM CONVECTION. BOUNDARY HAS DRIFTED N PAST ACT AND
   SHOULD SHIFT TO NEAR A CRS...BWD...20 N SJT LINE BY 21Z. 
   SEPARATE/WEAKER OUTFLOW BOUNDARY -- GENERATED BY INCREASING
   CONVECTION OVER SE TX -- SHOULD EXTEND FROM AROUND FREESTONE COUNTY
   SSEWD ALONG I-45...INTERSECTING FIRST BOUNDARY SSE OF CRS AND
   PROVIDING EFFECTIVE ERN BOUND FOR SEVERE POTENTIAL.
   
   PRESSURE FALLS REMAIN MAXIMIZED INVOF ACT AND ASSOCIATED
   BACKING/STRENGTHENING OF FLOW SHOULD HELP TO MAINTAIN FAVORABLE
   BOUNDARY LAYER HODOGRAPHS.  VWP AND RUC FCST SOUNDINGS SUGGEST 0-3
   KM SRH WILL REACH 150-300 J/KG AND 0-1 KM SRH UP TO NEAR 100-250
   J/KG DURING REMAINDER AFTERNOON -- MAXIMIZED IN BWD-ACT CORRIDOR.
   THIS ALSO WILL CORRESPOND TO NRN EDGE OF MOST FAVORABLE BUOYANCY. 
   NARROW ZONE IS EVIDENT ALONG AND JUST N OF OUTFLOW BOUNDARY WITH 0-6
   KM AGL SHEARS 30-35 KT...35-45 J/KG BRN SHEAR...MLCAPE AROUND 1500
   J/KG...AND CINH AOB 25 J/KG.  GIVEN VERY RICH LOW-MIDLEVEL MOISTURE
   OVER REGION...EFFICIENT PRECIP PRODUCTION IS EXPECTED AS
   WELL....WITH RAIN RATES 2-3 INCHES/HOUR IN MOST INTENSE CORES.
   
   ..EDWARDS.. 08/19/2004
   
   
   ATTN...WFO...FWD...SJT...
   
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