MESOSCALE DISCUSSION 0539
   NWS STORM PREDICTION CENTER NORMAN OK
   0608 AM CDT SAT MAY 01 2004
   
   AREAS AFFECTED...SERN TX
   
   CONCERNING...TORNADO WATCH 141...
   
   VALID 011108Z - 011245Z
   
   THREAT FOR ISOLATED TORNADOES CONTINUES.  
   
   SURFACE ANALYSIS SHOWS OLD OUTFLOW BOUNDARY LOCATED NEAR
   HOUSTON...WITH COOLER AND MORE STABLE SURFACE AIR TO THE EAST AND A
   MORE UNSTABLE AIR MASS TO THE W.  MODIFIED RUC FORECAST SOUNDINGS
   USING 73-74 F DEWPOINTS YIELD LITTLE IF ANY SURFACE BASED
   INHIBITION. HGX VWP CONTINUES TO SHOW STRONG SHEAR IN THE LOWEST 1
   KM.  USING CURRENT STORM MOTION OF 218/22 PRODUCES 0-1 KM SRH NEAR
   300 M2/S2.  
   
   GREATEST THREAT FOR TORNADOES WILL BE WITH SUPERCELLS THAT ARE ABLE
   TO REMAIN ON WARM SIDE OF BOUNDARY BEFORE MOVING NEWD OVER A MORE
   STABLE AIR MASS...BEFORE COLD FRONT MOVES INTO THE AREA FROM THE NW.
    LATEST VWPS ALSO INDICATE VEERING OF LOW LEVEL JET...WHICH WILL
   DECREASE SHEAR OVER THE NEXT FEW HOURS.
   
   ..JEWELL.. 05/01/2004
   
   
   ATTN...WFO...LCH...SHV...HGX...FWD...CRP...EWX...
   
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