MESOSCALE DISCUSSION 0649
   NWS STORM PREDICTION CENTER NORMAN OK
   0308 PM CDT WED MAY 02 2007
   
   AREAS AFFECTED...PARTS OF TX TO THE SOUTH/EAST OF THE BIG BEND
   
   CONCERNING...TORNADO WATCH 209...
   
   VALID 022008Z - 022145Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 209 CONTINUES.
   
   IMPULSE PIVOTING AROUND THE SOUTHERN PERIPHERY OF CLOSED MID-LEVEL
   CIRCULATION OVER THE SOUTHERN ROCKIES HAS TAKEN ON AN INCREASINGLY
   NEGATIVE TILT.  AND...STRONGER MID/UPPER FORCING FOR UPWARD VERTICAL
   MOTION NOW APPEARS TO BE RAPIDLY SHIFTING TOWARD THE TEXAS BIG BEND
   REGION.  NEW CONVECTION IS RAPIDLY DEVELOPING/INTENSIFYING ACROSS
   THE HIGHER TERRAIN TO THE WEST OF THE RIO GRANDE RIVER... WHERE
   LAPSE RATES ARE VERY STEEP AND SUPPORTIVE OF MIXED LAYER CAPE IN
   EXCESS OF 2000 J/KG.  MIXED LAYER CAPE INCREASES TO AROUND 4000 J/KG
   SOUTHWARD THROUGH THE LOWER RIO GRANDE VALLEY...WHERE DEW POINTS ARE
   AROUND 70F...BUT SIGNIFICANT INHIBITION REMAINS.
   
   WITH SHEAR PROFILES STRENGTHENING AS 40+ KT 500 MB JET NOSES JUST TO
   THE SOUTH OF THE TEXAS BIG BEND...SUPERCELLS ARE BECOMING
   INCREASINGLY LIKELY.  INCREASING 2 HOUR SURFACE PRESSURE FALLS ARE
   BECOMING EVIDENT ALONG LINGERING SURFACE BOUNDARY ACROSS THE TEXAS
   HILL COUNTRY INTO THE DEL RIO AREA.  AND...ENLARGED LOW-LEVEL
   HODOGRAPHS NEAR THIS BOUNDARY WILL LIKELY ENHANCE RISK FOR TORNADOES
   AS STORMS GRADUALLY DEVELOP SOUTHEASTWARD OFF THE HIGHER TERRAIN
   BETWEEN NOW AND 03/00Z.
   
   ..KERR.. 05/02/2007
   
   
   ATTN...WFO...CRP...EWX...MAF...
   
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