MESOSCALE DISCUSSION 0569
   NWS STORM PREDICTION CENTER NORMAN OK
   0644 PM CDT TUE APR 24 2007
   
   AREAS AFFECTED...PORTIONS CENTRAL/SW TX...ADJACENT RIO GRANDE
   VALLEY.
   
   CONCERNING...TORNADO WATCH 179...
   
   VALID 242344Z - 250145Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 179 CONTINUES.
   
   SFC MESOANALYSIS SHOWS DRYLINE NEAR LINE FROM 10 W FSI...30 E
   DYS...25 E SJT...50 NW DRT.  LOCALIZED/ERRATIC DRYLINE MOTION IS
   POSSIBLE BUT LITTLE OVERALL MOVEMENT IS EXPECTED NEXT 2-3 HOURS. 
   BKN BAND OF STG-SVR TSTMS -- INCLUDING A COUPLE EMBEDDED SUPERCELLS
   -- IS EVIDENT ATTM FROM BWD AREA SWWD TO NRN VAL VERDE COUNTY. 
   ADDITIONAL ACTIVITY MAY BACKBUILD ALONG DRYLINE THROUGH REMAINDER
   VAL VERDE COUNTY INTO ADJACENT PORTIONS NRN COAHUILA...AND MOVE EWD
   ACROSS ERN PORTION WW.  TORNADOES...LARGE HAIL AND DAMAGING GUSTS
   ALL ARE POSSIBLE GIVEN WARM SECTOR ENVIRONMENT CHARACTERIZED BY
   2000-3000 J/KG MLCAPES...45-60 KT EFFECTIVE BULK SHEAR...AND 0-1 KM
   SRH AROUND 300 J/KG.
   
   ADDITIONAL/SMALL WW MAY BE REQUIRED S OF 179 INVOF RIO GRANDE
   VALLEY.  VERY INTENSE/HEAVY-PRECIP SUPERCELL WITH CYCLIC
   MESOCYCLONES MAY BE PRODUCING TORNADOES AND VERY LARGE/DAMAGING HAIL
   JUST W OF RIVER IN MEX AND WILL MOVE OVER EAGLE PASS VERY SHORTLY. 
   PROJECTED DEVIANT/RIGHTWARD MOTION TAKES THIS STORM S AND SE OF
   EAGLE PASS REGION...ACROSS SRN PORTIONS MAVERICK COUNTY TOWARD WRN
   DIMMIT AND NWRN WEBB COUNTY.  HOWEVER...MODIFIED RUC SOUNDINGS
   INDICATE CONSIDERABLE INCREASE IN CINH WITH SEWD EXTENT DOWN
   VALLEY...CASTING CONSIDERABLE DOUBT UPON LONGEVITY OF THIS ACTIVITY
   PAST ROUGHLY DIMMIT/WEBB COUNTY LINE.
   
   ..EDWARDS.. 04/24/2007
   
   
   ATTN...WFO...HGX...FWD...CRP...EWX...SJT...
   
   29770163 30540089 31829933 32009849 31869569 31119579
   30069767 29599830 29479809 29089839 29259877 28609877
   28149929 27839964 27909998