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WWUS20 KWNS 052204

SEL0

SPC WW 052204

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 250

NWS STORM PREDICTION CENTER NORMAN OK

505 PM CDT SAT MAY 5 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL TEXAS



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 505 PM UNTIL

1000 PM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST

SOUTHEAST OF JUNCTION TEXAS TO 25 MILES NORTHEAST OF BROWNWOOD

TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 248...WW 249...



DISCUSSION...A CLUSTER OF THUNDERSTORMS IS EXPECTED TO DEVELOP NEAR

AND JUST E OF A DIFFUSE DRYLINE IN CENTRAL TX.  FLOW ALOFT IS

RELATIVELY WEAK/ANTICYCLONIC...BUT SURFACE TEMPERATURES NEAR 100 F

AND DEWPOINTS IN THE MID 60S ARE CONTRIBUTING TO STEEP LOW-LEVEL

LAPSE RATES AND MLCAPE NEAR 4000 J/KG.  THE WEAK VERTICAL SHEAR

SUGGESTS THAT INDIVIDUAL STORMS WILL NOT BE LONG-LIVED...BUT THE

STEEP LAPSE RATES/LARGE CAPE WILL SUPPORT A RISK OF BOTH STRONG

UPDRAFTS WITH LARGE HAIL...AND STRONG DOWNDRAFTS WITH DAMAGING WIND

POTENTIAL THROUGH LATE EVENING.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 29015.





...THOMPSON

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