WATCHES: Severe Thunderstorm Watch Number 156

WWUS20 KWNS 192245
SEL6
SPC WW 192245
TXZ000-200400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 156
NWS STORM PREDICTION CENTER NORMAN OK
545 PM CDT TUE APR 19 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND NORTH CENTRAL TEXAS

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 545 PM UNTIL
1100 PM CDT.

HAIL TO 3 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 70
STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH
NORTHEAST OF CORSICANA TEXAS TO 65 MILES SOUTHWEST OF TEMPLE
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

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 154...WW 155...

DISCUSSION...THUNDERSTORMS WILL CONTINUE TO DEVELOP SWD ALONG THE
DRYLINE-COLD FRONT INTERSECTION...WITH THE STORMS FED BY STRONG
INSTABILITY AND STEEP MIDLEVEL LAPSE RATES. THE COMBINATION OF
MLCAPE VALUES IN EXCESS OF 4000 J/KG AND EFFECTIVE BULK SHEAR NEAR
40 KT WILL SUPPORT SUPERCELLS CAPABLE OF PRODUCING ISOLATED VERY
LARGE HAIL...ALONG WITH DAMAGING WINDS. FARTHER S...MORE ISOLATED
STORM DEVELOPMENT WILL BE POSSIBLE ALONG THE STALLED DRYLINE IN THE
HILL COUNTRY...WHERE STRONG SURFACE HEATING HAS WEAKENED THE
CAP...BUT FORCING FOR ASCENT IS WEAK.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM
MOTION VECTOR 32020.

...THOMPSON

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