SEVERE THUNDERSTORM WATCH NUMBER 78

SEL8

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 78
NWS STORM PREDICTION CENTER NORMAN OK
315 PM CDT FRI MAR 16 2012

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

SOUTHWEST AND WEST CENTRAL TEXAS

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 315 PM UNTIL 900
PM CDT.

HAIL TO 2.5 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 50 MILES NORTH OF BIG
SPRING TEXAS TO 45 MILES WEST OF DRYDEN TEXAS. FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU8).

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.

DISCUSSION...THUNDERSTORMS ARE BEGINNING TO DEVELOP NEAR THE DAVIS
MOUNTAINS IN SW TX...AND THIS AREA OF CONVECTION IS EXPECTED TO
EXPAND EWD/NEWD THROUGH THE AFTERNOON IN RESPONSE TO CONTINUED
DAYTIME HEATING AND THE APPROACH OF A WEAK MIDLEVEL TROUGH FROM FAR
W TX/SRN NM. THE COMBINATION OF MLCAPE AOA 2000 J/KG...EFFECTIVE
BULK SHEAR AOA 40 KT...AND STRAIGHT HODOGRAPHS WILL SUPPORT
SPLITTING SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL AND ISOLATED
DAMAGING WINDS. THE ERN EXTENT OF THE SEVERE THREAT WILL BE LIMITED
BY THE PERSISTENT STRATUS AND WEAKER INSTABILITY...WHILE THE TORNADO
RISK APPEARS LIMITED BY RELATIVELY WEAK LOW-LEVEL SHEAR.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27020.


...THOMPSON