

158 

WWUS20 KWNS 162013

SEL8

SPC WW 162013

TXZ000-170200-



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

