

963 

WWUS20 KWNS 142036

SEL1

SPC WW 142036

OKZ000-TXZ000-150200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 681

NWS STORM PREDICTION CENTER NORMAN OK

230 PM CST FRI DEC 14 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       FAR WESTERN OKLAHOMA

       THE TEXAS PANHANDLE AND TEXAS SOUTH PLAINS



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 230 PM UNTIL 800

PM CST.



HAIL TO 0.5 INCH 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 90

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 75 MILES WEST OF

PLAINVIEW TEXAS TO 65 MILES NORTHEAST OF CHILDRESS TEXAS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU1).



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...A LINE OF FORCED...LOW-TOPPED STORMS HAS FORMED ALONG

PACIFIC COLD FRONT OVER FAR ERN NM...AHEAD OF POTENT SHORTWAVE

TROUGH ACCELERATING ENE ACROSS THE FOUR CORNERS REGION. CLEARANCE OF

MID/UPR LVL CLOUD COVER HAS ALLOWED LOW-LVL LAPSE RATES TO

SUFFICIENTLY STEEPEN ALONG A WIDE ENOUGH SWATH TO SUGGEST THAT

CONVECTIVE BAND MAY FURTHER INTENSIFY AS IT CONTINUES RAPIDLY ENE

INTO W TX. IN FURTHER SUPPORT OF STORM STRENGTHENING IS THE NEARLY

SIMULTANEOUS ARRIVAL OF STRONGER DCVA/MID LVL COLD ADVECTION

ASSOCIATED WITH LEADING EDGE OF UPR TROUGH.

GIVEN 40-50 KT MEAN LWR TROPOSPHERIC FLOW AHEAD OF FRONT...AND SOME

STRENGTHENING OF MEAN FLOW EXPECTED ACROSS AREA THROUGH EARLY

EVE...SETUP APPEARS TO SUPPORT AN APPRECIABLE ENOUGH RISK FOR SVR

WIND GUSTS TO WARRANT WW ISSUANCE. THE SVR THREAT SHOULD DIMINISH

LATER THIS EVE AS THE CONVECTIVE LINE MOVES BEYOND REGION OF

GREATEST DIURNAL HEATING...ALTHOUGH STORMS MAY REMAIN ACTIVE NEWD

INTO PARTS OF ERN OK/KS LATER TNGT.



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

TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 350. MEAN STORM

MOTION VECTOR 24045.





...CORFIDI

