

466 

WWUS20 KWNS 131804

SEL1

SPC WW 131804

OKZ000-TXZ000-140200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 661

NWS STORM PREDICTION CENTER NORMAN OK

100 PM CDT SAT OCT 13 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WESTERN AND CENTRAL OKLAHOMA

       NORTHWEST TEXAS



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 100 PM UNTIL

900 PM CDT.



TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE

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

ALVA OKLAHOMA TO 20 MILES SOUTH SOUTHWEST OF ABILENE TEXAS.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU1).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



DISCUSSION...THUNDERSTORM DEVELOPMENT IS LIKELY IN THE NEXT COUPLE

OF HOURS FROM NW TX INTO WRN OK...ALONG AND JUST E OF THE SURFACE

COLD FRONT.  A NARROW ZONE OF SURFACE HEATING  TO THE W OF THE

ONGOING CONVECTION FROM N TX INTO CENTRAL OK...AND BOUNDARY LAYER

DEWPOINTS IN THE UPPER 60S...ARE SUPPORTING MLCAPE NEAR 2000 J/KG.

DEEP-LAYER AND LOW-LEVEL VERTICAL SHEAR ARE FAVORABLE FOR

SUPERCELLS...AND THE CONVECTIVE MODE SHOULD BE A MIX OF

SEMI-DISCRETE CELLS AND LINE SEGMENTS THROUGH THE AFTERNOON.  A FEW

TORNADOES WILL BE POSSIBLE WITH THE MORE DISCRETE STORMS THROUGH THE

AFTERNOON/EVENING...ALONG WITH LARGE HAIL.  DAMAGING WINDS WILL

BECOME MORE OF A THREAT LATER AS STORMS POTENTIALLY EVOLVE INTO A

MORE SOLID LINE CLOSER TO I-35 IN OK.



AVIATION...TORNADOES AND 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

500. MEAN STORM MOTION VECTOR 24035.





...THOMPSON

