

745 

WWUS20 KWNS 202157

SEL2

SPC WW 202157

ARZ000-OKZ000-TXZ000-210400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 2

NWS STORM PREDICTION CENTER NORMAN OK

355 PM CST WED JAN 20 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME SOUTHWEST ARKANSAS

       SOUTH CENTRAL AND SOUTHEAST OKLAHOMA

       NORTH CENTRAL AND NORTHEAST TEXAS



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 355 PM UNTIL

1000 PM CST.



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 80 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 40 MILES WEST NORTHWEST OF

FORT WORTH TEXAS TO 10 MILES SOUTH OF TEXARKANA ARKANSAS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU2).



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.



OTHER WATCH INFORMATION...CONTINUE...WW 1...



DISCUSSION...THUNDERSTORMS ARE EXPECTED TO DEVELOP AND INTENSIFY

ACROSS PART OF NORTH CENTRAL TX/SOUTH CENTRAL OK ALONG WARM FRONT IN

RESPONSE TO INCREASING DYNAMIC FORCING FOR ASCENT ASSOCIATED WITH

STRONG UPPER TROUGH APPROACHING FROM THE WEST.  RELATIVELY STEEP

LAPSE RATES ABOVE MOIST PBL ARE CONTRIBUTING TO UNSTABLE ENVIRONMENT

WITH MLCAPE OF 1000-1500 J/KG. EFFECTIVE BULK SHEAR CURRENTLY IN THE

35-45 KT RANGE IS SUPPORTIVE OF SUPERCELL DEVELOPMENT...AND LOW LCL

HEIGHTS AND SUFFICIENT LOW LEVEL SHEAR/SRH WILL ENHANCE THREAT FOR A

FEW TORNADOES WITH DISCRETE CELLS THAT FORM.



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

450. MEAN STORM MOTION VECTOR 25035.





...WEISS

