

339 

WWUS20 KWNS 241854

SEL7

SPC WW 241854

ARZ000-LAZ000-OKZ000-TXZ000-250300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 707

NWS STORM PREDICTION CENTER NORMAN OK

155 PM CDT SUN OCT 24 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHERN AND CENTRAL ARKANSAS

       NORTHERN LOUISIANA

       FAR SOUTHEAST OKLAHOMA

       NORTHEAST TEXAS



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 155 PM UNTIL

1000 PM CDT.



TORNADOES...HAIL TO 2.5 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 105 STATUTE

MILES EAST AND WEST OF A LINE FROM 55 MILES WEST NORTHWEST OF

PINE BLUFF ARKANSAS TO 65 MILES SOUTH OF LONGVIEW TEXAS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU7).



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...MULTIPLE ZONES OF TSTM GENESIS ARE ANTICIPATED THIS

AFTERNOON...1) ALONG PRE-FRONTAL TROUGH OVER ERN TX...AND 2) WITHIN

FREE-WARM SECTOR ALONG ENHANCED BANDS OF LOW-LEVEL CONFLUENCE.  THE

AMBIENT THERMODYNAMIC ENVIRONMENT IS CHARACTERIZED BY A MOIST

BOUNDARY LAYER WITH DEW POINTS IN THE 60S TO AROUND 70 F.  WHEN

COUPLED WITH STRONG DIABATIC HEATING AND STEEPENING MIDLEVEL LAPSE

RATES FROM THE W...ENVIRONMENT IS ALREADY MODERATELY UNSTABLE WITH

MLCAPE VALUES OF 1500-2500 J/KG.  GIVEN THE PRESENCE OF 40-50 KT

EFFECTIVE BULK SHEAR AND STEADILY STRENGTHENING LOW-LEVEL SHEAR

/I.E. MASS RESPONSE TO APPROACHING VORTICITY MAXIMUM/...SETUP WILL

FAVOR SUPERCELLS CAPABLE OF LARGE HAIL...DAMAGING WINDS AND THE

POSSIBILITY OF A FEW TORNADOES.



AVIATION...TORNADOES AND 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 25030.





...MEAD

