

475 

WWUS20 KWNS 161151

SEL2

SPC WW 161151

LAZ000-TXZ000-CWZ000-161900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 682

NWS STORM PREDICTION CENTER NORMAN OK

550 AM CST SUN DEC 16 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN...CENTRAL AND NORTHERN LOUISIANA

       SOUTHEAST AND EAST TEXAS

       COASTAL WATERS



EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 550 AM UNTIL 100

PM CST.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 80 MILES SOUTHWEST

OF COLLEGE STATION TEXAS TO 40 MILES NORTH NORTHEAST OF NATCHEZ

MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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...TSTMS FCST TO CONTINUE INCREASING IN COVERAGE AND

SPREAD FROM W-E ACROSS WW AREA...WHILE STRENGTHENING TO SVR LEVELS.

STG MID-UPPER WINDS -- E.G. 90 KT OBSERVED AROUND 6 KM AGL OVER LDB

PROFILER SITE -- WILL CONTRIBUTE TO FAVORABLE DEEP-LAYER SHEAR.

MEAN-WIND AND DEEP-SHEAR VECTORS WILL BE ALIGNED NEARLY PARALLEL TO

LOW-LEVEL FRONTAL/CONVERGENCE ZONE...SUPPORTING PREDOMINANT

QUASI-LINEAR AND CLUSTERED MODES...WITH LEWPS AND SMALL BOWS

POSSIBLE.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 24035.





...EDWARDS

