

059 

WWUS20 KWNS 212319

SEL1

SPC WW 212319

LAZ000-TXZ000-220700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 501

NWS STORM PREDICTION CENTER NORMAN OK

615 PM CDT SAT JUL 21 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN LOUISIANA

       NORTHEAST TEXAS



EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 615 PM

UNTIL 200 AM CDT.



HAIL TO 2 INCHES 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 110

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES SOUTHEAST OF

COLLEGE STATION TEXAS TO 30 MILES NORTH NORTHEAST OF TYLER 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.



OTHER WATCH INFORMATION...CONTINUE...WW 500...



DISCUSSION...ROBUST TSTM DEVELOPMENT WAS OCCURRING ALONG A

RESIDUAL/DECAYING FRONT SITUATED FROM THE DFW AREA WWD TO THE

ARKLATEX THIS EVENING. POOL OF STRONG INSTABILITY EXISTS AHEAD OF

THIS STORM DEVELOPMENT AND DEEP-LAYER MEAN WINDS FROM THE NORTH

SHOULD STEER STORMS SOUTH INTO THE HIGHLY UNSTABLE AIR. DOWNBURST

WINDS APPEAR TO BE THE MOST LIKELY THREAT GIVEN THE HOT CONDITIONS

AND HIGH DCAPE. SOME UPSCALE/MCS ORGANIZATION IS POSSIBLE IF COLD

POOLS CAN MERGE AND DEEPEN WITHIN A BELT OF 15KT MID LEVEL FLOW

ORIENTED FAVORABLY TO THE LINE OF LOW LEVEL CONVERGENCE AND STORM

DEVELOPMENT.

AN OUTFLOW BOUNDARY FROM GULF COAST CONVECTION WAS SITUATED ACROSS

THE SRN PORTIONS OF THE WATCH AREA FROM N OF HOU TO THE SABINE

RIVER. WHILE MORE STABLE POST-MCS AIRMASS EXISTS ACROSS SOME OF THIS

AREA...THE BOUNDARY COULD SERVE AS A FOCUS FOR ADDITIONAL STRONG TO

SEVERE STORM DEVELOPMENT LATER THIS EVENING WHERE CONVERGENCE AND

LIFT WILL BE ENHANCED ON THE EDGE OF THE STRONGER INSTABILITY INLAND

FROM THE GULF COAST.



AVIATION...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 36025.





...CARBIN

