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340 

WWUS20 KWNS 200038

SEL8

SPC WW 200038

TNZ000-200800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 498

NWS STORM PREDICTION CENTER NORMAN OK

735 PM CDT THU JUL 19 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN AND MIDDLE TENNESSEE



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 735 PM

UNTIL 300 AM CDT.



HAIL TO 1.5 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 120

STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH

NORTHWEST OF CROSSVILLE TENNESSEE TO 45 MILES EAST SOUTHEAST OF

NASHVILLE TENNESSEE.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 495...WW 496...WW 497...



DISCUSSION...SEVERE STORM ACTIVITY ACROSS SRN AND CNTRL KY WILL

CONTINUE TO DRIFT SOUTH OVER THE NEXT FEW HOURS INTO A VERY UNSTABLE

AIRMASS ALONG THE TN/KY BORDER. RECENT BNA SOUNDING DEPICTS ABUNDANT

INSTABILITY WITH MLCAPE IN EXCESS OF 3000 J/KG...A WARM ADVECTION

WIND PROFILE AND A WEAK NNWLY MEAN WIND THAT SHOULD STEER CONVECTION

SOUTH ACROSS THE KY/TN BORDER BETWEEN 01 AND 03Z. PRIMARY THREAT

SHOULD CONTINUE TO BE DAMAGING WINDS FROM A MARGINALLY ORGANIZED

QLCS INTO LATER THIS EVENING. WEAK DEEP-LAYER FLOW AND FORCING...AND

STRONG DIABATIC INFLUENCE ON THE ONGOING CONVECTION WOULD SUGGEST

THAT THE OVERALL SEVERE WEATHER THREAT SHOULD WANE AS BOUNDARY LAYER

BEGINS TO STABILIZE LATER TONIGHT.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM

MOTION VECTOR 33020.





...CARBIN

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