

063 

WWUS20 KWNS 192130

SEL4

SPC WW 192130

ALZ000-TNZ000-200300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 174

NWS STORM PREDICTION CENTER NORMAN OK

430 PM CDT SUN APR 19 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF NORTHERN ALABAMA

       SOUTHERN PORTION OF MIDDLE TENNESSEE



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 430 PM UNTIL

1000 PM 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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES NORTHWEST

OF MUSCLE SHOALS ALABAMA TO 70 MILES EAST NORTHEAST OF HUNTSVILLE

ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 171...WW 172...WW 173...



DISCUSSION...STRONG/SEVERE THUNDERSTORMS HAVE DEVELOPED NRN MS AHEAD

OF UPPER TROUGH.  WITH 50KT OF DEEP LAYER SHEAR AND 7C/KM LAPSE

RATES...SUFFICIENT INSTABILITY TO SUPPORT SEVERE THUNDERSTORMS

CONTINUING E/NE ACROSS THE WATCH AREA THIS EVENING. PRIMARY THREAT

WILL BE LOCAL DAMAGING WINDS AND LARGE HAIL.



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 450. MEAN STORM

MOTION VECTOR 24035.





...HALES

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