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022 

WWUS20 KWNS 091600

SEL3

SPC WW 091600

NYZ000-PAZ000-LEZ000-LOZ000-092300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 683

NWS STORM PREDICTION CENTER NORMAN OK

1200 PM EDT SUN AUG 9 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN AND CENTRAL NEW YORK

       NORTHERN PENNSYLVANIA

       LAKE ERIE

       LAKE ONTARIO



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM NOON UNTIL 700

PM EDT.



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 65

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

SOUTHWEST OF JAMESTOWN NEW YORK TO 25 MILES SOUTH SOUTHEAST OF

UTICA NEW YORK.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 680...WW 681...WW 682...



DISCUSSION...LINE OF STRONG/SEVERE STORMS ACROSS SRN ONTARIO IS

EXPECTED TO CROSS PARTS OF LAKE ONTARIO AND ERN LAKE ERIE AND MOVE

INTO PARTS OF NY AND PA THIS AFTERNOON.  STORMS ARE ASSOCIATED WITH

UPPER SHORT WAVE TROUGH MOVING EWD ACROSS THE NRN LAKES.  CLOUDS ARE

THINNING OVER WRN NY ATTM...AND HEATING/DESTABILIZATION ARE EXPECTED

TO INCREASE WITH MLCAPE REACHING 1000-1500 J/KG.  30-40 WNWLY MID

LEVEL WINDS ARE CONTRIBUTING TO SUFFICIENT DEEP LAYER SHEAR TO

MAINTAIN ORGANIZED QLCS...WITH POTENTIAL FOR STRONGER STORMS TO

PRODUCE DAMAGING WIND GUSTS 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 500. MEAN STORM

MOTION VECTOR 28025.





...WEISS

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