

498 

WWUS20 KWNS 100243

SEL1

SPC WW 100243

NYZ000-PAZ000-100700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 691

NWS STORM PREDICTION CENTER NORMAN OK

1045 PM EDT SUN AUG 9 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SMALL PART OF SOUTHERN NEW YORK

       NORTHERN INTO CENTRAL PENNSYLVANIA



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 1045 PM UNTIL

300 AM EDT.



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 45

STATUTE MILES EITHER SIDE OF A LINE FROM 10 MILES NORTH NORTHWEST

OF DUBOIS PENNSYLVANIA TO 35 MILES EAST OF BINGHAMTON NEW YORK.

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 686...WW 689...WW 690...



DISCUSSION...WATCH IS ESSENTIALLY AN EXTENSION OF WW 690 WITH

STRENGTHENING MCS OVER WRN NY LIKELY SAGGING SSEWD INTO N-CENTRAL

PA/CENTRAL NY LATE THIS EVENING ALONG PERIPHERY OF MODERATE

INSTABILITY.  WEAKENING INSTABILITY OVER ERN NY AND DEEPER INTO PA

SHOULD DIMINISH SEVERE THREAT WITH TIME...ALTHOUGH UNTIL THEN

DAMAGING WINDS REMAIN LIKELY WITH THE STRONGER STORMS.



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 400. MEAN STORM

MOTION VECTOR 34035.





...EVANS

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