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834 

WWUS20 KWNS 211528

SEL7

SPC WW 211528

CTZ000-MAZ000-MEZ000-NHZ000-NYZ000-PAZ000-VTZ000-LEZ000-LOZ000-CWZ00

0-220000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 507

NWS STORM PREDICTION CENTER NORMAN OK

1130 AM EDT WED JUL 21 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN CONNECTICUT

       WESTERN MASSACHUSETTS

       WESTERN MAINE

       NEW HAMPSHIRE

       NEW YORK

       NORTHERN PENNSYLVANIA

       VERMONT

       LAKE ERIE

       LAKE ONTARIO

       COASTAL WATERS



EFFECTIVE THIS WEDNESDAY MORNING AND EVENING FROM 1130 AM UNTIL

800 PM EDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTH

NORTHWEST OF BRADFORD PENNSYLVANIA TO 45 MILES NORTH NORTHEAST OF

AUGUSTA MAINE.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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.



DISCUSSION...WIDESPREAD STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED

THIS AFTERNOON ACROSS MUCH OF THE NORTHEAST UNITED STATES...AHEAD OF

APPROACHING UPPER TROUGH.  COOL TEMPERATURES ALOFT...INCREASINGLY

STRONG WESTERLY FLOW ALOFT...STEEP LAPSE RATES...AND MODERATE

INSTABILITY WILL CONTRIBUTE TO THE RISK OF LARGE HAIL AND DAMAGING

WINDS.  MULTIPLE BANDS OF STORMS WILL LIKELY AFFECT THE WATCH AREA

THROUGH THE DAY.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 28035.





...HART

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