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WWUS20 KWNS 251537

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SPC WW 251537

NYZ000-OHZ000-PAZ000-WVZ000-252300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 683

NWS STORM PREDICTION CENTER NORMAN OK

1140 AM EDT MON JUL 25 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN...SOUTHERN TIER...AND PARTS OF EASTERN NEW YORK

       EASTERN OHIO

       MUCH OF WESTERN AND NORTHERN PENNSYLVANIA

       NORTHERN WEST VIRGINIA PANHANDLE



EFFECTIVE THIS MONDAY MORNING AND EVENING FROM 1140 AM UNTIL 700

PM 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 70

STATUTE MILES NORTH AND SOUTH OF A LINE FROM AKRON OHIO TO 5

MILES NORTH NORTHEAST OF ALBANY 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.



DISCUSSION...VSBL SATL IMAGERY DEPICTS AN AXIS OF RELATIVELY CLEAR

SKIES FROM OH ENEWD ACROSS THE SRN TIER OF NY. EXPECT THAT SURFACE

HEATING ACROSS THIS CORRIDOR...ALONG WITH INCREASINGLY FAVORABLE

LARGE SCALE ASCENT ASSOCIATED WITH AN APPROACHING UPPER

TROUGH...WILL SUPPORT THE CONTINUED DEVELOPMENT OF SEVERE TSTMS INTO

THE AFTERNOON. COINCIDENT WITH THE INCREASE IN INSTABILITY WITHIN

THE VERY MOIST AND WARMING AIRMASS...DEEP LAYER SHEAR WILL BECOME

INCREASINGLY STRONG AS 40-50KT MID-LEVEL SPEED MAX SPREADS EAST FROM

THE UPPER GREAT LAKES. THIS WILL PROMOTE LONGER-LIVED/ORGANIZED

UPDRAFTS LIKELY TAKING THE FORM OF LINE/BOWING SEGMENTS CAPABLE OF

PRODUCING DAMAGING WINDS AS WELL AS SOME HAIL.



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 450. MEAN STORM

MOTION VECTOR 29030.





...CARBIN

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