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WWUS20 KWNS 091521

SEL4

SPC WW 091521

NHZ000-NYZ000-VTZ000-092100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 494

NWS STORM PREDICTION CENTER NORMAN OK

1120 AM EDT MON JUL 9 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN AND CENTRAL NEW HAMPSHIRE

       NORTHERN NEW YORK

       NORTHERN AND CENTRAL VERMONT



EFFECTIVE THIS MONDAY MORNING AND AFTERNOON FROM 1120 AM UNTIL

500 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 45

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES WEST

NORTHWEST OF SARANAC LAKE NEW YORK TO 15 MILES EAST OF MOUNT

WASHINGTON NEW HAMPSHIRE.  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.



DISCUSSION...A CLUSTER OF TSTMS CONTINUES TO INTENSIFY THIS MORNING

INVOF OF WARM FRONT...DRIVEN LARGELY BY ENHANCED ZONE OF LOW-LEVEL

WAA ATTENDANT TO LOW-AMPLITUDE...MID-LEVEL SPEED MAXIMUM TRANSLATING

EWD ACROSS SRN QB.  VERTICAL SHEAR PROFILES ARE RELATIVELY STRONG

AND SUPPORTIVE OF SUPERCELLS AND/OR BOWING SEGMENTS CAPABLE OF

DAMAGING WINDS AND LARGE HAIL.  WHILE A BRIEF TORNADO IS

POSSIBLE...STORMS MAY TEND REMAIN SLIGHTLY ELEVATED ABOVE A NEAR

SURFACE INVERSION WHICH SHOULD EFFECTIVELY LIMIT A MORE SUBSTANTIAL

THREAT.



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 28035.





...MEAD/THOMPSON

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