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464 

WWUS20 KWNS 191704

SEL1

SPC WW 191704

CTZ000-DEZ000-MAZ000-NJZ000-NYZ000-PAZ000-CWZ000-200100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 791

NWS STORM PREDICTION CENTER NORMAN OK

105 PM EDT FRI AUG 19 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME WESTERN CONNECTICUT

       EXTREME NORTHERN DELAWARE

       EXTREME WESTERN MASSACHUSETTS

       NEW JERSEY

       SOUTHEAST NEW YORK

       EASTERN PENNSYLVANIA

       COASTAL WATERS



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 105 PM UNTIL 900

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 90

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES WEST

NORTHWEST OF PITTSFIELD MASSACHUSETTS TO 35 MILES SOUTH SOUTHEAST

OF HARRISBURG PENNSYLVANIA.  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.



DISCUSSION...SCATTERED PULSE-TYPE STORMS WILL CONTINUE TO INCREASE

IN COVERAGE/INTENSITY DURING THE NEXT FEW HOURS IN CONJUNCTION WITH

DAYTIME HEATING/DESTABILIZATION...AS WELL AS STORM/OUTFLOW MERGERS.

THOUGH DEEP-LAYER VERTICAL SHEAR WILL REMAIN WEAK ACROSS THE WATCH

AREA...MLCAPE OF 1500-2000 J/KG AND RELATIVELY COOL MIDLEVEL

TEMPERATURES WILL SUPPORT MARGINALLY SEVERE HAIL WITH THE STRONGER

UPDRAFTS.  AS THE STORMS COLLAPSE...ISOLATED DAMAGING DOWNBURSTS

WILL ALSO BE POSSIBLE.



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 27015.





...THOMPSON

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