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628 

WWUS20 KWNS 291843

SEL9

SPC WW 291843

NJZ000-NYZ000-PAZ000-CWZ000-300300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 699

NWS STORM PREDICTION CENTER NORMAN OK

240 PM EDT FRI JUL 29 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN AND CENTRAL NEW JERSEY

       SOUTH-CENTRAL AND SOUTHEAST NEW YORK

       CENTRAL AND EASTERN PENNSYLVANIA

       COASTAL WATERS



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 240 PM UNTIL

1100 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 75

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST OF

STATE COLLEGE PENNSYLVANIA TO 30 MILES NORTH OF NEW YORK CITY NEW

YORK.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY THIS AFTERNOON ALONG THE SRN FRINGE OF STRONGER HEIGHT

FALLS/DYNAMIC FORCING FOR ASCENT ASSOCIATED WITH SHORT WAVE TROUGH

MOVING ACROSS UPSTATE NY.  AREA VAD DATA INDICATE THAT SHORT WAVE

TROUGH IS ASSOCIATED WITH A BELT OF 40-50 KT WLY WINDS IN THE

MIDLEVELS OVER NRN PA/SRN NY WHERE THE POTENTIAL WILL EXIST FOR

SUPERCELLS CAPABLE OF MAINLY DAMAGING WINDS.  WHILE VERTICAL SHEAR

DECREASES WITH SWD EXTENT ACROSS THE WATCH AREA...INSTABILITY

INCREASES WITH THE POTENTIAL FOR DAMAGING WINDS IN CONJUNCTION WITH

DEVELOPING LINE SEGMENTS AND MULTICELL CLUSTERS. A TORNADO WILL ALSO

BE POSSIBLE WITH ANY MATURE SUPERCELLS THAT CAN FAVORABLY INTERACT

WITH WARM FRONT LIFTING NWD THROUGH NERN PA/SERN NY.



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 500. MEAN STORM

MOTION VECTOR 27030.





...MEAD

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