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000 

WWUS20 KWNS 142028

SEL9

SPC WW 142028

DCZ000-MDZ000-PAZ000-VAZ000-WVZ000-CWZ000-150200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 829

NWS STORM PREDICTION CENTER NORMAN OK

430 PM EDT THU AUG 14 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       WESTERN AND CENTRAL MARYLAND

       SOUTHERN PENNSYLVANIA

       NORTHERN VIRGINIA

       WEST VIRGINIA PANHANDLE

       COASTAL WATERS



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 430 PM UNTIL

1000 PM EDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 60

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 70 MILES WEST OF

MARTINSBURG WEST VIRGINIA TO 50 MILES EAST NORTHEAST OF BALTIMORE

MARYLAND.  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.



OTHER WATCH INFORMATION...CONTINUE...WW 828...



DISCUSSION...CLUSTERS OF STRONG TO SEVERE THUNDERSTORMS WILL REMAIN

POSSIBLE THROUGH THE LATE AFTERNOON AND EVENING HOURS ACROSS PARTS

OF SOUTHERN PA AND THE DELMARVA REGION...WHERE POCKET OF MODERATE

INSTABILITY PERSISTS.  HAIL WILL BE THE MAIN THREAT WITH STRONGER

CELLS.  ACTIVITY SHOULD SLOWLY DIMINISH THROUGH THE PERIOD AS

AIRMASS IS STABILIZED BY ONGOING STORMS...AND DUE TO DIURNAL COOLING

AFTER SUNSET.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 50

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400. MEAN STORM

MOTION VECTOR 27025.





...HART

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