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957 

WWUS20 KWNS 231446

SEL8

SPC WW 231446

DCZ000-MDZ000-PAZ000-VAZ000-WVZ000-CWZ000-232200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 338

NWS STORM PREDICTION CENTER NORMAN OK

1050 AM EDT MON MAY 23 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       MARYLAND

       CENTRAL PENNSYLVANIA

       NORTHERN VIRGINIA

       EASTERN WEST VIRGINIA PANHANDLE

       COASTAL WATERS



EFFECTIVE THIS MONDAY MORNING AND EVENING FROM 1050 AM UNTIL 600

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 EAST AND WEST OF A LINE FROM 50 MILES EAST

NORTHEAST OF STATE COLLEGE PENNSYLVANIA TO 25 MILES EAST OF

CHARLOTTESVILLE VIRGINIA.  FOR A COMPLETE DEPICTION OF THE WATCH

SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 337...



DISCUSSION...TSTMS CURRENTLY DEVELOPING AHEAD OF MCV FROM WRN PA TO

ERN VA SHOULD CONTINUE TO INCREASE IN COVERAGE AND INTENSITY THIS

AFTERNOON AS ACTIVITY ENCOUNTERS A DESTABILIZING AIR MASS E OF THE

BLUE RIDGE.  THE COMBINATION OF MLCAPE INCREASING TO 1000-2000 J/KG

AND STRONG WLY MID-TROPOSPHERIC FLOW /REF. 12Z ILN SOUNDING/ WILL

PROMOTE UPSCALE GROWTH OF STORMS INTO AN MCS CAPABLE OF LARGE HAIL

AND DAMAGING WIND GUSTS.



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 27035.





...MEAD

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