

070 

WWUS20 KWNS 111759

SEL7

SPC WW 111759

DCZ000-MDZ000-VAZ000-WVZ000-CWZ000-120000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 377

NWS STORM PREDICTION CENTER NORMAN OK

200 PM EDT THU JUN 11 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       MUCH OF CENTRAL MARYLAND

       CENTRAL VIRGINIA

       THE EXTREME ERN WEST VIRGINIA PANHANDLE

       COASTAL WATERS



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 200 PM UNTIL

800 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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST

NORTHEAST OF MARTINSBURG WEST VIRGINIA TO 10 MILES SOUTH

SOUTHWEST OF SOUTH HILL VIRGINIA.  FOR A COMPLETE DEPICTION OF

THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS

WOU7).



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 374...WW 375...WW 376...



DISCUSSION...THE REMNANT OUTFLOW WITH AN OVERNIGHT AND MORNING MCS

IS PROGRESSING EWD INTO WRN/CENTRAL VA AND MD ALONG WITH A BELT OF

40-50 KT MID LEVEL FLOW ACCOMPANYING AN ASSOCIATED MCV.  GIVEN

SURFACE HEATING/DESTABILIZATION E OF THIS SYSTEM...ESPECIALLY ACROSS

CENTRAL/SRN VA...EXPECT CONVECTION TO INCREASE ALONG THE OUTFLOW

BOUNDARY WITH AN INCREASING THREAT FOR DAMAGING WINDS AND LARGE HAIL

THROUGH THE AFTERNOON.



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 27025.





...THOMPSON

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