

000 

WWUS20 KWNS 232059

SEL0

SPC WW 232059

DCZ000-MDZ000-VAZ000-WVZ000-CWZ000-240200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 600

NWS STORM PREDICTION CENTER NORMAN OK

500 PM EDT MON JUN 23 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       MARYLAND

       NORTHERN VIRGINIA

       EXTREME EASTERN WEST VIRGINIA PANHANDLE

       COASTAL WATERS



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 500 PM UNTIL

1000 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 35 MILES NORTH OF

BALTIMORE MARYLAND TO 55 MILES SOUTH SOUTHWEST OF WASHINGTON

DISTRICT OF COLUM.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 599...



DISCUSSION...SCATTERED THUNDERSTORMS ARE INTENSIFYING ALONG A

DIFFUSE FRONTAL SEGMENT/SURFACE TROUGH ACROSS NRN VA.  CONVECTIVE

COVERAGE THROUGH THE EVENING WILL BE ENHANCED BY ASCENT IN ADVANCE

OF A MID LEVEL TROUGH APPROACHING FROM THE W.  THOUGH SOME LOW-LEVEL

DRYING HAS OCCURRED DURING THE AFTERNOON...INSTABILITY WILL REMAIN

SUFFICIENT FOR STORMS WITH STRONG UPDRAFTS...WHILE COOL MID LEVEL

TEMPERATURES WILL SUPPORT A THREAT FOR LARGE HAIL.  RELATIVELY LARGE

TEMPERATURE-DEWPOINT SPREADS COULD ALSO SUPPORT A FEW STRONG

DOWNDRAFTS AND AN ACCOMPANYING THREAT FOR DAMAGING WINDS.



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 26025.





...THOMPSON

