

000 

WWUS20 KWNS 191902

SEL0

SPC WW 191902

DCZ000-MDZ000-NYZ000-OHZ000-PAZ000-VAZ000-WVZ000-CWZ000-200300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 420

NWS STORM PREDICTION CENTER NORMAN OK

305 PM EDT TUE JUN 19 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       NORTHERN MARYLAND

       PARTS OF SOUTHEAST NEW YORK

       PARTS OF SOUTHEAST OHIO

       MUCH OF SOUTHERN PENNSYLVANIA

       PARTS OF NORTHERN VIRGINIA

       PARTS OF CENTRAL AND EASTERN WEST VIRGINIA

       COASTAL WATERS



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 305 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 95

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

OF ALLENTOWN PENNSYLVANIA TO 10 MILES NORTH OF CHARLESTON WEST

VIRGINIA.  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 417...WW 418...WW 419...



DISCUSSION...THUNDERSTORMS WILL INCREASER IN NUMBER AND INTENSITY

ACROSS THE WATCH AREA REMAINDER OF THE AFTERNOON AS STRONG HEATING

CONTINUES IN A MDTLY UNSTABLE AIR MASS. WITH APPROACH OF TROUGH AND

COLD FRONT FROM THE WEST..STORMS WILL DEVELOP INTO SHORT

LINES/CLUSTERS INCREASING WIND DAMAGE POTENTIAL LATE THIS

AFTERNOON/EVENING.



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 550. MEAN STORM

MOTION VECTOR 25020.





...HALES

