

717 

WWUS20 KWNS 261812

SEL5

SPC WW 261812

DCZ000-DEZ000-MDZ000-NJZ000-VAZ000-CWZ000-270100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 625

NWS STORM PREDICTION CENTER NORMAN OK

210 PM EDT SUN JUL 26 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       DELAWARE

       MUCH OF MARYLAND

       SOUTHERN NEW JERSEY

       CENTRAL AND EASTERN VIRGINIA

       COASTAL WATERS



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 210 PM UNTIL 900

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 85

STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES EAST

SOUTHEAST OF SOUTH HILL VIRGINIA TO WILMINGTON DELAWARE.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU5).



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.



DISCUSSION...STORMS HAVE RECENTLY DEVELOPED OVER SWRN VA AND ARE

EXPECTED TO INCREASE IN COVERAGE AND INTENSIFY THROUGH THE REMAINDER

OF THE AFTERNOON...AS THEY DEVELOP AND SPREAD NEWD INTO A MORE MOIST

AND UNSTABLE BOUNDARY LAYER. DEEP SWLY WINDS ABOVE THE BOUNDARY

LAYER WILL BE SUPPORTIVE OF LINE SEGMENTS/POSSIBLY BOWS...AND IN

COMBINATION WITH THE STEEP LOW LEVEL LAPSE RATES...WIND DAMAGE

SHOULD BE THE PRIMARY THREAT. HOWEVER...THE DEGREE OF

INSTABILITY...MLCAPES UP TO 3000 J/KG...WILL SUPPORT SEVERE HAIL

ALSO.



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 25025.





...IMY

