URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 575
NWS STORM PREDICTION CENTER NORMAN OK
120 PM EDT THU AUG 5 2010
THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
DISTRICT OF COLUMBIA
CENTRAL AND SOUTHERN DELAWARE
MARYLAND
NORTHWEST NORTH CAROLINA
VIRGINIA
SOUTHEAST WEST VIRGINIA
COASTAL WATERS
EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 120 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 85
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES WEST SOUTHWEST OF BLUEFIELD WEST VIRGINIA TO 50 MILES EAST OF PATUXENT RIVER MARYLAND. 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.
OTHER WATCH INFORMATION...CONTINUE...WW 574...
DISCUSSION...THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE/INTENSITY EARLY THIS AFTERNOON IN ADVANCE OF A SURFACE COLD
FRONT AS STRONG SURFACE HEATING CONTINUES TO DESTABILIZE THE BOUNDARY LAYER. MLCAPE HAS NOW INCREASED TO NEAR 3000 J/KG OVER MUCH OF VA...IN AN ENVIRONMENT SUPPORTIVE OF ORGANIZED MULTICELL CLUSTERS/LINE SEGMENTS ON THE SRN FRINGE OF THE STRONGER MIDLEVEL WLY FLOW. GIVEN THE MODERATE-STRONG INSTABILITY AND STEEP LOW-LEVEL LAPSE RATES...DAMAGING WINDS WILL BE LIKELY WITH THE STRONGER STORMS THROUGH LATE 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 28030.
...THOMPSON
