Post by Nws Olney Maryland on Aug 21, 2011 13:03:02 GMT -5
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 794
NWS STORM PREDICTION CENTER OLNEY MD
1255 PM EDT SUN AUG 21 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
WESTERN CONNECTICUT
DISTRICT OF COLUMBIA
DELAWARE
MARYLAND
NEW JERSEY
EXTREME SOUTHEAST NEW YORK
CENTRAL AND EASTERN PENNSYLVANIA
NORTHERN VIRGINIA
THE EASTERN WEST VIRGINIA PANHANDLE
COASTAL WATERS
EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1255 PM UNTIL
900 PM EDT.
WIDESPREAD DAMAGING WINDS
ISOLATED WIND GUSTS TO 70 MPH POSSIBLE
SCATTERED LARGE HAIL TO 2.0 INCHES IN DIAMETER
ISOLATED TORNADOES
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH
NORTHEAST OF ALLENTOWN PENNSYLVANIA 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 WOU4).
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...THUNDERSTORMS WILL INCREASE IN COVERAGE/INTENSITY THIS
AFTERNOON IN CONJUNCTION WITH CONTINUED DAYTIME HEATING...AND AS A
MIDLEVEL TROUGH AND COLD FRONT MOVE EWD/SEWD ACROSS THE REGION.
ADDITIONALLY...A SURFACE LEE TROUGH FROM NRN VA TO ERN PA/SE NY WILL
HELP FOCUS THUNDERSTORM DEVELOPMENT. MODERATE-STRONG INSTABILITY
/MLCAPE AOA 2000 J PER KG/ AND INCREASING VERTICAL SHEAR THROUGH THE
AFTERNOON WILL BE FAVORABLE FOR STORMS TO PRODUCE DAMAGING WINDS AND
LARGE HAIL. A COUPLE OF SUPERCELLS MAY ALSO DEVELOP THIS AFTERNOON
NEAR THE LEE TROUGH...AND AN ISOLATED TORNADO WILL BE POSSIBLE WHERE
LOW-LEVEL SHEAR WILL BE SOMEWHAT STRONGER.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27035.
SEVERE THUNDERSTORM WATCH NUMBER 794
NWS STORM PREDICTION CENTER OLNEY MD
1255 PM EDT SUN AUG 21 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
WESTERN CONNECTICUT
DISTRICT OF COLUMBIA
DELAWARE
MARYLAND
NEW JERSEY
EXTREME SOUTHEAST NEW YORK
CENTRAL AND EASTERN PENNSYLVANIA
NORTHERN VIRGINIA
THE EASTERN WEST VIRGINIA PANHANDLE
COASTAL WATERS
EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1255 PM UNTIL
900 PM EDT.
WIDESPREAD DAMAGING WINDS
ISOLATED WIND GUSTS TO 70 MPH POSSIBLE
SCATTERED LARGE HAIL TO 2.0 INCHES IN DIAMETER
ISOLATED TORNADOES
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH
NORTHEAST OF ALLENTOWN PENNSYLVANIA 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 WOU4).
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...THUNDERSTORMS WILL INCREASE IN COVERAGE/INTENSITY THIS
AFTERNOON IN CONJUNCTION WITH CONTINUED DAYTIME HEATING...AND AS A
MIDLEVEL TROUGH AND COLD FRONT MOVE EWD/SEWD ACROSS THE REGION.
ADDITIONALLY...A SURFACE LEE TROUGH FROM NRN VA TO ERN PA/SE NY WILL
HELP FOCUS THUNDERSTORM DEVELOPMENT. MODERATE-STRONG INSTABILITY
/MLCAPE AOA 2000 J PER KG/ AND INCREASING VERTICAL SHEAR THROUGH THE
AFTERNOON WILL BE FAVORABLE FOR STORMS TO PRODUCE DAMAGING WINDS AND
LARGE HAIL. A COUPLE OF SUPERCELLS MAY ALSO DEVELOP THIS AFTERNOON
NEAR THE LEE TROUGH...AND AN ISOLATED TORNADO WILL BE POSSIBLE WHERE
LOW-LEVEL SHEAR WILL BE SOMEWHAT STRONGER.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27035.