Post by Nws Olney Maryland on Aug 16, 2010 13:28:20 GMT -5
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 620
NWS STORM PREDICTION CENTER NORMAN OK/OLNEY MD
215 PM EDT MON AUG 16 2010
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
DISTRICT OF COLUMBIA
CENTRAL AND EASTERN MARYLAND
NORTHERN VIRGINIA
FAR EASTERN WEST VIRGINIA
COASTAL WATERS
EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 215 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 40 MILES NORTH
NORTHWEST OF BALTIMORE MARYLAND TO 50 MILES SOUTHEAST OF
CHARLOTTESVILLE 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 619...
DISCUSSION...TSTMS DEVELOPING ALONG THE BLUE RIDGE SHOULD CONTINUE
TO INTENSIFY WHILE PROGRESSING EWD/SEWD INTO A HOT AND MODERATELY
UNSTABLE AIR MASS WITH MLCAPE OF 2000-2500 J/KG. 17Z IAD SOUNDING
LIKELY REPRESENTS A GOOD PROXY FOR THERMODYNAMIC AND KINEMATIC
ENVIRONMENT ACROSS THE AREA...THOUGH MODEL GUIDANCE AND
OBSERVATIONAL DATA SUGGEST VERTICAL SHEAR DIMINISHES WITH SWD
EXTENT. AS SUCH...GIVEN ENVIRONMENT WILL BE SUPPORTIVE OF ORGANIZED
MULTICELL AND PERHAPS SUPERCELL STORM MODES WITH THE PRIMARY HAZARD
BEING DAMAGING WIND GUSTS.
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 28025.
SEVERE THUNDERSTORM WATCH NUMBER 620
NWS STORM PREDICTION CENTER NORMAN OK/OLNEY MD
215 PM EDT MON AUG 16 2010
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
DISTRICT OF COLUMBIA
CENTRAL AND EASTERN MARYLAND
NORTHERN VIRGINIA
FAR EASTERN WEST VIRGINIA
COASTAL WATERS
EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 215 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 40 MILES NORTH
NORTHWEST OF BALTIMORE MARYLAND TO 50 MILES SOUTHEAST OF
CHARLOTTESVILLE 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 619...
DISCUSSION...TSTMS DEVELOPING ALONG THE BLUE RIDGE SHOULD CONTINUE
TO INTENSIFY WHILE PROGRESSING EWD/SEWD INTO A HOT AND MODERATELY
UNSTABLE AIR MASS WITH MLCAPE OF 2000-2500 J/KG. 17Z IAD SOUNDING
LIKELY REPRESENTS A GOOD PROXY FOR THERMODYNAMIC AND KINEMATIC
ENVIRONMENT ACROSS THE AREA...THOUGH MODEL GUIDANCE AND
OBSERVATIONAL DATA SUGGEST VERTICAL SHEAR DIMINISHES WITH SWD
EXTENT. AS SUCH...GIVEN ENVIRONMENT WILL BE SUPPORTIVE OF ORGANIZED
MULTICELL AND PERHAPS SUPERCELL STORM MODES WITH THE PRIMARY HAZARD
BEING DAMAGING WIND GUSTS.
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 28025.