Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 021353 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 953 AM EDT SUN AUG 2 2015 .SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE WILL DOMINATE THE AREA THROUGH TONIGHT. A COLD FRONT WILL APPROACH THE AREA MONDAY BEFORE STALLING OUT OVERHEAD MONDAY NIGHT INTO TUESDAY. THE BOUNDARY WILL REMAIN NEARBY THROUGH THE END OF THE WEEK WHILE A WAVE OF LOW PRESSURE RIDES ALONG IT...BRINGING UNSETTLED CONDITIONS ESPECIALLY DURING THE LATTER HALF OF THE WEEK.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN TODAY. HOWEVER...A PESKY INVERSION HAS TRAPPED SOME MID-LEVEL MOISTURE OVER MUCH OF THE AREA...RESULTING IN A MID-LEVEL CLOUD DECK. SOME GUIDANCE CLEARS THIS OUT DURING THE AFTERNOON...WHILE OTHERS KEEP THE CLOUDS AROUND MUCH OF THE DAY. INCREASED SKY COVER FOR THIS MORNING AND MUCH OF THE AFTERNOON AS A RESULT. WEST-SOUTHWEST FLOW WILL HELP TEMPERATURES RISE INTO THE 80S IN MOST LOCATIONS...EXCEPT LOW 90S IN THE IMMEDIATE WASHINGTON DC/BALTIMORE METRO. IT SHOULD BE NOTED THAT IF CLOUDS ARE PERSISTENT ENOUGH...HIGHS MAY END UP A BIT LOWER THAN EXPECTED. OVERNIGHT LOWS WILL DIP BACK INTO THE UPPER 50S TO MIDDLE 60S WEST OF THE BLUE RIDGE TO THE UPPER 60S TO LOWER 70S EAST OF THE BLUE RIDGE...SLIGHTLY MILDER OVER THE METRO CENTERS. SOME PATCHY FOG IS POSSIBLE OVERNIGHT INLAND AND AWAY FROM THE METRO.
-- End Changed Discussion --
&& .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
UPPER TROUGH AND COLD FRONT WILL APPROACH FROM THE WEST. AHEAD OF THE FRONT...SOUTH TO SOUTHWEST FLOW WILL INCREASE AND TEMPERATURES WILL BECOME HOT. AFTERNOON READINGS WILL LIKELY REACH THE 90S IN MOST AREAS. HOWEVER...LOW DEW POINTS SHOULD KEEP US FROM REACHING HEAD ADVISORY LEVELS...WITH MOST DEW POINTS STAYING WELL WITHIN THE 60S. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE FROM WEST TO EAST VERY LATE IN THE DAY. A WEAK COLD FRONT WILL MOVE INTO THE REGION MONDAY NIGHT AND IT IS EXPECTED TO STALL OUT OVERHEAD FOR TUESDAY AND TUESDAY NIGHT. A COUPLE SHOWERS AND THUNDERSTORMS MAY IMPACT THE AREA MONDAY NIGHT...ESPECIALLY ACROSS NORTHERN MARYLAND AND THE POTOMAC HIGHLANDS WHERE FORCING MAY BE A BIT STRONGER ALONG THE BOUNDARY. MIN TEMPS MONDAY NIGHT WILL RANGE FROM THE 50S/60S IN THE POTOMAC HIGHLANDS TO THE MID AND UPPER 70S IN DOWNTOWN WASHINGTON AND BALTIMORE. IF SOME CLEARING OCCURS LATE...PATCHY FOG WILL ONCE AGAIN BE A CONCERN INLAND AND AWAY FROM THE METRO. THE STALLED BOUNDARY OVER THE AREA WILL BE WEAK TUESDAY AND TUESDAY NIGHT. THEREFORE...LITTLE TEMPERATURE GRADIENT IS EXPECTED ALONG THE BOUNDARY. THERE WILL BE A DEWPOINT GRADIENT AND WITH HIGHER DEWPOINTS SOUTH OF THE BOUNDARY A COUPLE SHOWERS AND THUNDERSTORMS MAY POP UP TUESDAY AFTERNOON AND EVENING...MAINLY ACROSS CENTRAL VIRGINIA INTO SOUTHERN MARYLAND. EVEN ACROSS THESE AREAS CONVECTION IS EXPECTED TO REMAIN ISOLATED/SCATTERED SINCE THE BOUNDARY WILL BE WEAK. ANY CONVECTION SHOULD DISSIPATE OVERNIGHT TUESDAY WITH THE LOSS OF DAYTIME HEATING.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE BOUNDARY WILL REMAIN NEARBY WEDNESDAY THROUGH SATURDAY. A ZONAL FLOW ALOFT WILL SEPARATE UPPER-LEVEL LOW PRESSURE OVER CANADA FROM AN UPPER-LEVEL RIDGE OVER THE SOUTH-CENTRAL CONUS INTO THE ATLANTIC OCEAN. A SERIES OF DISTURBANCES WILL ROTATE THROUGH THE AREA IN THE ZONAL FLOW ALOFT. THESE DISTURBANCES WILL INTERACT WITH THE FRONTAL BOUNDARY...INCREASING THE CHANCE FOR SHOWERS AND THUNDERSTORMS. TIMING OF THESE ARE UNCERTAIN THIS FAR OUT...BUT GUIDANCE INDICATES THAT THE BEST CHANCE FOR CONVECTION MAY BE WEDNESDAY NIGHT AND THURSDAY...AND POSSIBLY AGAIN LATER FRIDAY INTO SATURDAY. AGAIN...TIMING THIS FAR OUT IS HIGHLY UNCERTAIN. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
VFR TO PERSIST TODAY INTO MONDAY...WITH JUST SLIGHT CHANCE OF REDUCED CIGS/VIS IN PATCHY FOG AT MRB/CHO. WINDS WILL INCREASE OUT OF THE SOUTH TO SOUTHWEST ON MONDAY. WIND SPEEDS IN THE 10-15KT RANGE WILL BE POSSIBLE. SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS MAY DEVELOP MONDAY EVENING AND PERSIST INTO THE OVERNIGHT. A WEAK COLD FRONT WILL STALL OVER THE AREA MONDAY NIGHT AND IT WILL REMAIN NEARBY THROUGH THURSDAY. A SHOWER OR THUNDERSTORM IS POSSIBLE MONDAY NIGHT AND TUESDAY...BUT MOST OF THE TIME WILL BE DRY. THERE IS A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS ALONG WITH REDUCED CIGS/VSBYS WEDNESDAY NIGHT AND THURSDAY.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
WINDS WILL REMAIN BELOW SCA TODAY INTO TONIGHT BUT WILL INCREASE WITH SOUTHERLY CHANNELING ON MONDAY. SMALL CRAFT CONDITIONS ARE NOW EXPECTED...AND SCA HAS BEEN ISSUED. A COLD FRONT WILL STALL OUT NEAR THE WATERS MONDAY NIGHT AND IT WILL REMAIN NEARBY THROUGH THE END OF THE WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS MONDAY NIGHT INTO TUESDAY. A SERIES OF DISTURBANCES WILL RIDE ALONG THE BOUNDARY...INCREASING THE CHANCES FOR SHOWERS AND THUNDERSTORMS DURING THE LATTER PORTION OF THE WEEK.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING... ASTRONOMICAL TIDES ARE HIGHER DUE TO THE NEARLY-FULL MOON...BUT ANOMALIES ARE LOW ENOUGH THAT TIDAL FLOODING WILL NOT BE A THREAT THROUGH TODAY. SOUTHERLY FLOW AHEAD OF THE NEXT FRONT WILL ELEVATE TIDAL ANOMALIES ON MONDAY...BUT AT THIS POINT NOT EXPECTING MINOR FLOODING. THIS POSSIBILITY WILL REQUIRE MONITORING HOWEVER. && .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON MONDAY TO 6 AM EDT TUESDAY FOR ANZ530>534-537>543. SMALL CRAFT ADVISORY FROM 3 PM MONDAY TO MIDNIGHT EDT MONDAY NIGHT FOR ANZ535-536.
-- End Changed Discussion --
&& $$ SYNOPSIS...BJL NEAR TERM...KRW/RCM SHORT TERM...BJL/KRW/RCM LONG TERM...BJL AVIATION...BJL/KRW/RCM MARINE...BJL/KRW/RCM TIDES/COASTAL FLOODING...

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.