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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 181855 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 255 PM EDT Mon Jul 18 2016 .SYNOPSIS... A surface trough will remain over the region today and a cold front will approach from the north tonight. The cold front will slowly pass through the area Tuesday through Tuesday night. High pressure will build overhead for Wednesday and Thursday. High pressure over the Atlantic will control the weather pattern for late in the week before a cold front approaches the area early next week. && .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
A line of showers and thunderstorms will move across the Mid- Atlantic region this afternoon. A severe thunderstorm watch is in effect for most of the region. Heat and moisture have led to high instability and thunderstorms have been able to tap into this as they move eastward. The best shear is further north across New England but isolated strong to severe thunderstorms are expected through 8pm tonight. Instability ahead of the line of activity will also lead to scattered pop-up showers and thunderstorms. A cold front will move southward across the Ohio Valley tonight and mild temperatures and moisture will stay around the region through tonight. Showers and a brief thunderstorm are possible over night with the best chance across the Central Foothills east to Southern Maryland. Clearing of sky cover is also possible overnight and result in fog forming into Tuesday morning. The cold front is expected to slowly move southward overnight however winds will be light slowing the dry air from pushing into the region.
-- End Changed Discussion --
&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
The cold front should be located across Central Virginia Tuesday morning and is expected to stay nearly stationary through Tuesday which will result in dewpts elevated especially across the southern half of the outlook area and isolated showers and thunderstorms may initiate into the afternoon. Thunderstorms are expected to stay sub-severe at this time. Northerly winds should finally elevate humidity Tuesday night with dewpts dropping into the 50s from NW to SE. High pressure will build into the region Wednesday and dry conditions are expected. Temps will climb into the mid 80s by the afternoon with low dewpts giving a quick break from the heat and humidity.
-- End Changed Discussion --
&& .LONG TERM /THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
While it remains dry, heat returns Thursday and Friday on south/southwesterly flow. Humidity still relatively mild Thursday (L60s)...but dewpoints return into the M/U60s by Friday. Hot and humid this weekend...with heat indices AOA 100F Saturday and near 100F Sunday. Diurnal shower and storm chances return with the increasing heat and humidity.
-- End Changed Discussion --
&& .AVIATION /18Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
A line of showers and thunderstorms will continue to move across the terminals this afternoon and early evening. Heavy rain and gusty winds are the main threats resulting in mvfr/ifr conditions are they move through the terminals. VFR conditions expected behind line and as SHRA taper off into the evening hours. A stray shower or thunderstorm cant be ruled out at CHO overnight. Fog is also possible at the terminals tonight and into Tuesday morning and may result in sub-vfr conditions. VFR conditions expected Tuesday and into Wednesday as high pressure builds into the region. A cold front may push back into the region Tuesday afternoon and showers and thunderstorms are possible mainly across CHO. VFR expected Thursday through the weekend. Though, a few showers/storms possible Saturday and Sunday in the hot and humid airmass.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Southerly winds expected on the waters today. SCA is in effect through the early evening. Winds will taper off tonight. Showers and thunderstorms expected this afternoon and evening and gusty winds are possible. SMW may be issued in thunderstorm activity. Activity will taper off tonight however a stray shower and thunderstorm cant be ruled out through Tuesday afternoon. A cold front will pass through the waters Tuesday into Tuesday night. A few showers and thunderstorms are possible ahead of the boundary...especially across the middle portion of the Bay into the Potomac River. Locally gusty winds are possible in any thunderstorms that do develop. High pressure will build overhead Wednesday into Wednesday night. A pressure surge behind the cold front may cause winds to gust near SCA criteria overnight Tuesday into Wednesday morning. Mostly sub-SCA conditions expected for the end of the week and weekend, however brief intervals of gusts up to around 20 knots possible each night.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 9 PM EDT this evening for ANZ530>543. && $$ SYNOPSIS...HAS NEAR TERM...HAS SHORT TERM...BJL/HAS LONG TERM...MSE AVIATION...HAS/MSE MARINE...HAS/MSE

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