Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 151402 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1002 AM EDT Sun Oct 15 2017 .SYNOPSIS... High pressure over the area will weaken rapidly through today. A cold front will push into the Mid Atlantic tonight followed by a return to high pressure early in the week and hold through the end of the week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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The day started with widespread low clouds, areas of drizzle, and patchy fog. The 12z LWX RAOB depicts a 2000 ft thick saturated layer trapped beneath a surface inversion. This is thicker than forecast yesterday, so it will take longer than previously advertised to erode. On the bright side, literally, satellite pictures do indicate mostly clear skies west of the Blue Ridge, aside from a patch of clouds acrpss the Potomac Highlands. This is further along than this time yesterday, and mixing should be better. Combining these two puzzle pieces suggest clearing by/during early afternoon, which is what short-ranged consensus forecasts predict. Have therefore gone cloudier than going forecast. Cloudier will mean cooler as well. High temperatures forecasts in the Shenandoah Valley have been left close to unchanged. However, backed DC/Baltimore metro forecasts down to mid-upper 70s...again, with support of short-term consensus guidance.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... Cdfnt will cross the area this evening with showers likely in the west early and then spreading east overnight. Gusty NW winds will also accompany the front. Showers will linger across srn MD through late morning Mon. Then, clearing Mon afternoon with breezy NW winds with gusts up to 25 mph. Much cooler Mon and Mon night. Winds diminish Mon night under building high pressure. Areas of frost will be possible Tue morning as temperatures drop to the mid 30s under clear skies and light winds. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... There`s little change in the 00Z guidance for the extended forecast period, and thus still little in the way of weather impacts. While its center will wobble some, high pressure will remain squarely over the area through the end of the week. A weak/decaying cold front will pass through New England late in the week, which will turn winds to the north, but otherwise have little moisture or thermal contrast. Aloft, the pattern will continue to amplify into a west coast trough/east coast ridge by Friday and Saturday. Temperatures will be 5-10 degrees above normal through the period. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/...
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Low clouds and some fog affecting the terminals. Anticipate gradual clearing through midday, with VFR CHO/MRB by noon, and metro hubs during the early afternoon. A cold front will cross the area this evening with a chance of showers. Winds shift and become NW with gusts up to 25 kt Sun night and Mon. Winds begin to diminish Tue. No significant weather expected Wednesday and Thursday with high pressure.
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&& .MARINE...
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SCA conditions expected later today through midday Tue. Gusts up to 30 knots expected over the lower Bay Mon. Light winds are expected Wednesday and Thursday with high pressure over the region.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ530>534- 537>543. Small Craft Advisory until 6 PM EDT Monday for ANZ535-536.
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&& $$ SYNOPSIS...LFR NEAR TERM...HTS SHORT TERM...LFR LONG TERM...ADS AVIATION...HTS/LFR/ADS MARINE...LFR/ADS

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