Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 221839 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 239 PM EDT Mon Aug 22 2016 .SYNOPSIS... High pressure will build eastward from the Ohio Valley today. The high will gradually shift eastward though the week ahead before a cold front crosses the area on Friday. High pressure behind that front will dominate through the weekend. && .NEAR TERM /THROUGH TONIGHT/...
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High pressure still over the Ohio Valley this afternoon. Cumulus clouds have developed in daytime heating, but with very little vertical extent. Also still have some gusts in the mid teens. They have outlived the window offered by model guidance, so have to believe that the gradient will relax soon. The center of the high willl drift toward the area tonight. Guidance suggesting that some moisture may get trapped under subsidence inversion. Am still not stressing that solution too heavlily, but it will be something to focus upon. If it happens, low temperatures will be warmer. For that reason, did not emphasize radiational cooling too much.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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Transitory high pressure will be the focus for Tuesday and Wednesday. Expect benign conditions for the midweek. By Wednesday, we will begin to see return flow, so dewpoints (and temperatures) will start to creep upward by Wednesday. It will still be seasonably pleasant.
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&& .LONG TERM /THURSDAY THROUGH MONDAY/...
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High pressure slides off the coast on Thursday as a cold front approaches Thursday night. Some showers could develop ahead of the front, mainly over our western counties. Main showers and thunderstorms activity expected Friday as cold front moves across our CWA. The front will slowly moves south Saturday into Sunday as high pressure builds in, bringing cooler and drier weather. Surface easterly flow could enhance some afternoon shower and thunderstorm activity on Sunday, mainly west of the Blue Ridge. Dry conditions expected on Monday as high pressures moves across the Mid-Atlantic and off the coast. High temperatures will be in the upper 80s and low 90s... with Friday having the highest heat indexes in the upper 90s.
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&& .AVIATION /19Z MONDAY THROUGH SATURDAY/...
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VFR through Wednesday. Guidance suggesting that the current cumulus may lead to clouds trapped under a subsidence inversion. Even if that were to transpire, ceilings would be FL050. At this time, am still not forecasting this solution. Showers and thunderstorms possible on Friday causing sub-VFR conditions. Mainly VFR conditions expected Saturday.
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&& .MARINE...
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Pressure gradient has held on. As a result, have had wind gusts in the mid teens, with occasional gusts close to Advisory criteria. Have been allowing SCA to expire on time; the last piece will drop at 3pm. Light winds tonight and tomorrow morning has high pressure passes overhead. South winds for Tuesday afternoon through Wednesday. However, do not believe that winds will be too much above 10 kt. Sub-SCA conditions expected between Thursday and Sunday with wind gusts below 15 kt. Some showers and thunderstorms possible on Friday.
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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 3 PM EDT this afternoon for ANZ534- 543.
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&& $$ SYNOPSIS...RCM NEAR TERM...HTS SHORT TERM...HTS LONG TERM...IMR AVIATION...HTS/IMR MARINE...HTS/IMR

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