Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 251832 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 232 PM EDT Tue Jul 25 2017 .SYNOPSIS...
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High pressure will build into the Mid Atlantic tonight before moving offshore Wednesday. A cold front will approach the area Thursday before passing through Friday into Friday night. High pressure is expected to return for the weekend.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Bkn-ovc low clouds over the northern half of the fcst area early this evening. As high pres builds to the north, winds will take a more easterly component with a marine layer potentially developing along the western shore of the Chesapeake Bay late tonight. A few showers or sprinkles may develop along the shore. Patchy dense fog may also develop over the valleys west of the Blue Ridge mtns.
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&& .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
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Low Fog/stratus will mix out during the late morning or early afternoon Wed. No wx is expected in the afternoon as subsidence inversion will remain quite strong. A warm front will lift through the area Thu with warm humid air moving in. Scattered showers/t-storms expected in the afternoon mainly in the west, then widespread showers/t-storms Thu night into at least the first half of Fri as wave of low pressure moves across. Still uncertainty in timing of frontal wave moving across and instability available given expected widespread clouds and showers. Both a severe and flash flooding risk are present with flash flooding having higher odds at this time given potential for repeated activity.
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&& .LONG TERM /SATURDAY THROUGH TUESDAY/...
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A closed upper level low is forecast to swing across the Mid- Atlantic region Saturday. Low pressure along a cold front will likely be moving south of the Mid-Atlantic region. Showers may linger into Saturday until the upper level trough axis swings through by Saturday evening. High pressure will move into the region behind the departing sfc low Saturday night. High pressure will likely be in control into the start of the work week.
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&& .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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Bkn cigs 040 into early evening. A period of clear skies expected this evening with stratus expected to develop at BWI and MTN. Patchy light fog also possible at CHO and MRB. Showers and t-storms likely Thu night and Fri with flying restrictions likely at some point. Improving weather Saturday night into Sun.
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&& .MARINE...
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Winds will continue to diminish through Wed night and begin to strengthen Thu afternoon into Sat. SCA conditions are possible during this time. SMWs may also be required due to potential for convection. Small craft conditions possible Saturday into Sunday, but winds should be on the downward trend by Sat night.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...None.
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&& $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...MM/LFR LONG TERM...BJL/HSK AVIATION...MM/HSK/LFR MARINE...HSK/LFR

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