Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 211856 AAA AFDLWX Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 256 PM EDT Sat Oct 21 2017 .SYNOPSIS...High pressure will move east into the western Atlantic through Monday. Low pressure and its attendant cold front will sweep through the area Tuesday. Troughing will remain overhead for much of the second half of the week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... High pressure will remain in control surface and aloft. Quite a bit more of high clouds expected tonight than yesterday. Temps a bit warmer tonight due to more clouds. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... Quiet wx Sun-Sun night under high pressure. Clouds begin to increase Mon with showers expected by midday on the west and spreading east through the afternoon. Heavy showers with possible t-storms and gusty winds Mon night as cdfnt enters the area. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Strong front moving through Tuesday is main story in long term. This system looks potent with potential for a period of heavy, wind swept rain ahead of and along the primary cold front. Strong southerly fetch ahead of it should bring copious moisture north, but speed should limit flood concern. Gusty winds possible with very strong low level jet, but most likely any winds of a threatening nature will be limited to the cold frontal passage itself - low topped squalls possibly embedded within larger rain band is the concern. Timing remains a bit uncertain but right now, its favoring the AM. Breezy and much cooler behind the front, with the coolest days likely Wednesday-Thursday. Some freeze issues are possible, though this cold shot looks very transitory and if it doesn`t align with a good radiational night, it just might be chilly versus freezing. Upper trough plus wraparound moisture might result in a few showers Wednesday as well, especially in the mountains. If its cold enough in the higher terrain, these could well be snow showers. Drying out and moderating Friday with high pressure building in. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... Quiet wx through Sun night. Clouds increase Mon with showers expected Mon night. LLWS is also possible. Primary concern with TAFs in long term will be the strong front moving through Tuesday. Potential for heavy rain and IFR cigs/vis, along with LLWS and gusty winds - perhaps isolated 30-40 knot gusts. Timing still a bit uncertain but right now favoring the AM. After that, NW wind may be gusty, but becoming VFR overall for the rest of the week. A few showers possible, mainly Wednesday, but cig/vis reductions should be minimal. && .MARINE...Winds will begin to strengthen Mon in srly flow. SCA conditions likely by late Mon and solid SCA conditions expected Tue. Gales possible Tuesday as strong cold front barrells through. SCA possible Wednesday as the system moves away and high pressure builds in. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...RCM AVIATION...RCM/LFR MARINE...RCM/LFR is the U.S. government's official web portal to all federal, state and local government web resources and services.