Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 231851 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 151 PM EST Thu Nov 23 2017 .SYNOPSIS... High pressure will build over the area through Friday. Another cold front will approach overnight Friday into Saturday before passing through Saturday night. High pressure returns for Sunday and Monday before moving offshore Tuesday. && .NEAR TERM /THROUGH FRIDAY/... Three years ago on Thanksgiving, we had a little snow on the ground at the start of the day in portions of the area, and some light rain/snow showers during the day. This year, Thanksgiving Day features some of the quietest weather you`ll find around here. A bit chilly, yes; but otherwise it`d be hard to expect better weather for a holiday. For folks getting out and about this afternoon/evening, temperatures will be falling through the 30s under a mostly clear to clear sky with light winds, as high pressure remains over the area. With winds going calm in many areas, decoupling of the boundary layer is expected. Low temps may be a couple degrees warmer than this morning, but it`s still going to be chilly and I went on the low end of (if not below) all guidance. Friday will be a warmer day than today with some light return flow developing as high pressure shifts south and east of the area. Most areas will see highs between 50 and 55. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... A cold front will be approaching from the Ohio Valley by Friday night, with a gradual increase in clouds after midnight from west to east. At this point it appears all precipitation will remain west of the Divide through daybreak Saturday, but the southerly winds will allow us to remain above freezing all night. The cold front moves through the area on Saturday, but the orientation of the system turns the winds from the west as it passes through, causing rapid drying and downsloping. Thus the best rain chances are in the Highlands and Shenandoah Valley, though a slight chance of a brief light shower is in the forecast further east. Probably not something that should change your plans if you`re in the major population centers though. The pressure gradient tightens behind the front on Saturday night, which will increase winds to the 10-20 mph range. Not exactly cold behind the front though (other than the way it feels with the breeze), with lows still staying above freezing. The persistent west winds will promote upslope snow west of the Allegheny Front, with early indications of light accumulations possible based on our probabilistic snow output. && .LONG TERM /SUNDAY THROUGH THURSDAY/... High pressure will dominate the region through Tuesday. Dry conditions with plenty of sunshine and temperatures that will be near or a few degrees below average are expected through the period. The high moves offshore Tuesday night to allow for a dry cold front to slide across the region to the Tidewater of Virginia Wednesday. Temperatures will be a couple of degrees milder. A second area of high pressure will wedge itself southeastward behind the cold front Wednesday night into Thursday. Temperatures will be near average. We can`t rule out a couple of upslope rain showers over the Appalachian Mountains or Blue Ridge Thursday with a slight chance of rain showers across eastern Virginia and southern Maryland as a possible weak low pressure system moves north along the Carolina Coast. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... Absolutely no flight restriction concerns for the terminals through Friday night. Clouds increase Saturday morning with a chance for a shower, mainly at MRB. Gusty winds 10-20 mph Saturday night. VFR conditions Sunday through Tuesday. && .MARINE... Light winds expected on the waters through Saturday. Behind a cold front on Saturday night, winds will markedly increase and a small craft advisory is almost certain for Saturday night into Sunday. No marine hazards Sunday night through Monday night. Could see some gusts above small craft on the open Bay waters on Tuesday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...JE NEAR TERM...JE SHORT TERM...JE LONG TERM...KLW AVIATION...JE/KLW MARINE...JE/KLW is the U.S. government's official web portal to all federal, state and local government web resources and services.