Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 151533 AAA AFDLWX Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 1033 AM EST Sun Jan 15 2017 .SYNOPSIS... High pressure will build over the area through tonight. A stationary front over the southern Mid-Atlantic states will move north as a warm front Tuesday. A weak cold front will push through the area Wednesday. && .NEAR TERM /THROUGH TONIGHT/...High pressure will build over the area through tonight setting up a cold air damming event. Low clouds will remain banked up against the mountains under northeast flow with light rain developing early this evening over the cntrl Shenandoah valley. Looking at hi-res models, NCAR 3-km 10-member ensemble and NAM-WRF 3-k parallel run, some pockets of fzra are possible only over the higher elevs of the Blue Ridge mtns and ridges in Shenandoah, Augusta and Rockingham counties. Farther north, where temperatures are likely to drop below freezing, no precip is expected. Have adjusted Wx and PoP grids for tonight keeping northern areas dry roughly north of the Potomac river. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Despite 1030mb surface high pressure building over the central mid- Atlantic tonight, upper level lift/a developing warm front associated with the SWrn low looks to bring rain into the area tonight. There is a chance for a wintry mix late tonight on the northern fringes of the precip shield that develops. High pressure shifts offshore Monday with the warm front lifting north of the area and return southerly flow developing. However, little mixing during the day likely makes for a cooler Monday than Sunday by a couple degrees. Low pressure moves NE across the Great Lakes Tuesday with another warm front entering the area. Areas of rain cross the area with a quarter to a half inch of rain. Perhaps this is enough to close the gap on our seasonal deficit. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... One thing seems clear - cold air will be held at bay for the extended part of the forecast in what is climatologically the coldest time of the year. Wednesday does look to start out showery as a short wave tracks through the Mid Atlantic followed by clearing Wednesday afternoon/ overnight. Highs should climb into the 50s with lows staying above freezing. Temperature-wise both Thursday and Friday should also see highs rise into the 50s. Models do begin to disconnect for the second half of the week - Euro has east coast under a ridge Thursday while GFS shows a trough moving through. While we are in fast upper level flow not sure the change is so rapid that another trough will move over us...and prefer the drier solution. By choosing the Euro depiction this would lead to the next short wave approaching the region Friday. Because of this have added low chance PoPs to the day. P-type would only be rain. This is still over five days away so there will likely be alteration to the forecast. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... IFR conditions now at KCHO only improving to MVFR this afternoon. No wintry precip expected at any of the TAF sites tonight. Light southerly flow develops Monday. Another warm front brings south winds, rain, and IFR conds Tuesday. Showers possible Wednesday then VFR Wednesday afternoon through Thursday. && .MARINE... High pressure moves overhead tonight with light southerly flow Monday through Tuesday. Winds expected to remain below SCA values Wednesday and Thursday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ Update...LFR Products...BAJ/Woody! is the U.S. government's official web portal to all federal, state and local government web resources and services.