Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 071521 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1021 AM EST Wed Dec 7 2016 .SYNOPSIS...
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High pressure builds into the area today. A cold front will move through Thursday. High pressure returns to the area Friday into the weekend. Another cold front crosses the area early next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Weak high pressure will build into the region this afternoon/ tonight. Max temps will range from the upper 30s to lower 40s in the mountains to the mid 50s I-95 and east. A reinforcing cold front will pass through the Ohio Valley late tonight while a potent jetmax in the upper-level flow builds in from the southwest. This will bring some clouds overnight...but little moisture will be in place so the forecast is dry.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
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The jetmax will pass through the area Thursday and the reinforcing cold front will also pass through the area during this time. Again...moisture remains limited so most areas may end up dry. However...a couple showers cannot be ruled out ahead of the boundary. Will continue with slight pops across southern Maryland where the forcing and moisture have the best chance to line up. Even across these areas...any precipitation should be light and much of the day will turn out dry. Canadian high pressure will build toward the area Thursday night through Friday night. Blustery northwest flow will allow for colder conditions. Upslope snow showers are likely for locations along and west of the Allegheny Front. Accumulations are also likely during this time. Elsewhere...dry conditions should persist.
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&& .LONG TERM /SATURDAY THROUGH TUESDAY/...
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Overall upper level pattern will be primarily zonal for the extended. Fast changes to the weather...no big storms. Artic high pressure shifts overhead during the day Saturday. Highs across much of the area remaining AOB 40F (i.e., around 10F below normal). With high pressure overhead...expect lows early Sunday morning in the 20s everywhere. High pressure shifts offshore Sunday. With a southerly wind component developing...highs reach back into the L/M40s across much of the area. Cold front approaches the area early next week...with most guidance bringing precipitation in late Sunday into Monday. Winter p-type issues of all varieties could arise with this system...though it is too early to determine areal extent of any threat. Additionally, large QPF spread exists among long range ensemble guidance. High pressure returns to the area in the wake of frontal passage late Monday into Tuesday...with dry weather returning...albeit briefly.
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&& .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
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VFR conditions will prevail today through this evening. An upper- level disturbance may bring a period of MVFR cigs late tonight into Thursday across the eastern terminals...but confidence is low at this time. Otherwise...more VFR conditions are expected through Friday night. Gusty northwest winds are expected behind a cold front Friday. VFR conditions prevail Saturday through much of Sunday as high pressure remains over the area. Some flight restrictions could develop by early Sunday evening as precipitation begins to move back into the area.
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&& .MARINE...
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High pressure approaches from the west today. A northwest flow is expected today and a Small Craft Advisory is in effect for the lower Potomac and widest part of the Ches Bay. High pressure will build overhead tonight and light winds are expected. A reinforcing cold front will pass through late Thursday into Thursday night. Gusty northwest winds are expected behind the boundary. A Small Craft Advisory may be needed Thursday afternoon...but confidence is low due to timing uncertainties. A Small Craft Advisory will be needed Thursday night through Friday night...and a Gale Warning may be needed for portions of the waters Friday. However...latest information suggest that SCA conditions are more likely than Gale Conditions. Winds drop back below SCA Saturday morning as large area of high pressure builds overhead. Low-end SCA wind gusts could redevelop Sunday afternoon in southerly flow ahead of cold front.
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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 EST this afternoon for ANZ534- 537-543.
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&& $$ UPDATE...WOODY! PREVIOUS...BJL/MSE

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