Area Forecast Discussion
Issued by NWS Wakefield, VA

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875 FXUS61 KAKQ 040018 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 718 PM EST Sat Dec 3 2016 .SYNOPSIS... High pressure builds across the region tonight and Sunday. Low pressure passes south of the region Sunday night into Monday. A complex area of low pressure crosses the region Tuesday. A strong cold front crosses the area Thursday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Sfc high slides east invof Mason-Dixon line tonight. Tsctns show high level moisture overspreading the region ahead of the developing low to the south. Thus, expect mstly clr/partly cloudy skies this evening becoming mstly cloudy across the west late. Temps quickly drop after sunset then level off. Lows in the low- mid 30s except upr 30s along the sern beaches. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... High pressure slides east at a position along the Delmarva Sunday aftn. While this high keeps it dry in the lower levels, the mid/upr levels quickly moisten throughout the day. So while there could be some dim sunshine early Sun morning across the east, expect the day to turn out cloudy to mostly cloudy with any pcpn remaining sw of the fa thru 00Z Mon. The clouds hold temps down with highs in the upr 40s-lwr 50s. First wave of energy from the low over the deep south ejects ENE along a developing trof over the Carolinas Sunday night. Models agree in quickly spreading moisture NE across the fa Sun evening. Best lift/support progged over the SERN half of the fa where greatest QPF will be (1/4 to 1/3rd inch). Will carry chc/likely pops during the evening then ramp up to likely pops most areas except categorical pops across SERN zones after midnight. In-situ wedge leads to a chilly rain with lows in the upr 30s-lwr 40s. The sfc low pushes off the coast near HAT Monday morning with weak ridging building south across the area throughout the day. Despite the high pressure building in, TSCTNS show enough leftover moisture at various levels to keep cloudy to mostly cloudy skies. Chc pops in the morning (except likely across extreme SE zones) lower to slght chc across NC zones in the afternoon. Highs in the low-mid 50s. Timing differences arise wrt the pcpn arrival Monday night with the NAM the fastest, GFS the slowest with the 12Z ECMWF a compromise between the two. Will lean toward the faster solution given pcpn usually breaks out a bit faster given an overrunning scenario. Will carry low chc pops Monday eve ramping up to chc to likely pops after midnight. Lows in the mid 30s NW to upr 40s SE. Tuesdays forecast is another typical Mid Atlantic system where low pressure tracks NE along the mts with a secondary low tracking NE along the coast. Copious amounts of both GOM/Atlantic moisture will fall into a strong wedge across the piedmont. Expect a wide temp range across the fa along with a much needed/widespread rainfall. Challenge will be to define where the coastal low tracks as the NAM has an inland track with both the GFS/ECMWF tracking the low right along the coast. For now, will keep all pcpn stratiformed with categorical pops. QPF averaging btwn 1/2 to 3/4 inches. Temps tricky but will continue with a sharp thermal gradient. Highs from mid-upr 40s across the wedged piedmont to near 60 across sern coastal zones. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Long term period starts off wet with double-barrel low pressure passing through the region and W/SW flow aloft. The best chance of rain will be Tue eveng, with the rain possibly lasting into the overnight hours and Wed morning depending on how fast the sfc low pushes offshore. For now will maintain chance pops over far eastern areas Wed, with high temps in the mid 50s. There will also be a chance of rain Thu with a passing strong cold front, although the chances and qpf are expected to be lower than with the system earlier in the week. Hi temps Thu in the low/mid 50s. With a slower cold fropa and some anafrontal pcpn, there is also a chance of some snow showers over NE areas Thu night. Dry weather thereafter for Fri and Sat as sfc high pressure builds in from the west. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... High pressure slides out of the Ohio Valley and directly over the Mid Atlantic Region tonight into Mon. VFR conditions will persist with high cirrus increasing and thickening through the day on Mon. The sfc high (and subsequent stacked ridging aloft) slides offshore by Monday evening. This will allow steady rain to overspread the area from sw-ne late in the evening and overnight as shortwave energy streams into the area via the upper ridge which is also flattening overnight. MVFR to IFR cigs/vis (and maybe even LIFR conditions) should be anticipated. Meanwhile, sfc low pressure develops along the Southeast Coast early Mon and slowly exits off Cape Hatteras the rest of Mon. High pressure briefly returns to the region Mon night...followed by a more well-defined low pressure system Tue/Tue night, which is expected to split into two lobes. One tracks across the TN Valley and along the spine of the Appalachians during this timeframe. The other tracks along the Southeast Coast Tue and the up along the Mid Atlantic Coast Tue night before lingering well off the Delmarva Coast. Widespread rain will be common across the area Tue...tapering off from sw-ne after midnight Tue night. IFR conditions are more likely with the passage of this system. With the low lingering off the Delmarva and a progressive sw flow pattern aloft, periodic showers/MVFR conditions will be possible Wed and Thu. && .MARINE... SCA headlines remain in place for the northern Bay and northern coastal wtrs tonight with strong low pressure over SE Canada and high pressure building in from the west leading to strong NW flow over the local wtrs. Winds/waves/seas decrease into Sun morng as the high builds into the Mid Atlc, leading to benign marine conditions during the day. Next chance of SCA conditions will be Mon night/Tue with double-barrel low pressure affecting the area and E/NE flow increasing ahead of the low. Gale conditions then possible at least over the coastal waters and Bay Thu night through Fri night behind a strong cold front. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 1 AM EST Sunday for ANZ630-631-650- 652. && $$ SYNOPSIS...MPR NEAR TERM...BMD/MPR SHORT TERM...MPR LONG TERM...MAS AVIATION...JEF MARINE...MAS is the U.S. government's official web portal to all federal, state and local government web resources and services.