Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 220122 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 922 PM EDT Fri Apr 21 2017 .SYNOPSIS... A cold front crosses the area tonight then becomes nearly stationary across the Carolinas through the weekend. Low pressure will track eastward along the front Saturday through Sunday, then slowly drift offshore Monday through Tuesday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Latest MSAS has the cold front crossing the mts with a weak bndry located across the lwr MD ern shore, denoted by the BKN-OVC ST layer and onshore flow at OXB. Meanwhile, sct convection developing in warm sector across the fa. Cold front sags south across the region this evening to a position near or just south of the VA/NC border by 12Z. Weak wave riding east along this feature will likely serve to keep chc convection going through the night, highest pops south. High pressure nudging in from the north may cut off moisture supply along the eastern shore / nrn neck after 06Z thus lowest pops there. However, guidance shows areas of fog expanding west a a bit along the ern shore as winds remain onshore. Lows from the mid 50s north to low-mid 60s south. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... A wet period ahead with rainfall amounts between 1-3 inches through Monday, highest (2-3 inches) over the piedmont. Potent upr level low tracks slowly se and takes on a neg tilt by Sunday, spawning a sfc low along the sern coast which then is progged to get cut off from the main flow and drift ivof the Gulf Stream wall into the middle of next week. Models show both spacial and timing differences with the moisture fields but the jist of the forecast will be for waves of Atlantic moisture to rotate inland resulting in periodic shwrs (embedded tstrms especially over the sern zones). Lclly hvy downpours psbl starting late Sat. Meanwhile, high pressure to the ne results in a cool in-situ wedge over the piedmont along with areas of fog. Likely to categorical pops through the period except Sat morning with chc pops. One caveat will be the frontal position on Saturday. Thinking is that any severe threat stays across NC, but SPC has the MRGL risk for damaging winds/large hail as far north as VA Route 460. Will limit thunder chcs to extreme srn VA / NE NC Sat. Highs Sat from the upr 50s nwrn zones to the lwr 70s across interior ne NC. Lows Sat / Sun nights in the upr 40s to lwr 50s. Highs Sun in the upr 50s to mid 60s. Highs Mon upr 50s NW to near 70 SE. Hydro wise, no flood headlines expected attm despite the expected rainfall. Will probably have to wait until the first round or two of QPF falls then assess the situation. Do expect some healthy rises in local river by early next week, especially if the heavy rainfall falls over the headwaters. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Long term period will feature a trend towards drier and warmer conditions. For Mon night/Tue, mid-level cutoff low and associated sfc low continue to spin south of the area, allowing for moisture to stream in off the Atlantic. Bumped up PoPs to likely for most of the area Mon night and chance far NW, with models tending to push cutoffs lows offshore too quickly. Slightly lwr PoPs for Tue, with the best chance near the cst. Temps Tue slightly below normal...highs in the upr 60s most spots. Warming trend then commences for Wed as deep SWly flow develops across the eastern seaboard, lasting through the end of the week with temps reaching the 80s most areas Thu and Fri. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
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As of 01z...a frontal boundary extends from Maryland and northern Virginia to the Tennessee Valley. Scattered thunderstorms were over northern portions of the area affecting RIC and to affect other locations overnight. IFR stratus was present along the coast of the Lower Eastern Shore. AS the front moves to near the VA/NC border Saturday...IFR ceilings are expected to expand across much of the area (north of the front) by Saturday afternoon. OUTLOOK...Low pressure will move out of the Mid South to the Carolina coastal waters where it will linger into early next week. Unsettled conditions...widespread precipitation and degraded aviation conditions are expected through Monday. Conditions slowly improve but some rain may continue especially toward the coast. Currently a dry forecast is in place for Wednesday and Thursday.
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&& .MARINE... A cold front drops through the wtrs tonight. Expect a brief CAA surge behind the front Sat midday/aftn. Marginal SCA conditions are psbl over the Bay but held off on any headlines attm...confidence not high enough to issue a headline due to winds mainly expected to be around 15 kt, and a short duration of any SCA conditions. Several days of NE flow then as low pres develops over the SE states then slowly slides offshore. Still some uncertainty over when SCA conditions will commence, but they are likely for at least Sun through Tue, with 5-8 ft seas over the ocean and 3-4 ft waves over the Bay. Gale gusts are also psbl but expect mainly 15-25 kt winds with gusts up to 30 kt over the ocean. Improving marine conditions thereafter into midweek as the sfc low weakens and pushes off to the NE. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MPR NEAR TERM...MPR SHORT TERM...MPR LONG TERM...MAS AVIATION...LSA MARINE...MAS is the U.S. government's official web portal to all federal, state and local government web resources and services.