Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 050134 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 834 PM EST Sun Dec 4 2016 .SYNOPSIS... Low pressure passes south of the region late tonight and Monday. A complex area of low pressure crosses the region Tuesday. A strong cold front crosses the area Thursday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 830 pm update...Afternoon forecast in good shape. Have tweaked POPs/WX to account for current trends, which show precip spreading eastward a little faster than earlier thought. Also tweaked hourly temps overnight some based upon current observations and hi-res model trends. Biggest change was to back off on the amount of fog expected. Best chance for fog development appears to be SE half of CWA, and that appears to be patchy and not widespread. Warm front remains far enough that widespread fog should not occur. Late afternoon discussion...Sfc high will slide off the NC coast this evening. Current sfc obs to the ssw are showing light rain beginning to fall out of a 6-8K ft cloud deck so will carry chc/likely pops mainly south of I64 through 00Z to account for this trend. High res data continues to show a rapid increase in moisture SW-NE across the region between 00Z-04Z. Given the current temp/dp temp scheme, it is not out of the question to see a few sleet pellets mix in with the rain at the beginning across northern most zones this evening before the column wet bulbs out above freezing. However, this to be rather insignificant and has been left out of the grids. Weak low pressure tracks east along the trof later tonite with the best lift progged between 03Z-10Z. Strongest lift noted across the south where the highest QPF will be (1/2 to 3/4 inch with 1/4 to 1/3 inch across the north). Thus, confidence high enough to max out pops (90-100%). Expect areas of fog given the stratiformed pcpn. Lows in the mid-upr 30s northern most zones to the lwr 40s across the se. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Models take the sfc low off the Mid Atlantic coast Monday morning with high pressure building south from the Ohio valley. Thus, pcpn quickly ends w-e between 12-17Z. Will carry pops across the east through noon then dry as the high quickly dries out the column. NAM more aggressive than the GFS in decreasing the cloud coverage, but will lean toward clouds giving way to pt sunny skies across the north during the aftrn. Temps respond to the sunshine given no real CAA seen. Highs in the mid-upr 50s. Models are now even slower in returning the moisture across the area Monday night as the high slowly drifts ene across PA into New England. Won`t get to fancy here given how the models generally underestimate just how fast pcpn breaks out in and overrunning scenario. Clouds thicken in the evening with rain overspreading the fa SW-NE after midnight. Lows upr 30s north to upr 40s SE. Tuesday remains a challenge as low pressure rides NE along the mts with a scendary low pressure tracking NE along the Carolina coast. Coupious amounts of both GOM/Atlantic moisture become entrained and track across the region. Models consistant in tracking the triple point low across the northern outer banks keeping the center ivof eastern Albemarle sound. This track will likely keep pcpn type mainly stratiformed across the fa but may become convective across the extreme sern zones for a few hours during the afternoon. Temp forecast tricky due to a strong insitu-wedge holding readings arnd 40 most of the day across the nwrn most zones (LKU) ranging to the low-mid 60s ivof the northern outer banks (ONX). Forcing strong enough for a several hour period of mdt to psbly heavy rainfall with widespread rainfall amounts between 1/2 to 1 inch. Pcpn slowly ends SW-NE Tuesday night as the best lift moves NE. Lows 35-40 west, 40s east. The low slowly pulls away from the region Wednesday with deep layered SW flow behind it. Decreasing clouds in the morning bcmg mstly sunny in the aftrn. Highs in the mid-upr 50s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Long term period starts off Wed night with dry weather as the aforementioned low pressure system pushes farther offshore and high pressure briefly builds into the Mid Atlc. Low temps in the mid 30s to lwr 40s under a partly/mostly cloudy sky. A strong cold front crosses the area on Thu. ECWMF continues to be slower than the GFS with the fropa, which would delay the precip until late in the day/eveng hours. Pcpn amounts are expected to be lower than with the system Tue. There is also a chance that some of the light pcpn could mix with or change to snow showers late Thu. Hi temps Thu in the low/mid 50s most areas. Dry weather thereafter for Fri into the weekend as sfc high pressure builds in from the west. Cold nighttime temps expected Thu night through Sat night, with lows in the low/mid 20s most locations. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... A low pressure system located near the Gulf Coast will continue to lift northeast through Sunday night. Rain will continue to overspread the area from the southwest through the first half of the night. Low pressure moves off the coast early Monday morning leading to VFR conditions returning. VFR conditions at all terminals as of 00Z, but rain is just on our doorstep. Showers should impact RIC and ECG first and will continue to spread across the area from the Southwest. Ceilings will continue to fall through the evening, am anticipating a period of IFR ceilings at all TAF sites closer to sunrise. All rain should clear the area by 12Z and VFR conditions will return to the area by Monday afternoon. Outlook: Rain moves out early Monday, with VFR conditions returning. High clouds once again thicken and lower through the afternoon on Monday ahead of the next system. Steady rain to overspread the area from southwest to northeast late in the evening and overnight on Monday. High confidence of MVFR to IFR ceilings and visibilities (and potentially LIFR conditions) during this period. Rain continues through the day on Tuesday before tapering off Tuesday night. Widespread MVFR/IFR returns Tuesday night, with conditions recovering to VFR behind the system on Wednesday. && .MARINE... Latest sfc analysis shows high pressure sliding off the Mid Atlc coast with disorganized low pressure near the Gulf coast. Weak low pressure will pass through the Carolinas tonight and allow for increasing northerly winds behind the low Mon, though still below sca criteria. A much stronger low pressure system affects the area Tue, with east winds/waves/seas increasing ahead of the low. Will hold off with any headlines attm with this as it`s fourth period and still some uncertainty over the timing of the increase of winds. Winds then shift to the W/NW Tue night/Wed. A strong cold front then crosses the region by late Thu, with gale conditions possible over at least the coastal waters and Bay Thu night through Fri night behind the front. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MPR NEAR TERM...MPR/WRS SHORT TERM...MPR LONG TERM...MAS AVIATION...AJB/JEF MARINE...MAS

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