Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 210117 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 817 PM EST Fri Jan 20 2017 .SYNOPSIS... A frontal boundary will weaken as it stalls across the Mid Atlantic region tonight. Low pressure over the nations mid section Saturday and Sunday will intensify as it slowly tracks east across the Mid Atlantic region Sunday night and Monday. The intense low will move off the New England coast Tuesday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Latest MSAS has high pressure off the New England coast with a warm front still west of the mts. 12Z data now showing this boundary weakening/washing out across the region tonight leaving the fa in a saturated airmass as weak high pressure builds aloft. Tsctns showing abundant low level moisture but little if any support for measurable pcpn after 00Z. Thus, expect any light rain to end early with patchy fog/drizzle developing across the area. Bufkit showing a combo of stratus and fog so have trended the grids towards that solution. Lows upr 30s-lwr 40s. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Not much change in synoptic features seen on Saturday as the fa remains in between systems with weak high pressure overhead. Thus, expect patchy fog/drizzle to continue into the morning hours with a slow improvement (albeit remaining mstly cldy to cldy into the mid day and afternoon hours). Moisture begins to increase from the s/sw late. Will carry low chc shwrs across swrn most zones after 21Z. Mild despite no sun. H85 temps support highs from the mid- upr 50s Delmarva to upr 50s-lwr 60s west of the Ches Bay. Challenging forecast thereafter as model differences appear Saturday night and continue through Monday. Given how dry the 12Z GFS is compared to the previous run (basically dry through 12Z Sun), have trended this forecast more in line toward a NAM/ECMWF blend where shortwave energy moves NE Saturday night resulting in chc to likely pops overspreading the fa. Data shows little instability but a decent amount of Atlantic moisture getting entrained from the SE. Thus, could see some mdt rainfall rates at times across the south. The high to the north keeps nern zones with chc pops. Lows from the mid 40s Delmarva to lwr 50s srn most zones. Next shortwave tracks across the fa Sunday with categorical pops as a good amount of lift and low level moisture is noted. Increasing PW`s will result in mdt to locally heavy rainfall. Warm frontal boundary progged to drift north to near the NC - VA border so will keep slght chc thunder across southern half of fa during the afternoon. Warm with highs in the upr 50s to lwr 60s north to mid-upr 60s south. Models continue to have trouble with the stacked upr level low progged to slowly cross the region late Sunday night and Monday. Categorical pops for shwrs Sunday night. Lows upr 40s - mid 50s. At some point in time, a triple point low is forecasted to cross Virginia. Current timing is Monday which will continue to produce widespread shwrs across the north with a dry slot potentially cutting off pcpn across parts of the area Monday afternoon. However, enough instab noted to keep thunder mentioned across the SE in the warm sector. Highs mid 50s to lwr 60s. Qpf through Monday should average one to two inches with locally higher amounts possible. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Upper low pressure lifts northeastward away from the region Monday night and Tuesday, with precipitation chances winding down by Tuesday morning. High pressure is expected to return Tuesday night into Wednesday. A cold front associated with an upper low lifting over eastern Canada is progged to push across the region late Wednesday night and Thursday. Will hold onto slight chc to low chc pops (20-30%) during this time. High pressure returns again next Friday with temperatures falling back below normal for this first time in awhile. Highs Tuesday mostly in the 50s. Highs Wednesday from the mid 50s Eastern Shore to the low 60s inland. Thursday`s highs back in the 50s, then cooling into the 40s next Friday. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
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Weak low pressure near the North Carolina coast will move northeast. Weak high pressure will prevail Saturday. Low pressure develops over the southern Great Plains Saturday and moves east and northeast to Virginia Monday. As of 00Z...Rain moved off the coast early Friday evening. IFR conditions are present at RIC and has been intermittent over southeast portions. With near calm winds...expect widespread IFR and LIFR ceilings and visbilties overnight. IFR will be slow to improve on Saturday with the greatest improvement occurring along the coast. RIC may see IFR persist throughout the day. OUTLOOK...IFR conditions become widespread once again Saturday night. As rain develops Sunday...IFR will be slow to improve if at all. Periods of rain Sunday night and Monday will be accompanied by IFR conditions. As low pressure moves off to the northeast...dry weather and a clearing sky is indicated for Tuesday and Wednesday.
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&& .MARINE... Winds remain E aob 10kt this afternoon into this evening before becoming NE and N tonight. Long period swell will keep seas between 3-4 ft into this evening. Winds become E then SE Saturday with speeds remaining 10kt or less. Seas 2-3ft; waves 1-2ft. Winds become SE 10-15 kt on Sunday as the first of two low pressure systems impact the region. Seas build to 3-4 ft, except up to 5 ft southern outer waters. The second low pressure system begins to impact the region Sunday night with winds remaining 10-15 kt, except increasing to 20-25 kt north of Chincoteague early Monday morning. A brief period of gale gusts is possible early Monday morning across the northern coastal waters. However, models continue to push the highest wind threat further north into DE/NJ. Seas 3-5 ft across the south Sunday night, building to 5-8 ft off Ocean City by early Monday morning. Low pressure lifts north through the interior Mid- Atlantic during Monday before lifting north of the area on Tuesday. Winds will vary from SE to SW 10-15 across much of the marine area Monday, while generally remaining E across the northern coastal waters and diminishing through the day from 20-25 kt down to 15 kt. Seas build to 6-10 ft north while remaining 3-5 ft south. Winds become NW all waters on Tuesday with SCA conditions probable, especially for the coastal waters. Seas 4-8 ft. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MPR NEAR TERM...MPR SHORT TERM...MPR LONG TERM...JDM AVIATION...LSA MARINE...JDM is the U.S. government's official web portal to all federal, state and local government web resources and services.