Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 190143 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 943 PM EDT Thu Apr 18 2019 .SYNOPSIS... A warm front will be well north of the area tonight. A strong cold front arrives late Friday. An upper level low will be slow to lift northeast over the weekend. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... As of 400 PM EDT Thursday... Low pressure is moving across the MS/AL this evening and a high pressure is located off the Mid-Atlantic coast. The tightening pressure gradient is producing decent southerly winds. Overnight winds will remain S 10-15 kt with gust near 20 kt, and up to 25 kt near the coast. Low clouds will move in after 06z tonight and thicken overnight. A few showers will develop and move north along and west of I95. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... As of 420 PM EDT Thursday... Upper trough sharpens significantly W of the mountains Fri and eventually closes off as it pushes into the TN valley by Fri evening. The attendant sfc low pressure areas lift ENE into SE OH and near the TN/NC border, with the trailing cold front entering the mountains Fri evening. That front will be slow to push E to the coast Fri night, due to deep layered S flow sfc- aloft. Models continue to hone in on a narrow axis of deep layered moisture. This influx of deep layer gulf moisture will once again support PW values of 1.5-1.7" (or +2 to +3 Std Dev) over the local area late Fri into Fri night, and cause a spike in sfc dew points. Expect periods of showers/tstms with the potential for some locally heavy rainfall late Fri aftn into Fri night. QPF of 1-1.5" with the potential for locally higher totals. No Flood Watches have been issued at this time, but will need to possibly issue one for some areas, esply along and east of I95. Also, SPC has a slight risk for NE portions of the FA Fri/Fri night, and an enhanced risk over cntrl/srn/se portions of the FA. Additionally, most of the FA is in a slight risk for excessive rainfall. Highs on Fri will range thru the 70s, with upper 60s right at the immediate coast. Regarding the convective threat, there remains some question as to how much instability can be generated given the forecasted cloud coverage, but that may be overtaken to some degree by the favorable dynamics the system will have. Strong forcing for ascent will exist with wind fields aloft easily able to support damaging winds in any bowing line segments. Additionally, potential slight backing of near sfc/low level winds acrs SE VA-NE NC will need to be watched very closely Fri aftn/evening, esply if any clearing can be realized. Aside from anticipated possible hydro issues, timing for any strong/svr storms appear to be late aftn/evening (4p-8p) west of I95, between 8p-midnight along and east of I95, and 12a-3a along the immediate coast. Rainfall/convective wind potential will continue to be highlighted in the HWO, and will continue to mention for gusts even outside of convection, due to tightening pressure gradient Fri morning into Fri aftn. Appears our area may approach wind advisory criteria ahead of storms Fri morning/aftn along the coast, and will need to monitor that in future packages. The cold front pushes offshore late Fri night/early Sat morning. Going mainly dry the remainder of Sat into Sat night acrs the region, as front/pcpn will be pushing out to sea and upper low and associated moisture remains WNW of CWA. So, generally partly sunny on Sat with highs ranging fm the mid 60s to lower 70s. Upper low/associated moisture will then move into and acrs the area late Sat night thru Sun. Partly cloudy to cloudy with a slgt chc to sml chc of showers late Sat night and Sun. Lows Sat night in the upper 40s to lower 50s. Highs on Sun in the 60s. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 400 PM EDT Thursday... Upper-level low will be over the area during the day on Sunday and into early Monday morning. 20- 40 Pops were put in, with the greatest chance in the northern parts of the area. There is a chance of thunder as the cold pool core moves over the area, but no thunder was added to the forecast at this time. As the upper-level low moves off to the NE, a SW flow will begin ahead of a front that will move south out of the Great Lakes. With the upper-level flow out of the west early next week, the front will stall and a chance of showers will be around for Tue-Thu. However, models are in disagreements on were the boundary will stall, therefore only 20-30 Pops were put in through Friday. Temperatures will be cool on Sunday with the upper-level low over the area. Highs will be in the 60s and lows in the 40s inland to mid 50s along the coast and eastern shore. 80s will return by Tuesday with a SW wind. Temps will remain mild for the remainder of the week as a front stalls across the area, with highs ranging from the 60s to near 70. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... As of 830 PM EDT Thursday... VFR conditions will last through 06z Friday before moisture begins to advect into the area as a low pressure systems approaches. BKN CIGs between 020 and 030 ft will move in between 06z and 09z from S to N. Scattered showers and an isolated thunderstorm will move across the western part of the area, mainly affecting KRIC, during the mid morning. Vis may be reduced to IFR during a heavier shower/Tstorm. Low CIGs may become more SCT during the day on Friday ahead of the main line of thunderstorms, therefore most site should return to VFR during the early afternoon. KSBY and KRIC may return to MVFR before the end of the 00 TAF period. Winds this evening have already increased out of the S between 10 and 15 kt with gust near 20 kt. Winds will decrease slight overnight before increasing during the day. Winds on Friday will be S around 20 kt with gust exceeding 30 kt, especially at KORF/KPHF/KSBY. Flight restriction will likely return as the line of the heavy thunderstorms moved through the area after 00z Sat. After, the upper-level trough will move over the mid-Atlantic and bring showers and possible more flight restrictions. && .MARINE... As of 400 PM EDT Thursday... Will start the SCA headlines with this package (except the rivers) as SCA level winds will likely develop within the next 12 hrs. However, models are showing that the Ches Bay winds may actually slacken a bit for a few hrs after midnight for a few hrs before increasing again towards sunrise. Tightening pres gradient Fri results in slowly increasing south winds throughout the day, but remain below gale force. Will cap gusts at 30 kts on Fri for now. Tricky forecast Fri nite with both synoptic and convective gusts expected. Models show a quick increase in synoptic winds Fri eve (tapping some of the low lvl jet). This ahead of a fairly strong line of convective progged to move across the waters through the night. Wind probs show fairly high confidence for 35+ kts of wind across the srn cstl waters and Currituck Sound, thus a gale warning will replace the current gale watch where gusts up to 40 kts possible. Props a bit lower farther north and west, so have elected to hoist a gale watch for both the nrn coastal waters and the Ches bay Fri night for gusts to 35 kts. Data also indicates this to no more than a 4-6 hr prd of gales with winds diminishing behind the line of convection. Slowly improving conditions are expected over the weekend as an upper level low is slow to exit to the NE. && .TIDES/COASTAL FLOODING... As of 400 PM EDT Thursday... Latest guid not as bullish with the threast for mdt flooding than previous data suggested, so no coastal flood watches at this time. However, Bishops Head is forecasted to just reach minor flooding with tonights high tide cycle and go above minor flooding with Friday nights high tide. Thus, will issue a coastal flood statement for BH tonite as rising tidal departures to 1 to 1.5 FT above MLLW. Otw, several other stages will likely reach or exceed action stages due to the strong srly winds. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 8 AM to 8 PM EDT Friday for ANZ633- 635>638. Gale Watch from Friday evening through late Friday night for ANZ630>632-634. Small Craft Advisory until 8 PM EDT Friday for ANZ630>632-634- 650-652-654-656-658. Gale Warning from 8 PM Friday to 4 AM EDT Saturday for ANZ633. Gale Warning from 8 PM Friday to 5 AM EDT Saturday for ANZ654- 656-658. Gale Watch from Friday evening through late Friday night for ANZ650-652. && $$ SYNOPSIS...TMG NEAR TERM...TMG/CP SHORT TERM...ALB/TMG LONG TERM...CP AVIATION...TMG/CP MARINE...MPR TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.