Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 120531 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 131 AM EDT Wed Aug 12 2020 .SYNOPSIS... A trough of low pressure east of the mountains, will increase the chance for showers and thunderstorms through Friday. A cold front pushes south across the area Friday night. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 810 PM EDT Tuesday... Early evening analysis shows coastal trough lingering across southeastern VA and south across the Carolina coastal plain. To the west, a diffuse piedmont trough persists over western VA up into central PA. Showers and T-Storms fired along the shear axis along the coast of SE VA/NE NC earlier this aftn/evening. Areas of locally heavy rainfall were observed, with portions of the eastern Hampton Roads area picking up between 2-4", including a report of a little more than 2.5" in 90 minutes time in Norfolk. Flash Flood Warnings in effect for this area have lapsed, but have maintained an areal flood warning with some lingering reports of minor flooding from spotters and on traffic cameras across the region. Farther inland, showers were fewer and farther between, but some localized heavy rainfall was noted along and west of the I-95 corridor, which has diminished with loss of heating. Expect that trend will continue into the overnight. Might see some isolated/lingering SHRAs over eastern VA and eastern shore along the trough axis. Otherwise, a partly cloudy and muggy night is expected w/ poss patchy FG/ST late into early Wed morning. Lows mainly 70-75F. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... As of 810 PM EDT Tuesday... Similar setup expected for Wed, as a sfc trough lingers back near the mountains and hi pres remains in the wrn Atlantic. The day may begin w/some patchy FG/ST...with some partial clearing into late morning. Expecting SCT SHRAs/tstms to develop from midday/early afternoon and continue through the evening hours. Expect the sfc trough to the west to be the focus for mid-late aftn and evening storms. Given PWs in the 1.75-2" range, along with expected low MBE velocities/steering flow for developing storms, and already diminished flash flood guidance from the multiple rounds of rains over the past week or so, there is some concern for a localized flash flood threat. Frequent lightning and gusty winds are also once again concerns aside from the heavy rainfall threat. Given the orientation of the front/sfc trough inland and majority of 12z/11 CAMs depicting storms/higher QPF more widespread and oriented just to our N-NW, not confident enough for any flood watches at this time. However, we will add some more wording to the Hazardous Weather Outlook for tomorrow over the piedmont and we`ll re-evaluate late tonight. Highs Wed in the u80s- around 90F...except m80s at the beaches. Trough aloft will become established INVOF OH/TN Valleys Thu-Fri. Tropical moisture will be increasing over the region leading to a high confidence for SHRAs/tstms. Given the recent overall wet wx pattern so far this month...flooding will likely become more of a concern due to PW`s well above normal. Heavy rain and poss slow movement to the SHRAs/tstms will contribute to that threat. Otw...mostly cloudy w/ highs Thu in the m80s then Fri in the l-m80s. Nighttime lows mainly 70-75F. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 120 PM EDT Tuesday... The extended period will remain unsettled. A slow moving weak upper level trough from the OH/TN Valleys (Fri night) will track across the FA this weekend into early next week. Meanwhile...hi pres will sit nearly stationary over the wrn Atlantic. Models suggest plentiful moisture through much of the period and there will likely be a sfc frontal boundary sitting over the local area (dissipating Mon-Tue). Expecting rather widespread coverage of SHRAs/tstms from Fri night through the weekend w/ locally heavy rain and poss flooding. A transition to more typical Summer conditions (and mainly diurnal pcpn) likely to occur Mon- Tue. Otw...VRB clouds-mostly cloudy through the period. Highs Sat/Sun mainly in the l-m80s...lows mainly in the u60s-l70s. Highs Mon-Tue in the mid-upr 80s. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... As of 130 AM EDT Wednesday... VFR conditions to start off the forecast period with some patchy pre-dawn IFR stratus/fog psbl btwn 09Z-12Z. Sct-bkn CU develop this aftrn as daytime heating combines with a sfc trof east of the mts. High res data suggests shwrs/tstms develop along this feature after 18Z. There is also the psblty of some isltd convection along lcl sea-breezes this aftrn, but activity is not expected to be as widespread as ystrdy was across sern VA. Added VCSH at RIC for now where PoPs are the highest. PoPs to low attm to add any pcpn to coastal TAF sites. Sct convection continues Wed eve before weakening after midnite. South winds aob 10 kts. Outlook: Ptchy late night stratus/BR possible Thurs morning. Shwrs/tstms become more widespread Thurs thru Sat as moisture increases along the sfc trof. && .MARINE... As of 245 PM EDT Tuesday... Quiet marine conditions continue this afternoon with high pressure centered well offshore and a weak lee trough in place across inland areas. Winds are generally southerly between 5-10 knots over the Ches Bay with winds averaging 10-15 knots offshore. Waves are around 1 foot with seas offshore aob 2 ft. A modest increase in SSE winds 10-15 knots this evening for the bay will subside back to 5-10 knots overnight. Expect a similar pattern to persist Wednesday into Thursday with some potential for mainly afternoon and evening thunderstorms. Weather becomes increasingly unsettled Friday into the weekend as a front and weak low pressure impact the region. A period of onshore/ENE winds is expected in the wake of the front with the potential for seas to build to 4-5 ft offshore from late Saturday into early next week. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MPR NEAR TERM...ALB/MAM SHORT TERM...ALB LONG TERM...ALB AVIATION...MPR MARINE...AJB is the U.S. government's official web portal to all federal, state and local government web resources and services.