Area Forecast Discussion
Issued by NWS Wakefield, VA
Issued by NWS Wakefield, VA
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383 FXUS61 KAKQ 200559 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 159 AM EDT Fri Sep 20 2024 .SYNOPSIS... High pressure will remain north of the region while low pressure remains well offshore. A backdoor cold front potentially drops back south across the region Saturday. High pressure builds north of the area this weekend into early next week leading to generally dry conditions. A cold front potentially approaches by the middle to later portions of next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 800 PM EDT Thursday... Key Messages: - Patchy fog possible tonight. Evening analysis shows sprawling low pressure offshore of the area. A trough over the eastern CONUS aloft will act to slowly deepen this low as it gradually drifts S over the next few days. Elsewhere, a weak stationary front is located S of the area, with a remnant upper low spinning over the eastern half of the area. Mix of cloud cover over the region with a decreasing trend this evening. Areas of low stratus are possible later tonight but much less coverage compared to the last few nights. Not expecting widespread dense fog at this time, but could see some patches of lower visibility toward sunrise. Low temps tonight generally in the low 60s with a few upper 50s possible in the typically cooler rural spots. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/... As of 300 PM EDT Thursday... Key Messages: - Drier weather returns Friday into Saturday. - Showers or isolated storms possible Saturday evening into Saturday night. - Cooler and mainly dry Sunday. Fairly pleasant Friday and Saturday with high pressure over New England extending down into the local area. Meanwhile, the previously referenced coastal low will linger well off the Mid Atlantic coast. Sunshine returns in earnest for Friday, with temperatures generally in the lower 80s (70s along the immediate coast). Low temperatures Friday night range from the upper 50s to lower 60s. There is less fog potential Friday night given lower dew points, but cannot rule it out (especially S). Mostly sunny skies continue into Saturday, with highs again in the upper 70s to lower 80s. Clouds increase late in the day and especially overnight as a shortwave on the wrn periphery of the upper trough drops through the area and a backdoor cold front-type features moves through at the sfc. These features could spark showers and isolated storms NW of the area later Saturday, possibly moving S into the area by the evening and overnight hours. While moisture profiles are not overly impressive, most guidance suggests something in the way of precip moving through and have MUCAPE actually increases some overnight as the cooler air aloft moves in, so there could be some rumbles of thunder with this activity. Lows Sat night around 60 F. Sunday will be cooler behind the front with afternoon highs in the mid-upper 70s. Will maintain a dry forecast for now, but there could be some lingering showers given the nearby upper trough. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 300 PM EDT Thursday... Key Messages: - Starting off cool Monday with dry conditions. - Gradually warming temps expected by the midweek, with low-end precipitation chances potentially returning. Offshore low pressure and associated upper low will depart well to our SE by early next week. This will bring rising mid/upper heights to the area, with a SW-NE oriented ridge forecasted to develop over the eastern CONUS. Thus, temperatures should gradually moderate back into the lower 80s by Tuesday and Wednesday. Monday, however, will be dry and feature slightly below normal highs in the mid 70s with gusty NE winds (especially along the coast) and partly-mostly cloudy skies. Precip chances potentially inch back up by Tuesday and especially Wednesday as a quick-moving shortwave ejects out of the Midwest, likely interacting with the next deep-layer trough coming out of the nrn US and Canada. 12z deterministic guidance shows several waves of precip associated with various smaller-scale disturbances. Timing these disturbances is difficult at this lead time and given associated spread across the ensemble guidance, will remain near or slightly above NBM PoPs during this period. This yields slight chc PoPs Tuesday aftn across the W, with 20-30% PoPs for most of the area Wednesday-Wednesday night with the parent cold front. Sky cover averages partly-mostly cloudy. Forecast overnight lows are in the upper 50s-lower 60s Sunday night, mid-upper 50s Monday night, and lower 60s Tuesday/Wednesday night. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... As of 200 AM EDT Friday... VFR prevails at the start of the 06z TAF period. Have seen some fog forming tonight across the region, but it has generally stayed away from the terminals so far. Do expect MVFR vsbys to impact some, if not all, the terminals later this morning. Fog will clear out an hour or two after sunrise, then VFR is expected the rest of the 06z period. Winds will be light overnight, then NE winds become gusty at the coast during the day (gusts 15-20kt). Outlook: Primarily VFR conditions expected through Sat afternoon. Scattered showers Sat evening may bring brief flight restrictions. && .MARINE... As of 955 PM EDT Thursday... Key Messages: - Small Craft Advisories have been issued for the coastal waters north of Parramore Island. - Additional Small Craft Advisories possible as early as tomorrow afternoon for seas, with SCAs likely this weekend into early next week. - Stronger NE winds return on Sunday, with persistent long period swells keeping seas elevated this weekend into the middle of next week. Went ahead and issued SCAs for the coastal waters N of Parramore Island as 5ft seas should return by late morning-midday Friday. No other changes to the going forecast. Previous Discussion as of 320 PM... Latest obs and buoy reports reflecting N/NE winds 10-15 kt over the waters this afternoon. Deepening ~1004 mb sfc low pressure continues meander just south of the southern New England coast, with the system stalled due to a blocking area of high pressure centered off the coast of Nova Scotia. Meanwhile, weak 1015+mb sfc high pressure builds NW of the waters. Resultant NNE winds continue this evening, backing to the NW as the surface high starts to build overhead. Buoy obs reflect seas subsiding largely as expected this afternoon. Seas were 3-4ft S of Cape Charles Light and ~4-5ft to the N. SCAs were lowered earlier today south of Parramore Island, and will be allowed to expire with the issuance of the afternoon package. Winds slowly diminish and back to the NW as the pressure gradient relaxes with high pressure building across the lower mid-Atlantic. will allow for further improvement in marine conditions. Expect seas to gradually improve as well with winds turning offshore and diminishing. Seas generally 3-4 ft, waves 1-2 ft. Previously referenced blocked low pressure south of Nantucket remains more or less in place on Fri. While N/NE winds will be sub- SCA at 10-15kt Fri-Sat, E-NE wind waves (8-10 second swell) from the offshore low arrives Fri morning into the afternoon, leading to seas increasing once again. Northern coastal waters will see 5-6ft seas by midday Friday, and by late Friday evening into Sat morning across southern coastal waters and the mouth of Chesapeake Bay. The pressure gradient over the waters also starts to tighten up again late Saturday and Sunday as the low dives SE. This should increase NE winds during this period, especially over coastal waters. The bay/rivers will likely need SCAs for winds ~20kt as early as late Sat night, but more likely on Sunday. Winds over coastal waters look to be 20-25kt. Building swell combined with elevated winds should allow seas to build to 6-8ft in the N and 5- 7ft S. While winds look to improve early next week, but energetic long period (E-NE, ~10 second) swells from the lingering low well offshore of New England will keep seas in 4-6 ft range over the coastal waters through at least the middle of next week. && .TIDES/COASTAL FLOODING... As of 910 PM EDT Thursday... Tide forecast is tracking well this evening. Went ahead and added areas around Tappahannock/West Point to the advisory based on observations/model forecasts. Otherwise, no major changes to the going forecast. Previous Discussion as of 320 PM EDT... Astronomical tides continue to increase with the approach of the coming full moon (Harvest moon) cycle. Astronomically higher astro tides, along with prolonged onshore flow will continue to produce tidal anomalies of 1-1.5 ft, resulting in nuisance to low-end minor tidal flooding across much of the area along the bay and tidal rivers through the end of the week. Have opted to extend the Coastal Flood Advisories given similar water levels near minor flood thresholds through Friday evening`s high tide cycle. While winds briefly diminish and turn offshore, the ebb tide will be short- lived, as winds turn back onshore over the weekend. Additional extension of advisories or perhaps Coastal Flood Warnings are likely to be needed over the weekend. Will hold coastal flood headlines at Friday night for now. Winds turning back onshore and gradually increasing Sat night and Sunday should bring building flood tide Saturday into Saturday night. With anomalies increasing once again, the potential for tide levels reaching moderate Coastal Flood Thresholds (best chances northern coastal zones and lower bay) does increase for tide cycles over the upcoming weekend. Coastal Flood Watches may be issued in upcoming forecast cycles for the weekend. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Coastal Flood Advisory until 6 AM EDT Saturday for MDZ021>023. Coastal Flood Advisory until 2 AM EDT Saturday for MDZ024-025. NC...Coastal Flood Advisory until 2 AM EDT Saturday for NCZ102. VA...Coastal Flood Advisory until 6 AM EDT Saturday for VAZ075-077. Coastal Flood Advisory until 2 AM EDT Saturday for VAZ076-078- 083>086-095>100-518-520>525. MARINE...Small Craft Advisory from 10 AM this morning to 6 AM EDT Sunday for ANZ650-652. && $$ SYNOPSIS...AJB/SW NEAR TERM...RHR/SW SHORT TERM...AJB/SW LONG TERM...SW AVIATION...AM MARINE...ERI/MAM TIDES/COASTAL FLOODING...