Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 151020 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 520 AM EST Mon Jan 15 2018 .SYNOPSIS... Arctic high pressure will extend south into the region today and tonight. A cold front crosses the area Wednesday morning with low pressure moving northeast along the coast Wednesday afternoon and night. A second surge of arctic air pushes across the area Wednesday night and Thursday before temperatures moderate into next weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Quick update to account for the snow shwrs developing along the sern beaches this morning. PVS DSCN: Latest MSAS has the arctic high centered over ern Canada and extending south along the ern seaboard. Meanwhile, a sfc trof was located across the applach mts with anthr trof offshore. Todays forecast a challenge wrt cloud coverage and temps as low level moisture in the form of a BKN-OVC SC deck btwn 2-4K FT continues to spread onshore from the offshore trof. Models also dvlp a weak low then track it NNE along the Gulf stream wall then into the Vacapes later today and tonite. This feature will likely keep it cloudy along and east of the I95 corridor (OVC at the coast) with even a few fluries psbl across the ern shore. At the same time, high level clouds assctd with the trof across the mts will keep it pt sunny across the Piedmont. Highs in the low-mid 30s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... Coastal wave lifts out with weak high pressure over the area tonite. Models still show enough moisture to keep skies mstly cldy east with pt cldy skies west. Cold with lows in the 20s. Anthr weak low progged to lift north just off the coast Tue with a cold front apprchg from the west. AKQ fa in btwn these features as weak high drifts toward the Carolina coast. Although weak, the return flow results in a short lived warmup across the region as temps rise into the low-mid 40s. Still a lot of uncertainty for the well advertised mid week event with no real clear model to choose from. The one thing I have done was to discount the 15/00Z NAM solution of little to no QPF with the front. The GFS continues to be quicker with less QPF assctd with the upr level systm that tracks across the Piedmont. It appears to keep the system pos tilted and ends pcpn Wed aftrn. The ECMWF/Canadian cont trying to go neg tilted for a while thus slower solns with more QPF assctd with the upr lvl systm which lasts into Wed nite along the coast. P-type not a big challenge as thermal profiles suggest mainly snow except for a rain/snow mix at times Wed ivof the Albemarle Sound. The challenge as always, conts to be snowfall amts. Trying to keep continuity, went with a GFS/ECMWF blend for now. Upshot will be for snow to overspread the Piedmont after midnite Tues nite then spread east Wed morning. Enough confidence to increase to likely pops wrn most zones, chc pops farther east. Lows in the 20s to arnd 30 SE. Likely pops Wed across the Piedmont as the upr lvl moisture tracks SE. Chc pops elsewhere for now although if the EURO/Canadian verify, higher pops would need to be extended into the aftrn. Highs 30-35. Pcpn exits off the coast Wed evening with decreasing clouds after midnite. Cold as yet anthr shot of arctic air overspreads the area so would think any snow or water from the storm freezes solid. Lows 15-20 except lwr 20s sern coastal zones. QPF of .10 or less east of the I95 corridor, .10 to .25 across the Piedmont. Expect varying SLR`s across the fa as well ranging from arnd 10:1 across the se to as much as 15:1 over the Piedmont. This translates mainly to an advsry level event with amts ranging from inch or less east of I95, 1-2 inches along the I95 corridor, 2-3 with up to 4 inches across the Piedmont (given the higher SLRs). && .LONG TERM /THURSDAY THROUGH SUNDAY/... High pressure builds into and over the region Thurs and Fri. The cntr of the high will set up south of the area or off the SE coast for thru Sun. The high will provide dry wx for Thu thru Sun, with moderating temps thru the period. Highs will be in the mid to upper 30s Thu, in the 40s to near 50 Fri, in the upper 40s to mid 50s Sat, and in the mid 50s to lower 60s Sun. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... MVFR SC btwn 2-4K ft continue to spread onshore this morning and are forecasted to move as far west as the I95 corridor after sunrise. Thus, VFR conditions to start off the forecast period will quickly lower to MVFR along coastal sites thru the pre dawn hrs. Per Tsctns, went with a few hour tempo group erly for the transition then basically socked in all coastal TAF sites with OVC MVFR conditions (203K FT) through 00Z Tue. NAM/GFS hinting at some IFR CIGS by 00Z at ECG but held off on going that low for now. Also, a few flurries are psbl across the ern shore later today but these should not be an aviation hazard. RIC stays VFR although BKN SC arnd 5K FT will flurt with that area today. NNE wind remain gusty btwn 10-20 kt at ORF/ECG with winds generally aob 10 kts. Outlook: Unsettled into midweek, as potent upper trough brings thickening/lowering clouds by late Tue, with some flight restrictions possible into Wed. Some light wintry pcpn likely Tue night and Wed as clipper and associated cold front cross the region...with clearing late Wed. Predominate VFR then likely Thu/Fri as the trough ejects NE offshore. && .MARINE... 1048mb high pressure is centered over QB early this morning and is ridging to the SSW along the piedmont. Meanwhile, weak low pressure is situated well off the Southeast coast. This combination is resulting in a N wind of 15-20kt across the far nrn portion of the area and the lower James, and up to 20-25kt with gusts ~30kt from the lower Bay through the srn ocean zones and Currituck Sound (10-15kt for the Rappahannock/York/Upper James). Seas range from 4- 6ft N, to 6-8ft off the nrn Outer Banks. The wind is expected to gradually diminish later this morning through the aftn and then by tonight remaining northerly with speeds dropping to 8-12kt. SCAs for the Bay/Sound have been extending to 21z, the ocean to 15z Tuesday for seas remaining 4-6ft tonight into early Tuesday, and the lower James has been added to the SCA through 15z today. The wind should diminish by Tuesday as a weak surface ridge settles near the coast. A surface cold front crosses the coast Tuesday night, with strong CAA lagging behind until the upper trough arrives Wednesday night into early Thursday. The wind is expected to become N 10-20kt Wednesday, and then NW 15-25kt Wednesday night into early Thursday. SCA conditions are likely for wind and seas. High pressure settles over the area by Thursday aftn and Thursday night, and then slides off the Southeast coast Friday. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 4 PM EST this afternoon for ANZ630>634. Small Craft Advisory until 10 AM EST this morning for ANZ638. Small Craft Advisory until 10 AM EST Tuesday for ANZ650-652- 654-656-658. && $$ SYNOPSIS...MPR NEAR TERM...MPR SHORT TERM...MPR LONG TERM...TMG AVIATION...MPR MARINE...AJZ

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