Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 232111 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 411 PM EST Tue Jan 23 2018 .SYNOPSIS... A cold front moves off the coast this evening. High pressure becomes centered over the south central states Wednesday and builds east into the local area for Thursday and Friday. The highs slides off the coast for the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Latest analysis places center of main sfc low pressure across the St Lawrence Valley, with a secondary sfc trough and the associated sfc cold front now pushing through the CWA and approaching the coast. Showers have genly ended except near the coast/eastern shore. Winds remain gusty from the WSW most places with deep mixing and very warm/near record high temperatures this aftn (into the upper 60s/lower 70s over most locations). Had an SPS in effect earlier for wind gusts to ~40mph, but have allowed that to expire as the winds are now slowly diminishing and now are mainly gusting to 35 mph or lower. The winds will continue to further diminish over the next few hrs. See record highs noted in CLIMATE section below. There are some areas of marine fog over the northern coastal waters and this will persist through 22-00Z before the front scours things out and conditions improve. Otherwise for tonight, skies will be mostly clear with winds shifting to the WNW. Temperatures remain mild this evening then fall off overnight with lows Wed morning ranging from the lower 40s SE coast to the lower-mid 30s along/west of I-95 and across the eastern shore. Dry cooler for Wed with sfc high pressure centered over the south central CONUS, building east to the Gulf coast region by aftn. Sunny in the morning, then some increase in clouds in the aftn (though still partly-mostly sunny). Low level thicknesses and 850mb temps support highs from the upper 40s/near 50 F on the ern shore and mainly lower- mid 50s elsewhere. This matches up well with MET/ECS guidance (MAV appears too warm). && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... GFS/NAM continue to depict a fast moving upper trough swinging through the region Wed night, and this will bring a few hrs of partly/mostly cloudy skies, with clearing after midnight. Lows in the upper 20s-low 30s. Mainly sunny and a few degrees cooler Thu w/ highs from the low 40s NE to around 50 F south central VA/interior NE NC. Lighter winds/clear Thu night as the sfc high becomes centered over the local area and will go on the cold side of guidance with lows mainly in the 20s. Sunny, and turning warmer Fri with highs upper 40s/around 50F NE to the mid 50s W of Ches Bay. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Overall pattern continues to show the long term period beginning with a shortwave ridge building eastward from the Mississippi Valley into the Southeastern US and Mid-Atlantic states on Friday into Saturday. This is followed by a full latitude trough that moves in on Sunday into Monday. But today, the timing between the models and strength of the cold front crossing the area is different with the 12z GFS slower and weaker while the 12z ECMWF is slower, stronger and would provide more rain for the region. The ECMWF right now has better run to run continuity than the GFS as the 6z GFS was slower and wetter than the 12z run. So for now have leaned a little more toward the slower ECMWF for that part of the forecast. On Thursday night through Friday, high pressure will be in control of the regions weather with the high overhead expect to see a very cool night with good radiational cooling, lows in the m20s-l30s. Temperatures will begin to warm again on Friday as warm advection begins with sw flow, expect highs in the u40s to u50s. Mex guidance is a bit warmer and began to trend that direction raising highs a few degrees above the other guidance. The SW flow continues on Fri night with more dry weather and maybe a few more clouds. Temperatures in the mid to upper 30s are expected. For Saturday through Sunday night, this is where the most interesting portion of the extended lies as the quicker GFS has the moisture and front approaching the area by late Sat afternoon, which is about 6 to 12 hours faster than the 6z GFS or ECMWF. At this range, did raise pops a touch, but kept the forecast dry on Sat with temperatures getting back into the U50s to l60s. But beginning Sat night did start to raise pops up to high chance values. Some guidance suggest pops in the likely range are possible now, but with timing issues and also the questionable forcing have capped pops at 50% from Late Sat night through Sunday with a slow clearing of the pops in Sunday evening. Sunday looks like the most probably period for rain and the ECMWF would indicate a beneficial rain, which would be good for the drought areas, but at this range models have been showing these types of events for the last few weeks, but the plentiful rain has been materializing. Have kept temps mild on Sat night and Sunday with lows in the 40s and highs still in the 60s. The front should clear the area Sunday night with NW and high pressure building in on Monday. The strength of the developing upper trough will determine how strong the low over New England gets Sunday night and this will impact temps on Monday. The ECMWF would suggest temperatures cooler than the currently forecast in the upper 40s to mid 50s on Monday. But for now will not bit completely on the ECMWF. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... TAF Sites are now VFR, though some MVFR/IFR CIGS/VSBYS along the coastal eastern shore through 22-00Z. Gusty SW winds shifting to the WNW between 21-00Z. Additional showers possible through 20Z inland and 23Z along the coast with brief MVFR/IFR conditions possible. Clearing/dry tonight. Sfc high pressure builds into the local area from the SW through Thu. && .MARINE... Late this aftn, a cold front was pushing to just west of the Ches Bay. Southwest or west winds of 15 to 20 kt with gusts to 25 kt were still occurring right in advance of the front, and SCAs will continue until 7 pm over the Rivers/Ches Bay and Currituck Snd, and until 10 pm or midnight for the coastal waters. Front will move out to sea during this evening/early tonight, with winds becoming west 5-15 kt. West winds 5-15 kt on Wed, will become northwest Wed night. There is another surge of colder air late Wed night into Thu aftn, which will result in NW winds 10-20 kt with higher gusts possible. Waves and seas may increase by a foot to 2 to 4 ft with this surge Thu. Conditions improve by Fri, as high pressure builds into and over the area. && .CLIMATE... Record high temperatures today. Tuesday RIC 76/1974 ORF 76/1999 SBY 73/1999 ECG 76/1937 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ630>638. Small Craft Advisory until midnight EST tonight for ANZ650-652- 654. Small Craft Advisory until 10 PM EST this evening for ANZ656- 658. Dense Fog Advisory until 7 PM EST this evening for ANZ650-652. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...ALB/LKB LONG TERM...ESS AVIATION...LKB MARINE...TMG CLIMATE...AKQ is the U.S. government's official web portal to all federal, state and local government web resources and services.