Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 171601 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 1101 AM EST Wed Jan 17 2018 .SYNOPSIS... A strong cold front has pushed just off the coast late this morning. Weak low pressure will track northeast just off the Mid Atlantic coast this afternoon and tonight. A second surge of arctic air pushes across the area tonight into Thursday before temperatures moderate into next weekend and drier conditions return. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Late this morning, cold frontal boundary has moved just offshore, with latest radar indicating the leading edge of snow extending fm the VA nrn neck SW to near AKQ, then contined SW into cntrl NC. So far, we have received snow reports ranging fm near 1 inch over nrn portions of the area to near 4 inches over scntrl VA counties. The latest HRRR/RAP models indicate this area of snow will gradually shift to the ESE this aftn into this evening, as the upper level shortwv energy/vorticity advection and associated vertical motion, lifts fm ern GA and SC northeast twd the Mid Atlc coast. It still looks like higher snow amts will occur over scntrl VA into interior NE NC and SE VA. Believe portions of coastal NE NC will have to be monitored closely this evening into tonight for possible higher amts, as more energy and lift gets transferred into this area. Otherwise, do not plan any adjustments on Advisory or Warning ending times, but depending on trends, may have to extend warning ending times in the Scntrl VA zns. Temps will be falling into the mid 20s to lower 30s later this aftn into early this evening. Previous discussion: 17/00z suite once again have trended slightly slower and upward with QPF as the system becomes closed placing a narrow zone from central NC to south central VA into optimal placement for deformation and f-gen banding within a deep upper level diffluent zone, with negative Sat EPV values suggesting some convective processes and strong UVV. Model consensus supports QPF of 0.35-0.5" across the Piedmont and s-central VA and Northampton NC, bordered by ~0.1 to 0.2" from central VA to E VA and NE NC, with 0.1" or less over the lower eastern shore. Expect some variability in SLRs, but generally ratios of 12-15:1 are expected during the highest PoPs, which supports 5-7" of snow across the SW Piedmont in the aforementioned ideal location, bordered by 3-5" from the FVX area to s-central VA and Northampton NC, with 1-3" for the I-95 corridor of central VA sewd to Hampton Roads. Coastal NE NC will need to be monitored for this evening as deepening low pressure off the coast could result in f-gen banding and the potential for warning criteria for coastal NE NC. The Winter Storm Warning has been expanded for the SW Piedmont and S-central VA. Have opted to maintain a high-end advisory for Hampton Roads, with the remaining advisories remaining as is. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... The sky will clear quickly tonight as the well-advertised quick shot of arctic air surges into the region. Shallow mixing is expected to persist overnight, which should inhibit temperatures from plummeting too far. Still cold nonetheless with lows in the teens inland to the upper teens/low 20s for coastal SE VA/NE NC. Mid-level WAA resumes rather quickly Thursday with 850mb temperatures of -2 to -4C at 12z warming to +4-6C by 21z. A cold start to the day, limited mixing, and mid-level WAA should result in rather stable lapse rates and surface high temperatures Thursday should only reach the mid 30s to low 40s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Pattern change looks to occur during the medium range period with a significant warmup expected through the upcoming weekend/early next week. It will still be on the cold side early Fri morning with sfc high pressure centered across the deep south, and one last upper trough moving ESE to the New England coast. Latest GFS/ECMWF/CMC depict the upper trough moving well off the New England coast Fri with a broad upper level ridge building over the eastern CONUS Fri aftn through the weekend. Expect continued dry conditions with warming temperatures, highs in the upper 40s/lower 50s Fri, rising well into the 50s (possibly near 60F) Sat, and into the upper 50s to lower 60s for Sun. Lows Fri night/Sat am in the mid 20s to mid 30s, and Sat night/Sun am in the 30s to around 40F. Minor timing differences arise by Mon between the models, but the overall trend is for a slower arrival of the cold front and with the upper pattern amplifying quite a bit this makes sense. Expect increasing clouds ahead of the next front Sun night but have genly slowed down the main chance for for showers until Mon aftn/Mon night. Mild with lows in the 40s Sun night/Mon am and highs Mon mainly in the 60s (could even be near 70F in the SE if more sun develops and the precip is slower to arrive). High chc PoPs for now/40-50% all zones mon night. The ECMWF is slower by this time than the GFS/CMC so will linger PoPs through 12Z. Drying out/becoming partly-mostly sunny Tue with highs mainly in the 50s. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... Expect widespread flight restrictions today as snow spreads across the region. KRIC will likely experience IFR conditions from 12-18Z while KORF/KPHF will lag behind by several hrs with IFR conditions developing between 15-18Z and persisting to around 00z. KECG will likely not have IFR conditions until after 18z and will continue into this evening. KSBY will overall see only light snow showers with only brief vsby to 2sm possible. A N wind will gust to 20-25kt along the coast. Outlook: Clearing tonight with a breezy N wind near the coast. Predominate VFR then likely Thursday through Sunday as the trough departs well to the NE and a ridge builds across the region. && .MARINE... Marine Dense Fog Advisory has been cancelled. Any patchy fog will continue to dissipate through the morning. A surface cold front crosses the coast this morning with strong CAA lagging behind until the upper trough arrives later this evening into Thursday. NNW winds will increase to 15 to 25 knots this afternoon/evening with gusts to around 30 knots possible later this evening and tonight. SCAs have been into Thursday evening for the coastal waters where elevated seas and gusts to 25 knots may linger. SCAs for the Bay, Lower James, and Currituck Sound remain in effect from this morning into Thursday morning. High pressure settles over the area for the end of the week allowing for diminishing winds and sub-SCA conditions through the weekend. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...Winter Weather Advisory until 6 PM EST this evening for NCZ013- 014-030. Winter Storm Warning until 6 PM EST this evening for NCZ012. Winter Weather Advisory until 9 PM EST this evening for NCZ015>017-031-032-102. VA...Winter Weather Advisory until 3 PM EST this afternoon for VAZ048-061-062-069-509-510. Winter Weather Advisory until 6 PM EST this evening for VAZ064- 075>078-081>086-089-090-093-096-511>525. Winter Storm Warning until 6 PM EST this evening for VAZ060- 065>068-079-080-087-088-092. Winter Weather Advisory until 9 PM EST this evening for VAZ095- 097-098-100. MARINE...Small Craft Advisory until 7 PM EST Thursday for ANZ650-652- 654-656-658. Small Craft Advisory until 7 AM EST Thursday for ANZ630>633- 638. Small Craft Advisory until 10 AM EST Thursday for ANZ634. && $$ SYNOPSIS...TMG NEAR TERM...AJZ/TMG SHORT TERM...AJZ/MAM LONG TERM...LKB AVIATION...AJB/LKB MARINE...AJB is the U.S. government's official web portal to all federal, state and local government web resources and services.