Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 171837 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 137 PM 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 SATURDAY/... 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 /SATURDAY NIGHT THROUGH WEDNESDAY/...
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Milder spell of wx through the extended forecast pd. Pattern evolving fits transition of MJO through phase 4 toward phase 5...leading to aoa normal temperatures. Other than a very wk upper level system tracking off SE CONUS coast Sun...sfc hi pres and upper level ridging will be dominant Sun into Mon. By late Mon...storm system expected to track into the wrn Great Lakes...w/ its trailing cold front approaching the mtns. That front will make progress across the local area Mon night-early Tue w/ potential SHRAs (though 12Z/17 ECMWF a tad slower than 12Z/17 GFS attm). Drying/clearing out and a bit cooler (returning to near seasonal levels) for Tue afternoon-Wed. Lows Sat night ranging through the 30s. Highs Sun in the l50s on the ern shore to 55-60F elsewhere. Lows Sun night mainly 35-40F. Highs Mon in the m50s on the ern shore to the u50s-l60s elsewhere. Lows Mon night in the u30s to l40s. Highs Tue in the l50s on the ern shore to the m-u50s elsewhere. Lows Tue night in the l-m30s. Highs Wed in the u40s-l50s.
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&& .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... Slow moving cold front is pushing through the region accompanied by a broad area of light to moderate snow. Widespread MVFR/IFR conditions perists as the area of precipitation moves eastward. SBY may experience a brief period of light snow but MVFR/IFR clouds will prevail through the afternoon and early evening. The snow has not reached ORF and ECG at 18Z and is expected to start anytime now at PHF. Warmer temps will likely see precip start as light RA at ECG later this afternoon before turning into snow. Winds will generally be N-NE with gusts 15-25 kt through the early evening. Outlook:Clearing tonight with a breezy N wind near the coast. Predominate VFR after midnight 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...
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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 6 AM EST Thursday for ANZ635-636. Small Craft Advisory until 11 AM EST Thursday for ANZ630>634- 638.
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&& $$ SYNOPSIS...TMG NEAR TERM...AJZ/TMG SHORT TERM...AJZ/MAM LONG TERM...ALB AVIATION...AJB/JEF MARINE...AJB

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