Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 211449 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 1049 AM EDT Wed Mar 21 2018 .SYNOPSIS... Low pressure off the Virginia Capes early this morning, will intensify off the Delmarva coast this afternoon, before gradually pushing well off to the northeast tonight. High pressure over the midwest will gradually build into the area Thursday and Friday. Low pressure moves east from the mid Mississippi Valley on Saturday and tracks through the Carolinas on Sunday. && .NEAR TERM /THROUGH TONIGHT/...
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Latest analysis indicating ~993mb sfc low pressure intensifying off the VA Capes. Precip shield is best organized from central VA to NE MD and sern PA. Accumulating snow is occurring from the Piedmont across central VA toward the Nrn Neck. Snow accumulation over these areas have averaged 1-3" through late morning. Temperatures range from 30-32F well inland to the upper 30s along the coast. Choptank River bridge webcam indicates snow is mixing in near Cambridge. Rain is prevailing closer to the coast with perhaps some sleet mixing in with heavier pcpn rates as 1000-850mb thickness rates are falling. The surface low will deepen through the day, while shifting NNE off the Delmarva coast by late morning and aftn. The general trend in model guidance has been for a little faster shift to the north of the the deep lift through the DGZ this morning. As such, expecting bulk of accumulating snow over much of the advisory zones to occur this morning into early aftn with just scattered snow showers (or potentially rain/snow showers by mid to late aftn. The upper level system slides offshore from 18-21Z during the aftn with the overall system becoming stacked and nearly stationary off the coast during the 18-00z time period. This will bring the potential for banded pcpn (in the form of snow) across the Delmarva and perhaps the Nrn Neck back west to Caroline County. Likely to categorical PoPs everywhere through through midday today as the forcing from the upper level system taps into moisture, and categorical PoPs over the Ern Shore into the aftn. Thicknesses suggest rain will take longer to mix with snow over the Ern Shore, mainly not until the aftn (Dorchester may become all snow for this morning), then becoming all snow by aftn evening. Farther W (I-95 corridor to the Piedmont) thicknesses suggest all snow while pcpn occurs, with snow tapering off from SW-NE during the aftn, and possibly mixing with light rain at the tail end. A cold rain for SE VA/NE NC could mix with some snow this aftn/early evening. The current forecast is for 3-5" for Louisa, Caroline County and the Nrn Neck, and Somerset/Wicomico/Dorchester MD. These areas have a winter storm warning. Elsewhere, 1-3" of snow is forecast in a corridor along a FVX- RIC-WAL line where winter weather advisories are in effect. The primary impact will be falling snow with conditions improving once the snow ends. Accumulation on roads will be dependent on intensity, otherwise, expected accumulation mainly on the grass and elevated surfaces. Accumulation farther S should be 1" or less, and little to no accumulation for far SE VA/coastal NE NC. Highs today will be in the mid 30s where snow falls to the upper 30s/low 40s where rain prevails. Highs in south central VA may rise to the lower 40s later in the aftn as the precip intensity diminishes. By the evening, mainly just scattered snow showers with the exception of the ern shore where a more significant additional snow accumulation is expected after sunset. Drier air look to finally win out even acrs the eastern shore by around midnight or shortly thereafter as the sfc low is progged to then shift NE twds the New england coast. This will bring an end to any additional accumulating snow. Becoming partly cloudy most areas after midnight, except staying mostly cloudy on the eastern shore. Lows range from the mid/upper 20s NW to the low 30s SE. Some re- freezing is expected to occur early Thursday morning especially if the (partial) clearing does occur late tonight.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY/... Upper low will be off the New England coast thu, with another one progged to dive SE from the upper Great Lakes Thu night and Fri. This will keep temperatures well below normal for late March. Highs Thursday in the mid to upper 40s north to around 50 F to the lower 50s over southern VA and NE NC (possibly cooler over the MD Ern Shore depending on snowfall totals). Lows Thursday night range from the mid 20s to low 30s, with highs Friday in the mid-upper 40s N to lower 50s S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Region remains influenced by large scale upper trof through most of the extended period. Area is between systems Friday night and most of Saturday. A shortwave trof will be approaching from the west Saturday night, and move across the area on Sunday. Latest 00Z GFS/ECMWF remain somewhat at odds with regard to how far north precip gets with this shortwave. Have gone with a blended solution, which gives a chance of rain/snow across much of the area. Shortwave moves offshore Sunday night, with ridging surface and aloft gradually building into the region Monday through Tuesday. Overall, cold high pressure building in from the the NW will provide a continuation of below/much below normal temperatures for much of the forecast period. For temperatures, Highs Sat mid 40s to around 50 F. Lows Sat night generally 30-35, with some upper 30s NE NC. Highs Sun in the 40s to around 50 F, and Mon mid to upper 40s N/DELMARVA to mid 50s southern portions of interior NE NC. highs Tuesday around 50 Lower MD Eastern Shore to the upper 50s interior NE NC. Lows Sunday night/Monday night in the low to mid 30s. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... Low pressure is located off the VA Capes as of 11Z, with high pressure centered N of the Great Lakes ridging swd into northern VA. IFR/LIFR conditions prevail at all terminals and should genly stay that way through the aftn/early evening. Area of precipitation currently advancing from SW to NE across the region with mainly snow in the NW Piedmont and now at KRIC with rain at other terminals. Rain will continue to change to snow from NW to SE across the area through the remainder of the morning hrs, but will be slow to make it to the coast and eastern shore. Will probably take until 15-18Z at KSBY/KPHF, and KORF probably after 18Z. A N/NW wind of 10-15kt with gusts to around 20kt is expected, especially near the Bay/Ocean. Accumulating snow potentially lingers at KSBY this evening. Otherwise, drier conditions arrive later tonight, with dry and VFR conditions to prevail Thursday and Friday. Low pressure approaches from the W late Saturday, with the potential for sub- VFR flying conditions Sat night into Sunday. && .MARINE... Current observations as of 730Z show North winds of 15 to 25 knots over the waters with gusts to 30-35 knots as low pressure intensifies off the coast. Seas range from 8 to 13 feet across the northern coastal waters and 7 to 10 feet across the southern coastal waters. Waves range from 3 to 5 feet (up to 6 feet at the mouth of the Bay). A Gale Warning remains in effect for the northern two coastal water zones and Small Craft Advisories remain in effect the rest of the waters. Low pressure will continue to develop off the Mid Atlantic coast this morning and slowly lift NE off the Delmarva and New England coasts today into Thursday. Went ahead and dropped the Gale Warning from Parramore Island to Cape Charles Light as guidance has continued to back off slightly on the winds today. Could still see an occasional gust to 35 knots in this zone, especially out 20 nm. Otherwise, Small Craft Advisories remain in effect for all other marine zones through Thursday afternoon. Expect N-NW winds of 15 to 25 knots with gusts to 30 knots with elevated seas between 8 and 13 feet north and 7 and 10 feet south. Low pressure moves away towards the northern Atlantic late Thursday through Friday allowing for conditions to slowly relax. Small Craft Advisories may persist into early Friday for the coastal waters due to seas remaining at or above 5 feet. High pressure finally builds over the area Saturday before another low pressure system potentially impacts the waters Sunday. && .TIDES/COASTAL FLOODING... Coastal Flood Advisories remain in effect along the Atlantic Coast through late tonight. Increased swell energy in the wake of a series of developing low pressure areas will allow for elevated water levels and the potential for some minor flooding. Guidance continues to indicate tide levels of 1 to 2 feet above normal through tonight. Stiff north/northwest winds should limit the flooding threat in the Bay and Rivers, but a few locations may approach action stage through the next couple of high tide cycles. && .AKQ WATCHES/WARNINGS/ADVISORIES...
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MD...Coastal Flood Advisory until 4 AM EDT Thursday for MDZ024-025. Winter Weather Advisory until midnight EDT tonight for MDZ024- 025. High Surf Advisory until 8 PM EDT this evening for MDZ025. Winter Storm Warning until midnight EDT tonight for MDZ021>023. NC...Coastal Flood Advisory until 4 AM EDT Thursday for NCZ102. VA...Winter Storm Warning until 6 PM EDT this evening for VAZ048- 509-510. Winter Weather Advisory until 6 PM EDT this evening for VAZ060>062-068-069-511>517. Coastal Flood Advisory until 4 AM EDT Thursday for VAZ098>100. Winter Weather Advisory until midnight EDT tonight for VAZ099. High Surf Advisory until 8 PM EDT this evening for VAZ099-100. Winter Weather Advisory until 9 PM EDT this evening for VAZ078- 082-083-085-518>520-522. Winter Storm Warning until 9 PM EDT this evening for VAZ064- 075>077-521. MARINE...Small Craft Advisory until 4 PM EDT Thursday for ANZ630>632- 634-654-656-658. Gale Warning until 7 PM EDT this evening for ANZ650-652. Small Craft Advisory until 1 PM EDT Thursday for ANZ633- 635>638.
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&& $$ SYNOPSIS...LKB NEAR TERM...AJZ/LKB SHORT TERM...AJZ/LKB LONG TERM...LKB/WRS AVIATION...LKB MARINE...AJB TIDES/COASTAL FLOODING...AKQ is the U.S. government's official web portal to all federal, state and local government web resources and services.