Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 150011 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 711 PM EST Tue Nov 14 2017 .SYNOPSIS... High pressure will remain centered over New England through Wednesday. A weak cold front will drop across the region late Wednesday night, followed by high pressure returning Thursday into Friday. A strong cold front will affect the area over the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Latest analysis places the center of sfc high pressure (~1030 mb) over the St Lawrence Valley with weak sfc low pressure over the the southern Appalachians and a developing weak sfc trough off the mid-Atlc coast per latest MSAS pressure falls. Locally, the NNE flow continues to bring BKN/OVC stratocumulus to most of the CWA and this has kept temperatures steady through the aftn mainly in the upper 40s to lower 50s (overall more cloudy and a few degrees cooler than anticipated). Still expecting skies to become partly cloudy to mostly clear by around 00Z and this will allow temperatures to then fall off several degrees through the late evening. Upper level system passing off the GA/SC coast looks to help further deepen the aforementioned sfc trough off the NC/VA coast overnight and on Wed while the sfc high becomes centered over northern New England. For tonight, with skies eventually becoming mostly clear with light flow inland should see lows into the 30-35 F range along/west of I-95 corridor, with lows mainly in the mid 30s to around 40 F over eastern sections (locally in the 40s at the coast). On Wed, deep layer moisture looks to remain off the coast, but both GFS and NAM Bufkit soundings suggest shallow low level moisture pushes inland during the morning hrs with NE low level flow. Overall this means that skies look to become mostly cloudy Wed, earliest along the coast and by late morning/early aftn well inland. Will carry 20% PoPs along the coast, (not going higher as chance for measurable rain will be limited as there will not be saturation through the DGZ. Limited mixing and the clouds will keep highs from warming much compared to Tue despite significant rises in 850 mb temps. Highs Wed will avg in the low to mid 50s N/NW to the upper 50s SE. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
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The high slides off the coast Wed night, as low pressure swings through the upper Great Lakes. A cold front approaches from the NW and drops across the region very late Wed night/early Thu. That front will be moisture will carry just a 10-20% PoP most areas even with skies becoming cloudy to mostly cloudy. Will have a narrow zone of 30% PoPs over the MD eastern shore from 06-12Z Thu where a little more moisture pooling is depicted by the model consensus. Lows Wed night will mainly range from the upper 30s- mid 40s. Warmer and becoming mostly sunny Thu with a breezy downslope NW flow and went with the higher edge of guidance except over the NW. Highs on Thu in the lower 60s NW to the mid to upper central/S. Mostly clear and much colder again Thu night as cold sfc high pressure builds in from the upper midwest. Lows 30-35 NW and in the 40s SE. Highs Fri in the lower-mid 50s and mostly sunny.
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&& .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A potent frontal system will develop west of the region Friday night and approach the area during the day on Saturday. There are still a few timing differences between the models, but they have come into better agreement over the past couple of runs. The best chance for rain appears to be Saturday evening through Sunday afternoon. The front quickly exits the region by Sunday evening. Warm and breezy conditions are expected ahead of the front with highs climbing into the low to mid 60s. Lows drop into the low to mid 40s on Saturday night. Cooler conditions are expected behind the front with highs in the low to mid 50s on Sunday and upper 40s on Monday. Low temperatures will also be much colder with lows on Sunday night dropping down into the upper 20s away from the coast. Cool and dry conditions are expected for next week with temperatures remaining below normal. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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High pressure is centered over the Northeast Conus as of 00z, with low-level NNE flow continuing along the Mid-Atlantic coast. bkn-ovc stratocumulus has generally demonstrated a diminishing trend over the past few hours but there is still a band that extends from over the Chesapeake Bay across SE VA with cigs ~3.5-4.0kft. High pressure will remain centered N of the region tonight into Wednesday and will ridge swd into the VA Piedmont overnight, which should lead to a period of clearing. A weak surface low is expected to develop off the NC Outer Banks Wednesday and then will lift NE off the Mid-Atlantic coast Wednesday night. This is expected to bring bkn-ovc cigs back into coastal areas late tonight into early Wednesday morning, and then to all areas by 15-18z Wednesday. Cigs are expected to be MVFR or low-end VFR ranging from 1.5-2.5 kft near the coast, and 2.5-3.5 kft farther inland. Current guidance does suggest the potential for IFR cigs at ECG late Wednesday aftn and evening. Mostly cloudy but becoming VFR Wednesday night as a cold front approaches from the W, with a mainly dry frontal passage Thursday. Becoming breezy with a WNW wind and mainly sunny/clear conditions Thursday and Thursday night. Mostly clear Friday/Friday night. A cold front will impact the region over the weekend, with breezy SW flow ahead of the front Saturday, shifting to the NW in the wake of the front Saturday night and Sunday. At this time there is a 30-50% chc of showers Saturday night along the the potential for degraded flight conditions.
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&& .MARINE... Sfc high pressure is centered over the St. Lawrence River Valley this afternoon, and extends southward down the spine of the Appalachians. Decent pressure gradient along the mid-Atlantic coast is producing N winds 15-20 kt with some gusts to 25 kt over much of the marine area this afternoon (good enough of SCAs for all but the upper James, York and Rappahannock Rivers). Seas are generally running 4-6 feet; waves 2-3 ft. Winds should diminish enough to allow SCAs for the Bay/lower James and Currituck Sound to end this evening or either by midnight (Currituck Sound). Seas 4-6 ft; waves 2-3 ft tonight. A spoke of upper level energy is expected to cross the Mid Atlantic Region tonight and may allow a sfc coastal low to spin up off the northern OBX on Wednesday, then lift NE along off the mid-Atlantic coast Wed night. Although not expecting SCA winds at this time (mainly NE 10-15 kt, becoming NW Wed night), seas should remain elevated (4-6 ft). Therefore, have extending the SCA north of Cape Charles thru 10 pm Wed night and for the southern coastal waters until 10 am Thursday. Next frontal boundary crosses the marine area late Thurs with NW winds increasing to 15-25 kt by evening into Thurs night. Seas 4-6 ft; waves 2-3 ft. Winds diminish again on Friday while remaining NW to W. Latest 12z guidance continue to slow the progression of the weekend cold front, now set to arrive either late Sat or Sat night. Still expecting SSW winds to increase to SCA levels ahead of the boundary, then a decent northerly surge behind the front on Sunday. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ634. Small Craft Advisory until 7 PM EST this evening for ANZ630>632-638. Small Craft Advisory until midnight EST tonight for ANZ633. Small Craft Advisory until 10 PM EST Wednesday for ANZ650-652- 654. Small Craft Advisory until 10 AM EST Thursday for ANZ656-658. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...ALB/LKB LONG TERM...AJB AVIATION...AJZ/LKB MARINE...JDM is the U.S. government's official web portal to all federal, state and local government web resources and services.