Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 191749 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 1249 PM EST Thu Jan 19 2017 .SYNOPSIS... High pressure will build over the Mid Atlantic today. The high slides off the coast tonight as a front moves in by Friday. A complex low pressure system will affect the region early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Latest sfc analysis shows 1021 mb high pressure centered over OH/WV with a stalled frontal boundary across the SE states. Aloft, a mid-level ridge is located over the eastern CONUS. The sfc high will build east today and become centered over the Mid Atlc by this aftn as the ridge axis aloft also moves towards the area. This will allow for a dry weather day with light winds and partly/mostly sunny skies. Temps will be about 10 degrees above normal...highs in the mid/upr 50s most areas except lwr 50s near the coast. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... The high moves offshore this evening as moisture approaches from the west after midnight. Latest suite of models keep the fa dry through 09-12Z with light rain developing mainly west of I95 by 12-15Z. Pcpn remains liquid with lows upr 30s to near 40. Friday progged rather wet as a decent overrunning event setting up ahead of an approaching warm front. Likely pops spread across the fa throughout the day except categorical pops NWRN zones during the late morning. QPF one quarter inch or less. Highs in the mid 50s most areas. Best forcing pushes offshore Friday evening as low pressure moves east and out into the VA capes with weak high pressure building into the area. Evening pops will be confined to areas east of I95 with skies remaining mostly cloudy after midnight. Could see patchy fog/drizzle develop with lows 40-45. Latest data supports the weak high moving offshore Sat morning with moisture from the south quickly advancing NE across the Mid Atlantic region Sat afternoon. Thus, will carry chc pops mainly south of I64 after 18Z. Highs Sat in the upr 50s to lwr 60s. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A period of warm and wet weather is expected during at least the first half of the extended period. Upper level ridge axis lifts northeast of the region Saturday night and Sunday ahead of a shortwave lifting from the Deep South into the Mid-Atlantic. Meanwhile, a potent upper low tracks across the Southern Plains into the Gulf States Sunday. Deep layer southwesterly flow will advect anomalous precipitable water values into the region ahead of the approaching lead shortwave energy. Strong isentropic lift will result in widespread precipitation overspreading the region Saturday night into Sunday. Have retained likely POPs across the forecast area Sunday. Cannot rule out some convection across the southern local area Sunday, nearest the lifting warm frontal boundary. Highs Sunday in the mid to upper 50`s north to low 60`s south. The upper low ejects northeast into the Mid-Atlantic Sunday night as an associated area of low pressure lifts over the Carolinas. Likely POPs continue Sunday night thanks to anomalous moisture and impressive forcing for ascent. Lows in the mid to upper 40`s north to mid 50`s south. There remains some spatial differences with respect to the surface low placement and potential dry slotting into Monday, but will continue with high end chance to likely POPs as the upper low parks over the region. Highs in the upper 50`s to low 60`s. The upper and surface lows lift northeast of the region Tuesday, with drying conditions southwest to northeast. Highs Tuesday in the mid to upper 50`s. Upper/surface high pressure expected Wednesday ahead of the next approaching storm system. Highs generally in the upper 50`s to low 60`s. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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Sfc high pressure over the area will continue the VFR conditions through most of the 18Z forecast period. Expect the 3K FT BKN SC deck at SBY to dissipate by sunset. BKN CI will lower into a BKN AC deck by 12Z. Models don`t spread any pcpn east until after 14Z. Thus, only TAF site with pcpn will be RIC with MVFR cigs/vsbys in light rain/fog expected before 18Z. Outlook: IFR/MVFR conditions expected Friday afternoon as rain overspreads the etire area. The steady rain ends but expect areas of drizzle / fog Friday night into early Sat. Adverse aviation conditions expected into early next week as series of disturbances are expected to track across the area.
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&& .MARINE... Sfc high pressure builds over the waters today through late tonight with light and variable winds anticipated Thu aftn through Fri morning. Seas 2-3ft today...building to 2-4ft due to nly swell from a sfc low well off the Mid Atlantic coast. Waves 1-2ft. Sfc high gets pushed offshore late tonight as an upper low over the Plains today rotates up into the Midwest through Fri. Winds become se-s aob 10kt on Fri. A weak coastal trough is anticipated to develop Fri aftn/evening along a warm front that lifts nwd to roughly the VA/NC border and essentially stalls there through Sun. Winds become more n-ne by Sat morning...turning more e-se Sat aftn/night with speeds remaining no higher than 10kt during this time. The 2-4ft seas will persist into Fri and then subside to 2-3ft Fri night into Sat as the warm front moves over the srn waters. Waves continue at 1-2ft during the same timeframe. Meanwhile, a more vigorous low pressure system exits the Four Corners Region and swings across TX/OK and the Lower Mississippi Valley on Sun...pushing across the Southeast States Sun night and into the Mid Atlantic Region on Mon along the stalled warm front. The pressure gradient tightens in response to the incoming sfc low and winds become more onshore/e-se Sun through Mon. Speeds anticipated to increase to 10-15kt by Sun aftn and then increase to 15-20kt late Sun night into Mon as the sfc low nears the coast. Model guidance is not picking up on stronger wind speeds just yet, however stronger sustained speeds and the potential for gale gusts will be possible. Seas 3-4ft Sun are expected to build to 5-6ft late in the day through Sun night...locally higher to 6-9ft north of Parramore Island. Waves building to 2-3ft (possibly up to 3-4ft srn Bay) within the same timeframe. Seas build more uniformly on Mon with the sfc low passing over the waters with wave heights of 4-6ft south/6-10ft north. Waves 3-4ft srn Bay/2-3ft nrn Bay. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MAS NEAR TERM...MAS SHORT TERM...MAS/MPR LONG TERM...SAM AVIATION...MPR MARINE...BMD

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