Area Forecast Discussion
Issued by NWS Wakefield, VA

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690 FXUS61 KAKQ 250831 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 431 AM EDT SUN SEP 25 2016 .SYNOPSIS...
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A backdoor cold front settles across the Carolinas today. High pressure will build across New England...ridging south into the area through early Monday. A second and stronger cold front will cross the region Tuesday.
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&& .NEAR TERM /THROUGH TONIGHT/... Latest wx analysis features sfc cool front oriented just south of the local area, extending from E NC back into far western VA and SKY. The front will continue to nudge south today as 1024+mb Sfc high pressure builds south from QC across New England through tonight. Already noting sct-bkn post-frontal stratus deck across the local area. Bufkit data continues to indicate slow improving trend this morning through midday across the Northern Neck and Eastern Shore counties as drier air drops south across the area. This should allow for low clouds to get mixed out through the morning along the coast Farther inland, weak/shallow isentropic lift and onshore flow will result in overcast conditions for much of the day along and west of I95. Highs today mainly in the low to mid 70s. After some short-lived clearing early tonight, clouds re- develop by midnight and through the overnight as the cool air wedge is reinforced by renewed isentropic lift, underneath upper ridge axis nudging in from the west. Sky cover ranges from overcast with areas of light rain or drizzle well inland across the piedmont to partly cloudy along the VA coast over to the MD Eastern Shore. Look for chilly early morning lows from around 50 MD Eastern mid 50s to around 60 central and south (mid to upper 60s along the SE coast. && .SHORT TERM /MONDAY THROUGH TUESDAY/... High pressure moves offshore of the New England coast on Monday as the next front approaches from the west Monday afternoon. Flattening of upper ridge will slow the advance of the front, and serve to break down the cool air wedge slowly from NW to SE Monday afternoon as the sfc high slides offshore. However, clouds should hold firm across the piedmont through much of the day, resulting in another mostly cloudy to overcast day Monday, variably cloudy along the coast. Highs in the mid to upr 70s. A strong cold front still on track to cross into the region late Monday night ahead of a potent northern stream trough. Moisture increases along the front with PW`s climbing above 1.75 inches along with marginal instability per Showalter values trending around 0 after 00z/Tue. Pcpn enters the region from the NW with highest pops Monday evening, spreading east as best forcing nudges from sw to ne Tuesday morning. Lows Mon night in the mid 60s. Models show possible weak s/w energy riding east along the boundary Tuesday. This will likely enhance pcpn and allow it to linger a bit longer especially along coastal sections. Likely pops linger across the Se zones through Tue. Kept thunder chcs in as well, again with modest instability lingering. Highs Tuesday in the low to mid 70s. QPF generally between 1/2 to 3/4 inch. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Medium range guidance continues to indicate anomalous heights over Canada through the period, as well as over the western Atlantic. A deep/anomalous upper low drops over the eastern Great Lakes region Wednesday, under the upper ridge. Ensemble and deterministic guidance continues to struggle with a more progressive versus blocked flow over the eastern CONUS. The result is a relatively low confidence forecast, but have trended more toward GFS/GEFS solutions. Tuesdays cold front progged to stall along the coast in deep layer southwesterly flow across the Mid-Atlantic. POPs taper off inland Tuesday night, with chance POPs remaining across the southeast forecast area. A series of upper level disturbances will lift along the frontal boundary Wednesday. The combination of waves lifting along the front and strong upward vertical motion will bring solid chance POPs back to the southeast local area and slight chance to low end chance inland. The upper low locates in the vicinity of the Mid Atlantic region Thursday. While the best moisture pushes offshore, will keep mention of slight chance to chance POPs Thursday and Thursday night to account for uncertainty and potential light rain. Thereafter, the upper low likely begins to slowly lift northeastward as the upper ridge over the western Atlantic begins to break down. With the upper low lifting away from the region Friday and Saturday, large scale subsidence over the region will result in a drying trend. Will keep chance POPs northeast Friday and retain silent POPs on Saturday. Slightly below normal temperatures forecast through the period, with highs generally in the low to mid 70`s. Lows range from the low to mid 50`s inland to mid 60`s along the coast. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... MVFR to low end VFR conditions across area terminals in post- frontal stratus deck this morning. Noting some localized IFR to LIFR (CIG/VIS) around KSBY, which should clear between 12-14z as drier air filters in and scours out low clouds. VFR conditions at SBY/RIC after 12z, with CIGS trending to VFR by mid morning at remainder of terminals. Will likely see low clouds linger west of KRIC as cool air wedge sets up. Will likely see a return to sub- VFR cigs and perhaps some patchy drizzle/sprinkles inland late Sunday night into Monday morning. Sub-VFR cigs possible at KRIC/KPHF ahead of the front Monday afternoon. The next chance for widespread precipitation will arrive Monday night into Tuesday ahead of a strong cold front. && .MARINE... Cold front has located south of the waters early this morning, as high pressure builds in from the north. North to northeast winds of 10 to 15 knots observed over the waters, with occasional gusts of 20 knots over the southern coastal waters. Have dropped SCA headlines for the lower Chesapeake Bay. Seas remain elevated thanks to distant tropical cyclone Karl and onshore flow, ranging from 3 to 5 feet. SCA headlines remain in effect for the coastal waters. Based on the latest guidance, have extended headlines through 1 pm this afternoon. Thereafter, seas subside to 3 to 4 feet. This mornings cold front lifts back to the north Monday as a cold front approaches from the northwest. Flow becomes south to southeast with marginal SCA conditions possible late Monday into Monday night. The front pushes across the region Tuesday, likely stalling along the coast Tuesday night and Wednesday. A weak pressure gradient progged over the region, but a cooler and drier air mass may result in at least marginal SCA conditions late Tuesday night. An upper level low is progged to drop into the region Wednesday and Thursday, resulting in unsettled weather conditions through the end of the week. Flow generally out of the north. && .HYDROLOGY... The Cashie River at Windsor remains in minor flood stage. The river is forecast to slowly fall below flood stage by late this afternoon. See FLSAKQ for details. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 1 PM EDT this afternoon for ANZ650- 652-654-656-658. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...MPR/MAM LONG TERM...SAM AVIATION...MAM MARINE...SAM HYDROLOGY... is the U.S. government's official web portal to all federal, state and local government web resources and services.