Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 162043 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 343 PM EST Sat Dec 16 2017 .SYNOPSIS... High pressure builds across the Southeast coast tonight, and moves off the Carolina coast Sunday and Monday. The local area remains in between weak low pressure to the south and strong low pressure over Canada Tuesday. A cold front crosses the region Tuesday night into Wednesday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A region of zonal flow prevails across the central and ern Conus this aftn upstream of a trough over the southwest Conus and nrn Mexico. At the surface, high pressure is centered across AL/GA/SC. Sunny this aftn with a few high clouds over the MD Ern Shore. Temperatures are on the cool-side of seasonal averages and primarily in the mid/upper 40s (low 40s over the MD Ern Shore) with a light SW breeze. A mid/upper ridge will build across the Ohio Valley tonight as a shortwave trough lifts to the NE over the srn Plains. Surface high pressure will shift to the Carolina coast with the local area remaining clear and dry tonight with a calm to very light wind. Decent radiational cooling is expected tonight with temperatures quickly dropping into the 30s early this evening. Overnight lows are expected to be in the mid/upper 20s with low 30s for coastal SE VA/NE NC. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... High pressure slides offshore Sunday as a weak trough pushes across the Great Lakes. Some upper level srn stream moisture (basically the remains of the aforementioned srn Plains trough) will arrive ahead of this wave, which will result in increasing mid/high clouds Sunday aftn and evening. Highs Sunday range from around 50F N to the mid 50s S. Decreasing clouds Sunday night with lows ranging from the mid/upper 30s N to the low 40s SE. High pressure remains offshore Monday as the flow aloft remains zonal. Mostly sunny early Monday and then becoming partly sunny as a dampening srn stream wave pushes into the Tennessee Valley by the aftn. Mild Monday with highs generally 55-60F. The 16/12z model consensus keeps this system suppressed well S of the local area Monday night and it quickly moves offshore Tuesday as a nrn stream wave dives across the Great Lakes. Meanwhile, surface high pressure is forecast to be centered off the Southeast coast. Partly cloudy Monday night and Tuesday with the airmass continuing to warm. Forecast lows Monday night range from the upper 30s N to mid 40s SE. Quite warm Tuesday with highs in the 60s, and even potentially close to 70F if enough sun prevails. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The extended period will begin Tuesday night/Wednesday with progressive split zonal flow continuing to prevail over the central and ern Conus. A nrn stream wave passes across New England Tuesday night, which will push a cold front through the Mid- Atlantic. Meanwhile, a srn stream wave will track across the Tennessee Valley Wednesday and off the Carolina coast Wednesday night. 16/12z ECMWF/GFS/CMC demonstrate decent agreement with this system. However, the best forcing is progged to be S of the local area, so PoPs for rain are only 20-30% across far srn VA and 30-40% for NE NC. Cooler behind the front Wednesday with highs generally 50-55F (upper 40s far NE), after morning lows in the upper 30s N to mid 40s SE. Drier air pushes in from the NW late Wednesday night into Thursday with lows Wednesday night ranging from the low 30s N to upper 30s S, followed by highs Thursday in the upper 40s N to low 50s S. The large scale trend by Friday/Saturday is for a trough over the Great Lakes and a ridge off the Southeast coast. However, model agreement is lacking on the details, specifically with respect to the location of the cold front between these two features. PoPs are trended toward or slightly above climo for the very end of the forecast period, with temperatures generally remaining above normal. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... High pressure is centered over AL/GA/SC as of 18z and this is resulting in a 5-10kt WSW wind under a primarily sunny sky aside from a few patches of high clouds. High pressure becomes centered over the Carolina coast tonight with a mostly clear sky and a calm to very light wind. High pressure slides offshore Sunday and Sunday night as a weak trough approaches from the WSW. This will bring a period of bkn-ovc mid/high clouds Sunday aftn into Sunday evening. High pressure remains near the Southeast coast Monday through Tuesday with VFR conditions prevailing along with occasional mid/high clouds. Low pressure passes S of the region Wednesday with high pressure building N of the region Thursday. && .MARINE... All SCA headlines have been cancelled with this forecast package with winds down to 10-15 kt over the Bay/Sound and seas over coastal wtrs down to mainly 2-3 ft. Sfc low pressure rapidly pushes offshore today as high pressure builds over the SE states. Slight increase in pressure gradient this evening may lead to winds close to SCA criteria over the Bay, but confidence is not high enough attm to issue a headline. Otws, sub-SCA conditions over the next few days as the sfc high slides off the SE coast and low pressure passes well north of the local area with a lack of any CAA. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...AJZ/LKB NEAR TERM...AJZ SHORT TERM...AJZ/LKB LONG TERM...AJZ AVIATION...AJZ MARINE...MAS is the U.S. government's official web portal to all federal, state and local government web resources and services.