Area Forecast Discussion
Issued by NWS Wakefield, VA

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064 FXUS61 KAKQ 180006 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 706 PM EST Sun Dec 17 2017 .SYNOPSIS... The Mid Atlantic region will reside in between weak low pressure along the Gulf coast and strong low pressure over Canada tonight through Tuesday as high pressure becomes centered off the Southeast coast. A cold front pushes through the region Tuesday night then stalls over the Carolinas on Wednesday. Low pressure moves along the front Wednesday and pushes off the southeast coast Wednesday night. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A weakening shortwave trough is tracking across the Ern Great Lakes and nrn Mid-Atlantic this aftn and will continue to track ENE this evening and tonight while largely shearing apart. This system has managed to pull some mid level srn stream moisture newd resulting in mostly cloudy to overcast conditions this aftn. The moisture profile remains rather dry below 850mb through this aftn and evening and ascent is weak, so only a few light sprinkles are expected at most, and will keep PoPs below 15%. Drier air arrives from the WSW after 06z and rapid clearing is expected from SW to NE late tonight. Temperatures this aftn are primarily in the mid 40s to around 50F, and should only gradually drop through the 40s this evening with cloud cover. There should be a few hours for radiational cooling once the sky clears (especially inland), so have trended lows on the cool- side or slightly below guidance. Forecast lows range from the low/mid 30s well inland to the upper 30s/around 40F at the coast. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... High pressure remains offshore Monday as the flow aloft remains zonal. Mostly sunny Monday with only a few high clouds streaming through strong westerly flow aloft. Mild with highs in the mid/upper 50s N to the low 60s S. High pressure continues to prevail in vicinity of the Southeast Coast Monday night and Tuesday. Partly cloudy to mostly clear/sunny with above normal temperatures. Forecast lows Monday night range from the upper 30s N to mid 40s SE. A WSW low level flow will make for quite warm conditions on Tuesday with highs well into the 60s, and potentially be close to 70F over srn half of the area if enough mixing occurs. Progressive split zonal flow will continue over the central and ern Conus Tuesday night and Wednesday. 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 Tuesday night and across the Carolinas Wednesday. 17/12z GFS/ECMWF/CMC generally keep the deeper moisture along and S of the VA/NC border with the NAM a nrn outlier. Forecast PoPs for Wednesday are 30-50% for NE NC/20-30% for srn VA, with a slight chc up to roughly a FVX-RIC- MFV line. Lows Tuesday night are generally in the low/mid 40s (upper 30s far NE) and highs Wednesday range from the upper 40s NE to the low/mid 50s central and S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Drier air pushes in from the NW late Wednesday night into Thursday as high pressure builds N of the region. Lows Wednesday night range from the upper 20s/around 30F N to the mid/ upper 30s SE, followed by highs Thursday in the mid 40s N to low 50s SE. The large scale trend by Friday/Saturday is for a trough over the Great Lakes and a ridge off the Southeast coast. Only a gradually warming trend is expected Friday with limited mixing and forecast highs range from the low 50 NW to low 60s SE after morning lows in the 30s. The 12z model consensus keeps a cold front well NW of the area Saturday with high pressure off the Southeast coast and southerly flow over the region. Forecast highs are in the upper 50s to mid 60s at this time, but there is the potential for higher values if enough sun and mixing occur. For the Christmas eve/Christmas day timeframe there remains run-to-run differences with respect to the location of the cold front. Temperatures could be well above normal if the front remains to the NW, while near to slightly above normal temperatures along with a chc of rain would be expected if the front settles over the region. PoPs are trended toward or slightly above climo for this time period. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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VFR conditions are expected for all sites through the 00Z TAF period. Mid-level clouds with bases generally between 6000 to 9000 feet have moved into the region this evening. A few sprinkles/light rain showers will be possible through the evening, but restrictions are not expected. Skies clear later tonight and Monday morning with mainly sunny skies anticipated for Monday afternoon. Outlook: High pressure remains near the Southeast coast Monday night through Tuesday with VFR conditions prevailing along with occasional high clouds. Low pressure passes south of the region Wednesday, with a 20-30% chance of light rain across southern VA and a 30-50% chance of light rain over northeast NC. High pressure builds north of the region Wednesday night and Thursday. High pressure slides offshore by Friday.
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&& .MARINE... No headlines in the short term tonight thru Tue. Late this aftn, high pressure was cntrd just off the Mid Atlc coast, with a frontal bndry laying west to east acrs the OH valley into PA. That front will lift NNE into/thru New England tonight thru Tue, as high pressure again will build in fm the west. Strong low pressure over Canada will then drag a cold front through the waters Tue night/Wed morning, with low pressure passing just south of the area Wed into Wed night. High pressure will build in fm the north late Wed night and Thu, then pushes into the Atlc late Thu night and Fri. && .CLIMATE... Have gone with missing data for RIC temperatures Sat Dec 16th as ASOS was unrepresentative (being too warm by 5-10 degrees). Observers at Airport will be augmenting data as necessary today. && .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...AJB MARINE...TMG CLIMATE...

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