Area Forecast Discussion
Issued by NWS Wakefield, VA

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472 FXUS61 KAKQ 161534 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 1034 AM EST Thu Feb 16 2017 .SYNOPSIS... High pressure builds along the Gulf coast today into Friday, as strong low pressure off the New England coast moves north to the Canadian maritimes. This area of high pressure then slides offshore of the southeast coast Friday into Saturday. A weak area of low pressure moves through the Carolinas Saturday night with high pressure returning by Sunday afternoon. && .NEAR TERM /THROUGH TONIGHT/...
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Current analysis indicating intense sfc low pressure centered near Halifax, NS (~968 mb), with ~1022 mb sfc high pressure centered over the western Gulf of Mexico. A cold upper trough is in place over NY/New England. The sky is mostly sunny across the srn half of the area this morning, with sct-bkn mid clouds over the Ern Shore, and a bkn-ovc deck ~7kft from nrn to e-central VA. For today, shortwave energy will continue to round the base of the upper trough, with 500mb heights of -2 std dev and 850 mb temperatures to -6C SW to -10C NE, which should yield highs only in the low-mid 40s over the N and upper 40s across the S even in a well mixed BL. Sky cover should average partly sunny to occasionally mostly cloudy NE to mostly sunny SW as a strong channeled vort max continues to pass over the area. A NW wind of 15 mph is expected inland to 15-20 mph closer to and along the coast, with gusts up to 30-35 mph possible over the Ern Shore (gusts mainly 25-30 mph elsewhere). Very dry/low dew pts this aftn, but with yesterday`s rainfall and fairly cold temperatures, Fire wx concerns should be minimal. The main upper trough will push offshore tonight into Friday morning, with a shortwave trough dropping sewd across the region, within NW flow aloft late tonight into early Friday. This combined with the commencement of mid-level WAA should produce increasing mid/high clouds, but dry conditions are expected to prevail. Lows tonight are expected to range from the mid 20s to around 30 F.
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&& .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Partly-mostly cloudy skies Friday morning become mostly sunny by midday and with low level flow shifting to the SW, highs moderate into the 55-60 F most areas W of the Bay, except 50-55 F over the NE (and upper 40s/around 50 F over the Ern Shore). Mid-level ridging builds front the Ohio Valley Friday night into the Mid-Atlantic by Saturday. Temperatures will continue to moderate Saturday with highs rising into the mid 60s to around 70 F (50s at the immediate Atlantic coast of the Ern Shore), after morning lows in the 30s. Clouds potentially increase Saturday aftn, mainly SW, as a srn stream system pushes into the Tennessee Valley. This system will be weak, but should see skies turn mostly cloudy Sat night with milder lows in the 40s to near 50 F. Models showing split in precip pattern with some light precip moving well N of the low into central VA, and another area of precip genly staying S/SE of the CWA. Will continue with mainly just a 20-30% PoP Sat night, with QPF amounts to be light/less than 0.10". && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... A weak coastal low/trough and an upper level trough will primarily pass south of the region Sun morning. There may be enough isentropic lift present for light rain showers across the srn half of the CWA during this timeframe. Conditions improve through Sun with clearing skies and high temps in the upper 60s inland/low-mid 60s closer to the coast (upper 50s to lower 60s beaches). Otherwise, high pressure returns to the region Sun night into Mon. Expect mostly clear skies with lows Sun night in the 40s and highs on Mon in the upper 60s inland /low-mid 60s closer to the coast (upper 50s to lower 60s beaches). A clipper system is expected to pass well north of the area late Mon night into Tue night, thus pushing the sfc high southeast of the local area and flattening the mid- upper level ridging. Forecast is generally dry with a very remote chance of showers passing across far nrn counties Tue night where a weak frontal boundary is expected to be. Lows Mon night in the 40s under mostly clear to partly cloudy skies. Increasing clouds Tue/Tue night. Highs Tue in the mid-upper 60s inland to mid 50s- lower 60s immediate coast. Lows Tue night in the 40s. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... High confidence that VFR conditions will prevail through the 12Z TAF period. Gusty WNW winds will pick back up over the next few hrs sustained northwest winds of 12-15 knots and gusts of 20-25 KT, mainly from 14Z-22Z. Skies to avg FEW-SCT southwest to SCT- BKN northeast but any Cigs would be 5,000 ft or higher. Lighter winds tonight, with increasing mid/high clouds after midnight. Outlook: VFR conditions are expected Fri/Sat. Low pressure tracks off the Southeast coast Saturday night and into Sunday bringing a chance for spotty light rain but overall conditions should be mainly VFR. High pressure returns later on Sunday and into early next week. && .MARINE... Latest surface analysis depicts deepening low pressure offshore of the Northeast coast with high pressure over the Southern Plains. The result is a northwest wind over the local waters. A brief lull in speeds is observed over the local waters early this morning ahead of a secondary front/cold surge. This front pushes offshore by daybreak as the Northeast low deepens. Northwest winds increase back to 20-25 knots with gusts to 30 knots early this morning. 15-20 knots with gusts to 25 knots in the rivers. Waves 2-4 feet and seas 4-6 feet. Surface low continues to deepen and lift over the Canadian Maritimes today as high pressure builds over the lower Mississippi River Valley. The result will be ongoing cold air advection and SCA conditions. Gust in the Bay become 25 knots this afternoon, but remain 30 knots over the coastal waters. Waves remain 2-4 feet and seas 4-6 feet. A high pressure ridge builds in from the west late today and tonight as cold air advection wanes, resulting in improving conditions through this evening. Expect sub-SCA conditions to return to all waters by midnight. Waves diminish to 2-3 feet and seas 3-4 feet. Sub-SCA conditions persist through Saturday with varying degrees of southwest to west flow. Speeds generally at or below 15 knots. Waves 1-2 feet and seas 2-3 feet. A front pushes across the waters Saturday night as low pressure develops along the southeast coast. Flow becomes northwest Sunday, but sub-SCA conditions prevail. High pressure returns early next week. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 4 PM EST this afternoon for ANZ635>638. Small Craft Advisory until 1 AM EST Friday for ANZ630>632-634- 650-652. Small Craft Advisory until 7 PM EST this evening for ANZ633. Small Craft Advisory until 10 PM EST this evening for ANZ654- 656-658. && $$ SYNOPSIS...LKB NEAR TERM...LKB/AJZ SHORT TERM...AJZ/LKB LONG TERM...BMD AVIATION...LKB MARINE...SAM is the U.S. government's official web portal to all federal, state and local government web resources and services.