Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 240540 AFDAKQ Area Forecast Discussion National Weather Service WAKEFIELD VA 140 AM EDT Fri Mar 24 2017 .SYNOPSIS... High pressure slides offshore overnight and shifts farther eastward on Friday. A gradual warming trend then begins Friday through the upcoming weekend. A more active weather pattern is anticipated Sunday night into the first half of next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Sfc high pressure slides offshore overnight with continued clear skies. One last night of chilly readings with lows below freezing inland areas/MD Lower Eastern Shore (25-30F) and in the 30s far SE VA/NE NC coastal areas. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/... Dry with a gradual warming trend Fri through Sat as Canadian high pressure continues to push ewd/offshore. A warm front lifts NW of the area overnight...allowing warm air advection to commence on Fri with winds becoming more S-SW. Temperatures are expected to rebound to readings at to slightly above normal due to breezy SW winds gusting to around 20-25 mph inland VA/NE NC and up to 25-30 mph MD/VA Eastern Shore. Expect highs in the mid 60s most inland areas (mid 50s to lower 60s beaches and MD/VA Eastern Shore). Overall conditions will be dry as mid-upper level ridging and decent subsidence aloft dominates (i.e. best shower chances are along/north of the Mason-Dixon Line invof the warm front). Otherwise, mid-high clouds should stream across the region (especially north) within relatively flat, upper level flow through Fri night. Lows around 50F. Meanwhile, low pressure exits the Intermountain West Fri and tracks into the wrn Midwest Fri night. As the low struggles to cross the mid-Mississippi Valley Sat/Sat night, a secondary warm front extending from the low is expected to lift north through the area Sat aftn. This will allow for additional warming in continued SW sfc winds and a noticeable influx of moisture as dewpoints increase to around 50F. Although clouds should clear out briefly across the SE half of the area during the day (as is typical with a warm frontal passage), aftn cumulus development and increasing cirrus from the west will keep partly sunny wording in the forecast...mostly cloudy far nrn counties invof the warm front. Maintained highs for Sat in the in the mid 70s inland (upper 60s to lower 70s beaches). Continued warm Sat night with lows running about 10-15 degrees above normal. Lows in the lower 50s most areas (upper 40s possible Atlantic beaches of MD/VA Eastern Shore). Weakening sfc low in the Great Lakes finally gets kicked ENE by another low pressure system exiting the Intermountain West on Sun. Negative tilting of the mid-upper lows will slow the advancing (and weakening) sfc cold front associated with the Great Lakes low. This will also slow the arrival of incoming precip into the Eastern Piedmont until late Sun aftn (or even possibly not arriving until early evening). High temps expected to reach the lower 70s most inland areas (60s beaches). A combination of instability parameters are not lining up for favorable/widespread thunderstorm development Sun aftn/early evening. Best factors to overcome the meager instability will be the presence of weak seabreeze boundaries with SE-S sfc winds, and a veering wind profile with height (albeit weak 0-6km shear of roughly 30kt). Taking this into consideration and knowing that the region will be well within a warm sector, cannot completely rule out diurnally-driven thunderstorms in the aftn. Have therefore added a slight chance for thunder into the forecast. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Medium range period features a mild period, courtesy of surface high pressure oriented just off the Mid-Atlantic/southeast coast. Main weather features of note a couple of mid/upper level lows, which will bring scattered light precipitation late in the weekend and again by Tuesday. The first of these disturbances traverses across the central/southern Plains on Saturday, dampening as it crosses E- NE into the Ohio Valley and Eastern Great Lakes on Sunday and into the northeast on Monday. This feature will allow for some isolated to scattered showers Sunday night into early on Monday. QPF will be limited with this feature. Despite increasing PW values, minimal instability and steadily weakening dynamics/forcing remain maximized well off to our N-NW. Therefore, high end chc to likely pop is in place for Sunday night over our western/NW tier of the area for sct/numerous showers. Region remains mild in the warm sector with southerly flow bringing highs in the upper 50s to 60s Northern Neck and MD Lower Eastern Shore...with upper 60s to low 70s inland for early next week. For the middle of next week...attention turns to a second southern stream disturbance, which is expected to track east/northeastward from the CA coast...across the Plains and Mid-South Late Sat-early Monday. There remains some significant disagreement with the GFS/ECMWF, with the ECMWF and its member ensembles remaining more progressive and flatter. Will lean in the ECMWF direction with the GFS Parallel and GEFS seemingly trending in this quicker direction as well. Still, this system will be a bit stronger than the weekend system but it too will weaken as it pushes across the eastern third of the conus Monday through early Tuesday. So while would translate to another period of showers late Monday night into Tuesday afternoon, system will again be progressive. Given the timing, will mention slight chance of thunder Tuesday afternoon west of the Bay. Remaining mild, with highs in the 60s to near 70 Eastern Shore...mid 70s to near 80 South central VA/Interior NE NC. Shortwave ridging rebuilds behind this system for Wednesday. Highs remain mild through the period, with 50s and 60s over the northern neck of VA into MD, with highs well into the 60s to Mid 70s inland. Early morning lows mainly in the 40s to low 50s southern sections. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... High pressure/fair weather prevails over the region this morning, with SKC conditions observed. Surface winds are generally southerly at or below 10 knots. High pressure slides offshore today as a storm system tracks into the Midwest. Southwest winds increase this afternoon, with gusts to 25 knots across the region. A scattered deck of mid level clouds is expected this afternoon, with SKC conditions expected KECG. OUTLOOK...Dry weather continues into Sunday morning. Scattered showers are expected Sunday afternoon and night. Unsettled conditions are forecast to continue Monday and Tuesday. && .MARINE... Latest obs reflect Northerly flow across the waters this afternoon, with surface high pressure in place over the region. SCA headlines have been dropped for all waters except for ANZ658 south of the VA/NC border to Currituck Beach Light through 23z/7pm EDT. Seas have fallen off to 2-3 ft north, 3-4 ft central waters, and 4-5 ft across the far southern Coastal Waters. Sfc high pres slides off the coast tonight through Friday... with winds becoming SW Fri and lingering through Sat. Pressure gradient tightens tomorrow afternoon, with developing low pressure over the plains. Southerly flow increasing to ~15 knots by Friday afternoon. While nearshore winds will be elevated and gusty tomorrow and Sat afternoons, given still cool water temps...will undercut guidance slightly and keep waters below any SCA thresholds for now. The next front crosses the waters early next week...w/ relatively benign marine conditions expected over the weekend in SSW winds mainly aob 15 kt. Seas averaging 2-3 ft...waves 1-2 ft. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...BMD NEAR TERM...BMD/JDM SHORT TERM...BMD LONG TERM...MAM AVIATION...SAM/LSA MARINE...MAM

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