Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 222242 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 642 PM EDT SUN MAY 22 2016 .SYNOPSIS... A trough of low pressure will linger over the Mid Atlantic through Monday. This trough will gradually move offshore Monday night into Tuesday. An upper level ridge will build in from the west by the middle of the week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Some drying noted across the piedmont early his evening as one impulse moves east towards the coast with a second impulse progged to drop south late this evening and ovenight. Adjusted grids a bit next few hrs with some partial sunshine and across the piedmont from time to time...most notable across the sw piedmont where more clearing has taken place. Also lowered pops to chc most places west of I95 per crnt radar trends. Not getting to excited about less rain as clouds quickly fill back in by late evening with the next batch of rain / drizzle expected after midnite. The upper trough closes off tonight as it settles over SE VA and Eastern NC tonight into Monday morning, with h5 heights remaining on the order of ~-2 st dev. Mostly cloudy to overcast conditions continue overnight. Likely pops (rain/drizzle) edge s along and south-southeast of I-95 and I-64 tonight as the best area of lift gradually pinwheels southeast over the area overnight into Monday morning from central/e-central VA south into southeast VA. Continued mostly cloudy to overcast with early morning lows Monday mainly in the low/mid 50s.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Upper level low will continue to slowly wobble off of the mid- atlantic coast through the day, eventually sliding offshore by monday night. This will produce more in the way of sct to numerous showers on Monday, mainly in the afternoon and evening. Showalter index numbers/LI values remain modestly/minimally unstable. Nevertheless, have maintained a slight chc for thunder inland as the upper cold pool pushes across. Temps once again a touch below normal. Look for Monday maxima to top out in the upper 60s/around 70 inland, with lower to middle 60s along the southeast coast and immediate coastal locations. Evening stabilization should allow for partial clearing inland, with any areas of showers to diminish quickly after sunset into Monday night, though pops linger a bit later into the night over the Eastern Shore. Pops drop off even further after midnight as the upper low continues to push farther off toward the New England coast into Tuesday morning. Remaining mild with early morning lows Tuesday morning in the lower-middle 50s, under a partly to mostly cloudy sky. The Tuesday/Wednesday time frame will be characterized by gradually improving conditions across the region behind the departing upper low, as high pressure at the surface and aloft slowly builds across the region in its wake for the mid week period and beyond. While a gradually clearing sky/dry wx is anticipated inland (actually mostly sunny by afternoon in the piedmont), mostly cloudy conditions and some slight to low end chance pops continue along eastern third of the area. This is in association with one last upper disturbance rotating through behind the upper trough. Again, while surface-based instability looks to be minimal, Showalter numbers indicate some modest, mainly elevated, instability. Will therefore continue with thunder mention. Warmer on tuesday with highs in the upper 60s to around 70 coastal locations, low to mid 70s along the coast and mid 70s to near 80 degrees inland. Moderating/warming temperatures continues on Wednesday, as 1024+mb surface high pressure slides offshore, as upper ridging build east. Deep layered W-SW flow will bring increasing temps and moisture across the region, though with PW values on the order of 0.50 to 0.75", and with models continuing to trend down with modeled rain chances, will keep pops out for Wednesday. For the first time in a couple of weeks, temps trend back up above climo area-wide on Wednesday, with forecast maxima in the upper 70s to low 80s over coastal sections along the Eastern Shore, low to mid 80s southeast VA/NE NC coast, and mid to upper 80s inland. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Bermuda sfc high pressure resides over the wrn Atlantic Ocean through the long term periods as upper level ridging moves over the ne CONUS during this time. Although the ridge becomes more pronounced Fri through Sun, weak waves of energy/moisture are expected to stream across the wrn fringes of the ridge. QPF is being depicted each aftn/evening through Sat, however this appears to be overdone given lack of preferred dynamics and lack of definitive upper level features to aid lift for convective development to occur. Held onto slight chance POPs in far nw counties Thu aftn/evening and then slowly migrate them ewd Fri/Sat. Current thinking is that the end result will be high clouds streaming through the region rather than light rain showers with isolated thunder. Meanwhile, low pressure begins to develop over the Caribbean on Fri and is expected to drift twd a location off the FL/GA coast by Sun. Will maintain slight chance POPs for Sun/Sun night across Central VA due to pop-up showers developing on the mtns and also in ne NC since wraparound moisture could make it into this area during this timeframe. Overall, high temps should run around 5-7 degrees above normal Thu-Sat. Highs generally in the mid 80s (mid 70s-low 80s beaches). Low temps also running about 5 degrees above normal Thu-Sat nights. Cooler Sun in anticipation of more clouds with highs in the lower 80s inland and in the mid-upper 70s beaches. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... A moist and unsettled pattern will persist thru Monday, as an upr low drops southward into/over the fcst area. This feature will maintain MVFR/IFR conditions across the region. Most TAF sites have become MVFR as of 17Z, and expect MVFR to dominate through 00Z. Exception will be KSBY, where IFR will prevail. Scattered showers becoming more widespread during the last hour, and these will affect all terminals but KECG, which looks to remain dry through much of the 18Z TAF period. Latest METARs suggest ceilings will remain MVFR in showers, so have limited amount of IFR through 00Z. Expect IFR to dominate after 00Z, as cool/moist flow around upr low persists. In addition, rain likely to become more widespread, and have accounted for that in TAFs. Upr trof begins crossing region Monday, with dry air in low/mid levels trying to filter into the region as the day wears on. This should allow for ceilings to become MVFR everywhere, with some VFR possible toward the end of the TAF period. The upr low and associated trof will finally slide e-ne of the region Tue aftn, with slowly improving flying conditions. OUTLOOK...High pressure surface and aloft builds over the Mid Atlc States with mainly dry weather Tue aftn thru Fri. && .MARINE... Sfc low pressure system that impacted the Mid Atlantic coast yesterday is now located off the New England coast this aftn with a frontal boundary extending down along the Southeast coast. A new sfc low is starting to develop invof the Carolinas and is expected to slowly track nne to just off the Mid Atlantic coast late tonight into Mon evening...then into New England on Tue. Meanwhile, an upper level trough sits over the region through Mon before gradually sliding off the coast Mon night and tracking into New England on Tue. Winds generally n 10-15kt this aftn will become ne 15-20kt for the Bay/Sound/all coastal waters early Mon morning. Expect gusts to around 25kt coastal waters and mouth of the Bay during the morning. Seas currently 3-4ft srn waters/4-6ft nrn waters. Seas become 4-5ft all coastal waters by late this to 5-6ft Mon morning...then subside to 4-5ft Mon aftn. For srn Ches Bay, 2-3ft waves will build to 3-4ft Mon morning and then subside to 3ft in the aftn. For nrn Ches Bay, waves will average 2-3ft. SCA flags in effect for Sound, all Bay zones, and all coastal waters through various end times on Mon. Please refer to the Marine Weather Message (WBCMWWAKQ) for specific details. Wind speeds diminish Mon aftn as tightened pressure gradient shifts ewd beyond 20nm. A secondary increase in wly winds may be possible late Mon night into Tue morning for the mouth of the Bay and coastal waters south of Cape Charles Light as sfc high pressure starts to build into the region from the west, however speeds of 10-15kt should keep the aforementioned areas (and Currituck Sound) out of SCA flags attm. Conditions finally quiet down Tue through Fri. Winds will generally be s-sw aob 15kt. Seas 2-3ft/waves 1-2ft. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 4 AM to 1 PM EDT Monday for ANZ632- 634. Small Craft Advisory from 7 AM to 4 PM EDT Monday for ANZ633. Small Craft Advisory from 4 AM to 10 AM EDT Monday for ANZ630- 631. Small Craft Advisory until 1 AM EDT Tuesday for ANZ650-652-654. Small Craft Advisory until 8 PM EDT Monday for ANZ656-658. && $$ SYNOPSIS...MAM NEAR TERM...MPR/MAM SHORT TERM...AJZ/MAM LONG TERM...BMD AVIATION...TMG/WRS MARINE...BMD is the U.S. government's official web portal to all federal, state and local government web resources and services.