Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 290610 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 210 AM EDT SUN MAY 29 2016 .SYNOPSIS... High pressure will push farther off the Mid Atlantic coast tonight. Tropical storm Bonnie will approach the South Carolina coast overnight, and will linger and weaken along the coastal Carolinas through the holiday weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... The current surface analysis continues to show high pressure well off the VA/NC coast, and ridging back into the Mid-Atlantic region. TS Bonnie (a minimal 35kt storm) is about 100mi se of Charleston, SC. Aloft, strong upper level ridge centered offshore is still ridging back west into VA. Another mild evening prevails across the local area, with the upper ridge holding strong and leading to mostly clear conditions over the CWA. Temperatures across the area this evening are generally in the upper 60s to mid 70s. A large-scale zone of subsidence continues to control the sensible weather locally, with dry conditions expected to continue through 06z, and only a slight chc PoP across the far srn counties from 06-09z. Models show the upper ridge buckling e-ne late tonight/early Sun, with TS Bonnie, approaching the SC coast. PW values AOA 2" expected to push into ne NC after 09z, and expand N into srn VA by 12z. The latest high-res guidance and the 28/18z NAM/GFS suggest PoPs begin to increase across the Srn tier VA counties and ne NC between 09-12z. Warm and becoming more humid tonight with increasing moisture and clouds...lows range from the low-mid 60s north/central zones to upper 60s/near 70 F south. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... Tropical Storm Bonnie forecast to slow down and linger along the SC coast on Sunday, before lifting ne and lingering along the Carolina coast through Mon. More uncertainty in track develops thereafter. Refer to discussions issued by the National Hurricane Center for the official track and forecast. An unsettled period will dominate the short term, with a warm and quite humid airmass in place. Expect a chance of showers in the morning, expanding NNW and becoming more widespread by late morning/aftn. Models still suggest greatest lift and instability to be inland from the coast along an inverted trough by aftn and will continue forecast with highest POPS/80% to be along/west of i-95 by aftn. Accordingly expect to see numerous periods of rain, falling moderate to heavy at times. Highs on Sun generally in the upper 70s wrn 2/3 to to lwr 80s acrs the eastern 1/3. The low is slow to weaken acrs the Carolinas and get slowly transported NE Sun night/Mon as upper level trough from the W tries to push through. The increasing support from the upper levels may lead to the most widespread precip for the entire event Sun night. Potentially very wet conds, with occasional moderate to heavy showers are expected in the modified tropical airmass. Will have likely to categorical POPS Sun night into Mon morning, with likely POPS lingering into Monday aftn/evening along the coast. Warm and humid with early morning lows 65-70 F Monday morning and highs in the upper 70s/lower 80s on Memorial Day. Disagreement amongst deterministic models by Tuesday, with the 12z/Operational GFS wanting to dry western portions of the area out under developing weak sfc ridging, The ECMWF is slower to clear out the sfc low altogether, ejecting it quicker to the NE. Will continue to follow a WPC blended solution, weighted towards the more consistent respective ensemble means. This translates to a decreasing rain chance for Tuesday, but still mostly cloudy with POPS to around 50% SE to 20-30% NW. Highs Tuesday in the low 80s inland, upper 70s to low 80s along the coast. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... TD2 is progged to linger in the vicinity of the NC coast Wednesday and Thursday. There was some agreement in the earlier model runs, but the 28/12z ECWMF lifts the low center farther north off the VA coast Wednesday and Thursday. Main impacts from that solution would be better chance for showers/thunderstorms east of Interstate 95, cooler temperatures, and north to northeast winds of 10 to 15 mph. Have stuck with overall model consensus with keeping the low in the vicinity of the NC coast, but have bumped POPS Weds and Thurs up slightly east of Interstate 95. For Wednesday and Thursday, a warm and humid air mass will be in place over the local area with vorticity maxima associated with the mid level features of TD2 providing modest forcing for ascent. Expect generally scattered showers and diurnal thunderstorms. Subsidence between TD2 and an upstream cold front expected to limit showers/thunderstorms over the Piedmont Weds, with better chances Thursday as a warm front lifts northward over the central Appalachians. Highs in the low to mid 80`s and lows in the 60`s. Sky averages Partly Cloudy. Upstream trough and associated cold front reach the Central Appalachians Thursday night, either kicking the low off the coast or weakening the system over the region. Best chance for dry conditions appears to be Thursday night, before POPs ramp back up Friday as the front reaches the local area. Trough progged to deepen over the Ohio Valley Friday and Friday night, with the front slowing as it reaches the coast. Will keep 30-40% POPs into the weekend as unsettled conditions linger. Highs in the low to mid 80s Friday before cooling into the upper 70s to around 80. Lows in the 60`s. Sky averages partly cloudy to mostly cloudy. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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Generally VFR conditions will prevail for the next few hours until either fog develops north (KSBY/KRIC) or rain moves into the area south (KECG) with sct-bkn stratus around 800-1500ft agl developing in between (KORF/KPHF). Sfc high pressure across the nrn Mid Atlantic Region slowly erodes through the morning as Tropical Storm Bonnie tracks nnw twd the SC coast. Precip chances will be increasing through the day from south to north as wraparound rain bands from TS Bonnie move into the area. MVFR cigs and visibilities should be anticipated, especially as more steady rain overspreads the region late tonight into Mon. Thunderstorms will also be possible this aftn/evening and Mon aftn/evening with periods of moderate to heavy rainfall and additional reductions to cigs and visibilities. A low pressure system tracking ewd above the Great Lakes in Canada is expected to drag a cold front through the region Mon aftn/evening and collect the initial batch of tropical rainfall, thus pushing it offshore by either late Mon night or Tue morning. However the weakening tropical system low pressure is expected to linger invof the Carolina coast through the middle of the week and keep rain chances in the forecast during this time. In addition, areas of fog and prolonged periods of low stratus at all TAF sites should be anticipated Mon night through Thu due to persistent onshore winds, ample tropical moisture present and no discernible weather features to kick the tropical system out to sea until a cold front approaches the region on Thu. This front is expected to cross the area on Fri.
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&& .MARINE... Latest surface analysis centers TD2 roughly 150 miles southeast of Charleston SC. High pressure remains over the western Atlantic, extending over the local waters. Obs indicate south to southeast winds of 10-15 kt over the waters. Waves 1-2 ft and seas 2 to 3 ft. TD2 is expected to strengthen slightly over the Gulf Stream as it lifts northwest toward the SC coast. Impacts for the local waters remain limited to showers and thunderstorms Sunday and Monday. Otherwise, flow will generally be out of the southeast at or below 15 kt. GFS/ECMWF lifts a wave of low pressure along a weak coastal boundary off the Mid-Atlantic coast Monday with light (possibly offshore) flow behind the wave. Seas may reach 5 ft in the northern coastal zones late Monday into Monday evening. The main surface low remains in the vicinity of the North Carolina coast, with the ECMWF now lifting the center of the low off the Virginia coast by Wednesday. Flow expected to be onshore at or below 15 kt, but if the ECMWF verifies SCA conditions will be possible Wednesday and Thursday. Gusts to 25 kt and high seas. Forecast reflects persistence and general model consensus. A cold front is forecast to reach the waters late in the week into next weekend. Sub-SCA conditions expected. For more information on TD2, please refer to NHC. && .CLIMATE... The monthly rainfall total to date for May at Richmond is 8.41". May 2016 is currently the 6th wettest month of May on record at Richmond. There is a good chance for additional rain Sun/Mon with the potential to end as the wettest May on record. Top 6 wettest months of May at Richmond 1. 9.13" 1889 2. 8.98" 1873 3. 8.87" 1972 4. 8.67" 1886 5. 8.59" 2003 6. 8.41" 2016 (to date) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...LKB NEAR TERM...AJZ/LKB SHORT TERM...LKB/MAM LONG TERM...SAM AVIATION...BMD MARINE...SAM CLIMATE...AKQ is the U.S. government's official web portal to all federal, state and local government web resources and services.