Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 281743 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 143 PM EDT SAT MAY 28 2016 .SYNOPSIS... High pressure will push farther off the Mid Atlantic coast through tonight. Low pressure northwest of the Bahamas will move toward the South Carolina coast today and tonight, and will linger along the coastal Carolinas through the holiday weekend. && .NEAR TERM /THROUGH TONIGHT/... Late morning analysis reveals 1024+mb surface high pressure well off the VA/NC Coast, ridging back toward the Mid- Atlantic/Carolina piedmont. To our southeast, weak sfc low pressure (still TD #2 as of 11am NHC position update) is located about 200 mi SSE of Charleston SC. Aloft, strong upper level ridge centered offshore is similarly ridging back west into VA. The upper ridge looks to be slow to retreat/weaken over the region out ahead of the advancing sub-tropical low. Models continue to depict a large zone of subsidence over the local area through this aftn. Current obs and satellite trends show driest low level airmass/best subsidence located over southern VA where dew pts are into the upper 50s, with higher dew pts into the mid 60s over NE NC and also acrs northern zones. SCT/BKN Cu already developing in ne NC, but do not anticipate this to develop into anything more than perhaps an isolated shower by late aftn due to the subsidence from the ridging aloft. Thus, will be keeping the vast majority of the forecast area dry through the afternoon/early evening, will maintain just a slight chc/20% pop across interior ne NC counties due to diurnal instability and increasing moisture (PW values increase to about 1.50" by late afternoon and early evening). Highs in the mid to upper 80s inland/piedmont areas (warmest highs approaching 90 F in the far NW), and in the upper 70s to lwr 80s along the coast. Models remain in good agreement with showing upper ridge buckling e-ne tonight, with TD#2, or quite possibly Tropical Storm Bonnie by that point, approaching the se coast. PW values AOA 2" expected to push across the area after midnight/Sunday morning. GFS remains most aggressive with northward expansion of POP, with the remainder of CAMs and probabilistic guidance in decent agreement in trending pops upward from south to north late tonight into Sunday morning. 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 /SUNDAY 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 the period. Refer to discussions issued by the National Hurricane Center for the official track and forecast. Have nudged pops upward Sunday, with unsettled conditions continuing w/warm and quite humid airmass in place. Highest POPS look to shift just inland from the coast by aftn, as h7 WAA/Omega and upper jet dynamics (RRQ) favor likely pops, which could well be focused along inverted sfc trough that will be oriented from the piedmont into the Lower Eastern Shore of MD. Accordingly expect to see numerous periods of rain, falling moderate to heavy at times. Highs on Sun generally in the upper 70s to lwr 80s. 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. Potentially very wet conds persist, with occasional moderate to heavy showers expected from time to time in the modified tropical airmass. Will continue high chc to likely POPS Sun night/Mon, with high end likely pop lingering into Monday morning along the Northern Neck and Eastern Shore. Warm and humid with early morning lows 65-70 F Monday morning and highs in the upper 70s/lower 80s on Memorial Day. A bit of disagreement amongst deterministic models by Tuesday, with the 00z/Operational GFS wanting to dry us out under developing weak sfc ridging, but curiously lingering the main upper system along the coast. Meanwhile, the ECMWF is a bit quicker to clear out the low altogether, ejecting it quicker to the NE. Followed a WPC blended solution, weighted towards the more consistent respective ensemble means. This translates to a steadily decreasing rain chance for Tuesday. However, will still carry a solid chance pop along the coastal plain, and a slight chc inland. Highs Tuesday in the low to mid 80s inland, upper 70s to low 80s along the coast. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... Unsettled weather conditions continue into the extended period as the remnant tropical depression (per NHC latest forecast) lingers over the Carolinas or near the Carolina coast Tuesday. Deepest moisture gets pushed offshore Tuesday as upper level energy lifts over the southeast local area. Will keep mention 30-50% POPS over the southeast half of the local area with only slight chance northeast half. The low weakens into Wednesday with an inverted trough/coastal front locating along the Mid-Atlantic coast. Lingering moisture along the coast will result in only chance POPs northeast North Carolina and southeast Virginia. Dry conditions expected Wednesday night with a partly cloudy sky. An upstream trough approaches the region Thursday as upper level ridging remains over the western Atlantic. An associated cold front is forecast to reach the Ohio Valley early Thursday. Amplifying flow will lift the frontal boundary northward with increasing chances for showers and thunderstorms over the Piedmont and northeast North Carolina Thursday. Meanwhile, the remnant low pressure is expected to weaken off the Southeast/Mid-Atlantic coasts. Forecast confidence decreases toward the end of the week and into the weekend as the cold front approaches the region. The preference at this time is to stick with the ECMWF, which pushes the front across the region Friday. Unsettled conditions expected to persist into the weekend as the front likely stalls along the coast. Temperatures forecast generally around seasonable norms during the period. Highs low to mid 80`s with lows in the 60`s. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR conditions should continue through this afternoon into this evening as high pressure remains in control with a dry airmass across the area. As Tropical Depression Two moves toward the South Carolina Coast, tropical low level moisture will move northward and surge off the Atlantic and into the region later tonight into Sunday. This will allow for IFR cigs to spread across the area late tonight. Higher low level dewpoints may allow for some ifr vsbys overnight as well. On Sunday, rain will spread from south to north during the day. In turn...cigs/vsbys will likely raise to mvfr Sunday morning. Outlook...Despite the depression forecast to dissipate to a remnant low, the guidance suggests that the tropical moisture will persist across the area for much of the week. As such...expect plenty of shower activity through the week esepcially across far south VA and NE NC. Expect many periods of VFR through the week, however with the moist airmass in place, there will be periods of MVFR or IFR conditions through much of the week, especially in the overnight and early morning hours. && .MARINE... No major impacts related to Tropical Depression Two anticipated. High pressure resides over the Mid Atlantic Region today and is not expected to break down until later this evening. South winds become more se by this aftn as Tropical Depression Two slowly moves into the Southeast coast. Isolated showers and thunderstorms could develop over srn Currituck Sound on seabreeze boundaries this aftn/evening, but confidence is low. General trend is for wraparound precip from the tropical system to move into the waters from south to north late tonight through Sun...becoming more persistently widespread over the waters Sun night through Tue morning. Thunderstorms will be possible Sun-Mon evening. Although the pressure gradient tightens over the waters as the tropical low meanders over the Carolinas, se-s winds remain fairly steady aob 15kt throughout the duration of this system. Seas generally 2-3ft today...building to 3-4ft srn waters Sun...then all waters by Sun evening through Mon night. Waves 1-2ft today...building to 2-3ft srn Ches Bay during Sun only. Waves may stay elevated around 3ft in the mouth of Ches Bay due to persistent onshore swell through Mon. 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 remnants of the weakening tropical system, thus pushing all rain offshore by either late Mon night or Tue morning. Areas of fog may be possible over the waters Mon night/Tue morning as high pressure starts to build back into the region. A brief period of north winds are possible Tue morning, but will turn around to an e-se direction by Tue aftn. Seas subside to 2-3ft/waves 1-2ft on Tue. Low stratus and periods of fog may linger over the waters Tue-Thu due to ample moisture present, persistent onshore winds, and no discernible weather features present to mix out the lower atmosphere. The next more well-defined cold front is expected to cross the waters late in the upcoming week. && .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...MAM NEAR TERM...LKB/MAM SHORT TERM...LKB/MAM LONG TERM...SAM AVIATION...MRD MARINE...SAM CLIMATE...

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