Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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270 FXUS62 KRAH 270752 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 352 AM EDT SAT AUG 27 2016 .SYNOPSIS... An upper level ridge will persist over the region through the weekend. An upper level disturbance over the Atlantic will then drift west and linger over the Southeast states early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 350 AM Saturday... The 595dm ridge at 500mb is centered eastern KY last evening has shifted over VA, per latest RAP analysis. Meanwhile, a weak low- level trough, evident at 925mb in regional VAD wind profiles, is slipping into the northern coastal plain and will washout today as east-northeasterly flow sets in over the CWA. There is little other evidence of the trough, and the few showers the HRRR was showing popping around Halifax/Edgecombe/Nash counties have yet to materialize, and probably won`t. Diurnal convection should fire by early afternoon, however, as moist easterly flow and a slight reduction in 850mb temps help weaken the CAP over NV, resulting in 1000-1500 j/kg MLCAPE. Forcing is otherwise very weak, and the CAMs favor development in the southern Piedmont/coastal plain, drifting southwest with time. With the core of the 850mb thermal ridge still northwest of the Piedmont and mixing fairly similar to yesterday, temps should be within a 2 or 3 degrees of yesterdays highs in many spots tempered slightly by the easterly flow; 92-96. This will keep conditions rather humid, but heat indices should stay below 105. Diurnally driven convection will die off this evening, yielding to mostly clear conditions for the first half of the night and increasing probability of stratus in easterly flow over the coastal plain. lows 70-74. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 350 AM Saturday... The upper level ridge will continue a northward drift on Sunday, while an upper disturbance over the Atlantic slowly drifts west and undercuts the ridge, essentially settling over the Southeast US through early next week. This disturbance along with increasing moisture flux off of the Atlantic - PW increasing to around 2 inches - and weak to moderate instability will likely result in enhanced convective coverage along the coast, drifting inland through the day. Coverage will be best over the coastal plain, diminishing with westward extent into the Piedmont where deeper mixing and drier air will limit coverage. Some of the showers may continue into the evening and overnight hours, mainly across the southern coastal plain. Highs 89-92, warmest west. Lows 69-74. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 310 PM Friday... Medium range models appear to be coming into a bit better agreement on showing the weak tropical low located between the northeastern coast of Cuba and the central Bahamas shifting west-northwestward across FL and into the far eastern Gulf of Mexico/near the western FL coast this weekend into early next week before slowly lifting north and eventually northeastward. However, there is still a lot of uncertainty with regard to the timing of this system and timing of a s/w trough approaching/amplifying in the northern stream mid to late week (which will play a key role in our precip chances mid to late week). Further northward across our latitude, a weak mid/upper level low is forecast to move westward late Sunday into Monday and into eastern portions of the Carolinas. This will provide eastern/southeastern portions of the area with a chance of mostly diurnal showers and storms on at least Monday. The mid level low is forecast to linger across eastern portions of the area on Tuesday, before being suppressed by a approaching northern stream s/w trough. However, with still a significant spread in some of the models and ensembles with regard to the track and timing of the possible tropical system and potential moisture possibly pulled northward and across eastern portions of our area we will keep a chance of showers and storms across eastern portions of the area through midweek. As the northern trough further amplifies and shifts eastward across our area an associated cold front will move through the area on Thursday into Friday (with a possibly some showers and storms areawide accompanying the front). High temps are expected to generally be in the upper 80s to lower 90s, with mid to upper 80s on Friday. Lows are expected to be near 70 to the mid 70s. However, if the track and/or intensity were to change with the aforementioned tropical system, then High temps may be lower midweek. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... As of 205 AM Saturday... VFR conditions will generally rule through the current TAFS period with high pressure aloft over the region. There is a weak and shallow trough that will slip into the area tonight, with northeasterly winds to follow on Saturday. Some hi-res model guidance indicates a few showers could pop up in the coastal plain early this morning, near RWI if they did, but confidence is rather low given no ongoing showers. Otherwise, just some pockets of MVFR vsbys will be possible prior to sunrise. Widely scattered showers and storms are possible this afternoon, though most should develop to the south and west of the TAF sites, and then drift further southwest, limiting the impacts at TAF sites. Long Term: Low rain and thunder chances will prevail for the next several days keeping conditions mostly dry with some isolated to scattered convection during the afternoon hours, particularly across the east. Otherwise mostly VFR conditions are expected. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BS NEAR TERM...BS SHORT TERM...BS LONG TERM...BSD AVIATION...BS is the U.S. government's official web portal to all federal, state and local government web resources and services.