Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 271828 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 228 PM 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 1042 AM Saturday... 12Z upper air analysis along with the 14Z meso analysis suggest that best chance for scattered convection this afternoon across roughly the south half of our forecast area. A mid/upper level anti-cyclone positioned to our north will maintain a deep ely flow over our region with the best moisture confluence across the sandhills and the southern piedmont. While the atmosphere will be slight- moderately unstable across the northeast piedmont/northern coastal plain, difficult to discern any mechanism to initiate lift, aside from strong heating. Even across the southern counties, little if any support discernible aloft to initiate/sustain convection. Thus, appears we will need to rely on orographic lift and residual outflow boundaries from previous days convection along with strong heating to initiate lift. With the meso analysis depicting the best moisture axis residing across our southern and western counties, should see the greatest concentration of convection in this part of the forecast area (though no worse than scattered (30-40 percent)). A few strong storms possible with the main hazard being strong gusty winds ~40-45kts and frequent lightning. This has been addresses in the latest HWO product. Afternoon temps in track to reach the low-mid 90s. Counting on some cloud build up/scattered convection to moderate temps a little this afternoon. If this does not occur, places such as Fayetteville and Laurinburg may reach the upper 90s. Afternoon heat index values expected to vary from 98-102 degrees across the north and 102-105 degrees across the south. Do not plan an advisory at this time but will continue to monitor. What convection is occurring at 6 PM will quickly diminish/dissipate around sunset. Under clear-partly cloudy skies, overnight temps will lower into the low-mid 70s. && .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 SATURDAY/...
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As of 226 PM SATURDAY... Monday through Wednesday: The models still indicate a mid- to upper- level low over the western Atlantic will move westward along the southern periphery of the high from Bermuda to the east coast of the U.S. through early next week. The high will weaken as the low approaches and stalls along the Carolina coast through Wednesday. At the surface, some weak ridging lingers over western NC as the low sits just off the coast. Surface winds will be primarily northeasterly. Chances for showers and storms should remain limited to the southern and southeastern portions of Central NC. Highs will be in the mid 80s to around 90 degrees and lows in the upper 60s to low 70s expected. Thursday through Saturday: An upper level trough will amplify over the eastern U.S. Wednesday night and Thursday, when it`s expected to absorb the stalled coastal low. The trough axis should then shift offshore late in the week. At the surface, a cold front is forecast to slide southward into Central NC Thursday night or Friday, although the extent of southward progression is still fairly uncertain. Highest confidence of frontal passage in the northeast and lowest in the southwest. As a result, best chances for convection will be with the front as it moves into and stalls over the Carolinas, though that will also depend on the diurnal timing. The temperature forecast gets a bit more difficult with the aforementioned front, but for now expect a decrease in highs from near 90 degrees on Thursday into the mid 80s Friday and Saturday with lows generally in the mid 60s to low 70s.
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&& .AVIATION /18Z SATURDAY THROUGH THURSDAY/... As of 1255 PM Saturday... There is high confidence that VFR conditions will prevail across central NC through Sunday night. The exception will be isolated- scattered showers and storms through 00Z and associated MVFR ceilings and visibility. The stronger storms will also be accompanied by gusty sfc winds up to 40kts. The scattered convection will be most probable near KFAY between 18Z-22Z...and near and south of the Triad terminals between 20Z and 00Z. The bulk of convection will dissipate with loss of heating, though a shower threat will linger until midnight south of the Triad. After 04Z, should see pockets of low clouds develop and eventually overspread most of central NC with IFR/LIFR ceilings highly probable at most TAF sites between 09Z-14Z Sunday. VFR conditions expected to prevail by 16Z Sunday. VFR conditions are expected to prevail across central NC through most of the upcoming work week. There will be a good chance for early morning IFR/low end MVFR conditions each day due to low clouds and/or fog. In addition, there will be scattered showers and storms each afternoon, with the highest concentration expected in the vicinity of KFAY. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BS NEAR TERM...WSS SHORT TERM...BS LONG TERM...KC AVIATION...WSS

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