Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 280808 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 408 AM EDT SUN AUG 28 2016 .SYNOPSIS...
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High pressure will persist over the region through today. An upper level disturbance over the Atlantic will then drift west along the Carolina coast Monday and Tuesday.
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&& .NEAR TERM /THROUGH TONIGHT/...
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As of 400 AM Sunday... An well defined upper low off the Carolina coast will continue to drift west beneath the 595dm 500mb ridge over the Mid-Atlantic states today, while a surface ridge extends into the area from the Northeast coast. We`re starting to see a little stratus spreading inland across the coastal plain in northeast flow, which will lead to mostly cloudy skies through mid-morning as the stratus slowly burns off. Deeper mixing over the Piedmont may result in dewpoints in the lower 60s, limiting instability and confining the best precip chances tot he coastal plain, where increasing moisture and moderate instability will support scattered storms as the aforementioned upper low approaches the coast and likely enhances convection along the seabreeze. Shear parameters are generally weak, so the main impact from convection will likely be from brief heavy downpours given PW increasing above 2 inches. The CAMs are in pretty agreement in the favored area being from Fayetteville to Goldsboro and to the east. 850mb temps fall from 20C to 18C today, which combined with a little more northeasterly flow and morning cloud cover, should keep highs a few degrees lower than yesterday, 89-92. Convection will generally be diurnally driven today, though the approaching upper low and easterly low-level flow may continue to support some inland moving showers into the overnight hours. Stratus is expected again across the coastal plain by Monday morning, with lows in the upper 60s and lower 70s.
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&& .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
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As of 400 AM Sunday... Monday looks fairly similar to today, with the upper low drifting inland over SC and briefly stalling. A strong moisture gradient will set up again with the surface ridge and deeper mixing in the west, and better moisture/instability over the coastal plain. A weak offshore surface low drifting toward the NC coast will have little impact here, and scattered showers and a few storms will again be confined to the southern coastal plain. Highs in the upper 80s and lower 90s. Lows monday night in the upper 60s and lower 70s. .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 226 PM SATURDAY... WV imagery this morning depicts an increasingly well-defined mid to upper level low off the SERN U.S coast. The forecast models continue to indicate this feature will drift W --around the SRN periphery of the initially strong sub-tropical ridge centered over the Middle Atlantic states-- and stall along the SERN U.S. coast early this week, before shearing out and lifting away from the region through the middle of the week. The presence of this mid-upper low, and a NRN stream trough forecast to migrate across the NERN U.S through early week, will cause the preceding sub-tropical ridge to succumb over the Middle Atlantic states and ultimately split, with one center expected to retrogress into the central U.S. and the other retreat into the central N. Atlantic Ocean. A broad trough will develop between the two /over ERN U.S./ through the end of the week. This pattern aloft will play an important role in what becomes of the now well-advertised tropical wave along the NRN coast of Cuba this morning, which the models now generally agree will enter the ERN Gulf of Mexico early to mid-week. Significant model spread regarding the track and timing of the associated low develops thereafter, though it seems reasonable that low will eventually be influenced by the aforementioned ERN CONUS trough aloft and be drawn NEWD through or along the SERN U.S coast, with an associated increased probability of rain, through the end of the forecast period. Of greater predictability will likely be a NRN stream cold front forecast to settle through the SRN Middle Atlantic states and Carolinas Thu-Fri, with an accompanying chance of convection maximized in central NC Thu-Thu night. Cooler and drier conditions in post-frontal high pressure ridging across the Middle Atlantic region would follow, though the duration of this post-frontal regime will hinge upon what happens with the tropical low and associated moisture potentially approaching from the south later Fri and Sat.
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&& .AVIATION /08Z SUNDAY THROUGH THURSDAY/... As of 200 AM Sunday... Early showers and storms have pushes west through the southern Piedmont and conditions are mostly VFR across the area at 06Z. Skies have mostly cleared across eastern NC, which may lead to some fog after 08z, though northeasterly flow may favor more low clouds than fog, possibly as low as LIFR. Confidence is pretty high that RWI and FAY will see IFR or LIFR conditions by 09z. To the west, RDU may end up right on the end of the low clouds, but sub-VFR vsbys will still be possible at RDU, GSO, and INT given earlier rainfall. If stratus does indeed develop over the coastal plain, models suggest it will be slow to lift through the morning hours, with a period of MVFR ceilings as far west as RDU between 12z and 15z. Scattered storms will likely develop later this afternoon, mainly from FAY to RWI and to the east. Outlook: 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...BS SHORT TERM...BS LONG TERM...MWS AVIATION...BS

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