Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 170201 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 1000 PM EDT Wed Aug 16 2017 .SYNOPSIS... A surface trough will extend along the North Carolina coast southwestward into central South Carolina and Georgia through Thursday. A back door cold front will approach the region on Thursday before another cold front approaches from the northwest on Friday and moves into the region on Saturday. && .NEAR TERM /OVERNIGHT/...
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As of 1000 PM Wednesday... Little adjustment required to the near term forecast. An isolated heavy rain shower dumped over 2 inches in an hour over north central Guilford, per observation from CoCoRAHS report. This particular cell seemed to be feeding along a tight low level moisture gradient while the lack of overall movement due to relatively weak flow below 500mb. This cell also aided by a weak perturbation aloft drifting sewd across the piedmont. This heavy shower has greatly diminished in intensity since 0120Z. Other isolated heavy showers over the southern Piedmont exhibiting the same characteristics, demonstrating a weakening trend since 0120Z. Through 05Z, cannot rule out an isolated shower as the small perturbation aloft continues to drift sewd, exiting our region after midnight. Overnight, areas of low clouds and fog appear highly probable over central NC thanks to the tropical-like air mass in place. Min temps in the low-mid 70s.
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&& .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 300 PM Wednesday... A short wave ridge axis over the Carolinas on Thursday morning will give way to decreasing heights and an increasing southwesterly flow on Thursday night. An increasing southerly flow will develop allowing a recovery of moisture with precipitable water values climbing back to between 2.0 to 2.25 inches by Thursday evening. While the forcing for ascent is modest, the return of warm advection and increasing moisture should result in an uptick in showers and thunderstorms over today. After a period of morning stratus in the Coastal Plain and northeast Piedmont, expect variably cloudy skies. Low-level thickness values increase a few meters supporting highs between 89 to 94 with lows in the lower to mid 70s. -Blaes && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 335 PM Wednesday... The cold front that`s currently moving across the Central Plains is progged to move across the Appalachians early Friday and across central NC late Friday or Friday evening. This feature and its assoc upper short wave trough will provide the support for scattered showers/tstms Friday and Friday evening. Like fronts often do this time of year when the upper trough pulls out, Friday night`s front will slow down and stall across eastern NC overnight into Saturday morning, and prolong the chance for scattered showers/tstms from about I-95 eastward. Locations west of Raleigh to the Triad should remain dry most of the daytime Saturday. Then another short wave trough and it`s cold front will move across the Mid Atlantic and Carolinas Saturday night into Sunday morning, thus additional wdly sct showers are possible during that time. Given the fast flow to our north, the short wave will exit to our northeast while leaving the sfc cold front stalled across the Carolinas late Sunday into Monday morning, before the front dissipates later Monday. Unfortunately, this may set the stage additional showers on Monday, and with a fair amount of cloudiness around, possibly obscuring the partial eclipse Monday afternoon. I wouldn`t give up hope just yet for seeing the partial eclipse here in central NC, as there is a fair amount of disagreement among models regarding how far south the front will stall, and thus where the best chance for clouds and showers will be. Stay tuned! At or above-climo rain chances will continue Tue and Wed thanks to cyclonic flow and a series of short waves crossing the region. Temps during the long term period at or above normal. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... As of 830 PM Wednesday... 24 Hour TAF Period: VFR conditions are expected to continue this evening, outside of any isolated showers through around 02Z (KGSO and KINT, possibly at KFAY). Another round of late night stratus and/or fog will be possible again tonight, mainly across eastern portions of the area, where we could see IFR/LIFR conditions (best chance at KFAY/KRWI). We may see a morphing of the low stratus/fog and moist low level conditions into some stratocumulus, yielding a period of MVFR cigs in the 13-17Z time frame, before lifting and scattering. Scattered showers and storms are expected to develop Thursday afternoon/evening across the entire area, with the main threat of heavy rain and lighting, yielding sub-VFR conditions. Outlook: A cold front will approach the region on Thursday into Friday and then settle across the area on Sunday into Monday. This result in an increase shower and thunderstorms, primarily during the afternoon and evening on Thursday into Saturday with a decrease in adverse aviation conditions on Sunday into Monday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BLAES NEAR TERM...WSS SHORT TERM...BLAES LONG AVIATION...BSD/BLAES is the U.S. government's official web portal to all federal, state and local government web resources and services.