Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 281409 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1009 AM EDT THU JUL 28 2016 .SYNOPSIS... Broad surface high pressure will linger over the Southeast, while a surface low tracks along a stationary front across the Mid-Atlantic. This front may finally sag south into our area early next week. && .NEAR TERM /THROUGH TONIGHT/...
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As of 10:07 am: Another hot day is underway with only subtle changes to the forecast at the moment. Heat indicies near 105 are still forecast in far eastern zones, supporting the HEAT ADVISORY for that area. Scattered afternoon thunderstorms are also expected, mostly over the mountains, though some CAMs have some very isolated cells over piedmont areas. Short range models indicate that a mid level short wave will slowly ripple east across KY/TN today. Guidance indicates that a band of SHRAs and TSRAs will develop along and ahead of the S/W across eastern KY/TN. Coverage of convection will gradually increase across the southern Appalachians during the mid to later afternoon. Forecast soundings east of the mtns indicate weak capping will remain through the afternoon, limiting coverage to isolated. Deepening sfc low pressure across VA should yield a 2-3 mb pressure gradient across the CWA this afternoon. The combination of afternoon mixing and the shallow gradient should result in a period of marginal gusts from the SW. Moderate instability and weak shear may support a few svr storms. Sunny conditions and llvl downslope winds will result in steady warming through mid day. Given very mild morning low temperatures, noon time temps could easily range in the low 90s east of the mtns. High temperatures are forecast to peak from the upper 80s across the mtn valleys to the mid to upper 90s east. The hottest temperature should exist east of I-77, under 22c H85 temps, with values around 98. Similar to Wednesday, the combination of hot temperatures and RH values 43 to 45 percent should result in Heat Index to peak at or above 105 F. We will issue a Heat Advisory for Davie south the Union. Tonight...I expect that convection will linger across the mtns ahead of the mid level S/W. Schc PoPs will remain across the mtns. Min temps forecast will range around 3 to 5 above normal.
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&& .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 300 AM Thursday...There will be little change in the pattern for Friday and Saturday. A weak and shallow trough will continue to produce a weakness in the subtropical high over the lower to mid-Mississippi Valley. A surface wave will pass east of the area by Friday morning, and the low-level flow will take on a more west to west-southwest direction. This will result in some downslope influence east of the mountains. Despite this, models show a continued gradual decreasing trend in low-level thicknesses. Highs will still by about 3-5 degrees above normal both days. Convection will continue to favor the mountains, as usual. The downslope may limit Piedmont convection. On Friday, most of the operational models show a lack of convective response with the Piedmont/Lee trough. But with a westerly steering flow, some of the mountain convection should push off to the east. Saturday`s PoPs look a little higher, as moisture increases ahead of another wave streaking through the Ohio Valley. Overall, lack of shear and forcing should result in continued pulse mode with an isolated microburst threat. Dew points should mix out enough to preclude any heat index headlines, but HI`s will continue to be in the upper 90s to around 104, both afternoons. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 315 AM Thursday...The weakness in the upper-level subtropical ridge will gradually drift east from the Mississippi Valley to the East Coast by Tuesday. A quasi-stationary front will gradually sag south into the area Monday into Tuesday and gradually wash out Wednesday. So the medium range forecast will feature slightly above climo PoPs and temps about a category above normal. This pattern will hopefully provide more widespread rain to ease the drought. && .AVIATION /14Z THURSDAY THROUGH MONDAY/...
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At KCLT and elsewhere: Short range models indicate that a mid level short wave will slowly ripple east across KY/TN today. Guidance indicates that a band of SHRAs and TSRAs will develop along and ahead of the S/W across eastern KY/TN. Coverage of convection will gradually increase across the southern Appalachians during the mid to later afternoon. Forecast soundings east of the mtns indicate weak capping will remain through the afternoon, limiting coverage to isolated. Deepening sfc low pressure across VA should yield a 2-3 mb pressure gradient across the CWA this afternoon. The combination of afternoon mixing and the shallow gradient should result in a period of marginal gusts from the SW. KAVL may see MVFR up valley stratus develop late tonight, mainly after 8z. Outlook: Falling heights aloft and the arrival of gulf moisture will support increasing chances of precipitation and perhaps associated restrictions going into the weekend. Confidence Table... 14-20Z 20-02Z 02-08Z 08-12Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 100% High 100% Med 70% KHKY High 88% High 100% High 100% High 100% KGMU High 100% High 100% High 100% High 100% KAND Med 66% High 100% High 88% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: www.weather.gov/gsp/aviation
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&& .GSP WATCHES/WARNINGS/ADVISORIES...
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GA...None. NC...Heat Advisory until 8 PM EDT this evening for NCZ037-057-072- 082. SC...None.
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&& $$ SYNOPSIS...ARK NEAR TERM...NED/WJM SHORT TERM...ARK LONG TERM...ARK AVIATION...NED

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