Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
835 FXUS62 KGSP 291731 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 131 PM EDT Fri Aug 29 2025 .SYNOPSIS... High pressure remains before a weak cold front crosses the area Saturday, keeping the cooler weather in place. A brief shower or thunderstorm possible each day across the mountains. Temperatures remain below seasonal normals through the week. && .NEAR TERM /THROUGH SATURDAY/... As of 130 pm Friday: Anomalous upper trough will remain centered over the region through the near term, reinforced by a series of speed maxima digging southeast from the upper Miss Valley and the Ohio Valley tonight. These height falls are forecast to result in weak activation of the quasi-stationary baroclinic zone over the Southeast late tonight into Saturday. By far the highest associated precip chances across the region will be south of our forecast area, but enough of a signal exists to advertise small PoPs across southern areas throughout the day. Farther north of there...decent insolation and steadily increasing low level moisture is expected to result in modest destabilization Sat afternoon, with increased potential for diurnal convection (mainly showers) across the mountains. Even so, PoPs are 30% at most. Otherwise, quiet conditions tonight with another round of fog/low stratus likely in the valleys of the NC counties bordering TN. Min temps are expected to remain a few degrees below climo. Maxes Saturday are expected to range from 5+ degrees below normal under thicker cloud cover across the Lakelands and vicinity...to slightly below normal across much of western NC. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 125 PM EDT Friday: Picking up on Saturday night, a persistent ridge out west and trough over the eastern CONUS remain the dominant synoptic feature driving the cooler weather across the CWA. A strong upper low over Canada lifts northward while the trough splits as high pressure forms over the upper Midwest. Guidance tries to spin a cutoff low that sets up over the Mid-Atlantic by Sunday night. Meanwhile, guidance increases moisture a bit through the period, but nothing quite as miserable as the past few summer months. A few shortwaves come through and with the uptick in PWATs, increases rain chances, especially across the mountains. Current PoPs at the higher peaks are in the chance range (50-65%) with slight chance (15-30%) for the rest of the mountains and portions elsewhere. For Sunday, upper air guidance shows some elevated and surface based instability during the afternoon hours, so cannot rule out a rumble of thunder. Probability of thunder for Sunday is hovering around slight chance (15-30%). Temperatures start to trend cooler into the beginning of the week. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 130 PM EDT Friday: The pattern remains relatively quiet through the extended. By Monday night, the flow aloft becomes more broad. At the surface, guidance slowly increases the moisture in the southern zones, but keeps it modest. Long range guidance does have a strong signal for yet another upper low developing over Canada with a strengthening trough digging across the eastern CONUS. This is expected to continue the cooling trend as winds become NW and drier air filters in. There could also be a midweek cold front that passes through as well as a few shortwaves with the NW setup. Daily precip chances (20-45%), especially across the mountains. Winds could become a bit gustier, depending on how far south the trough digs and how tight the pressure gradient becomes. Nothing too concerning at this time and will continue to monitor. Temperatures remain just below average during the extended period. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: Other than the expected redevelopment of early morning mountain valley fog/low stratus in areas to the west and north of KAVL, VFR conditions are expected through tomorrow. Some cu/stratocu in the 050-070 range is expected to develop later today, continuing off and on through tonight. Some spotty showers will be possible across the mountains and southern portion of the Terminal Forecast Area during the daylight hours Saturday, but the chances are too low for a TAF mention at this time. Winds are generally expected to be light (except for 5-10 kts at KAVL), with direction mostly favoring a northerly component through the period. Outlook: Scattered afternoon, mainly mountain showers and thunderstorms are expected to return early in the new week and continue through at least the middle of the week. Fog and/or low stratus may develop each night/early morning, mainly in the mountain valleys. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CP NEAR TERM...JDL SHORT TERM...CP LONG TERM...CP AVIATION...JDL