Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
758 FXUS62 KGSP 031746 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 146 PM EDT Fri Oct 3 2025 .SYNOPSIS... High pressure continues to dominate the forecast the next few days, while temperatures slowly warm up through the weekend. Moisture returns early in the new workweek, causing clouds and rain chances to increase through Wednesday, when a cold front arrives. && .NEAR TERM /THROUGH SATURDAY/... As of 1154 AM Friday: Broad upper ridging remains in place from the Mississippi Valley to the Ohio Valley and points south/east as a compact shortwave trough lifts out of the Great Basin and towards the central and northern Great Plains. At the surface, high pressure continues to migrate down the east coast and is forecast to become centered just off the Mid-Atlantic coast through tomorrow. This will continue to keep a very quiet forecast in place for the area with very pleasant weather. Gradual airmass modification will continue through the period with overnight lows tonight and afternoon highs tomorrow a couple ticks above what was observed this morning/afternoon. High-level clouds will increase in coverage overnight through tomorrow in association with a reservoir of high- level moisture over the southeast states, the only impacts of which will be the potential for perhaps a colorful sunset/sunrise. Otherwise, shallow moisture pooling in favored mountain valleys should once again support another bout of early morning valley fog, some of which could be locally dense. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 1153 AM EDT Friday: Classical CAD will be in place by Sunday as high pressure centered over Long Island and Connecticut ridges down the east coast. Little if any precipitation is expected Sunday...as forecast soundings depict a dry environment and only weak isentropic ascent over most of the area through Sunday evening. Extensive cloud cover, however, is still expected within the upglide layer, though during the afternoon some areas could mix out enough to see some sun. Highs should climb into the upper 70s or lower 80s across the low terrain. Lows Sunday night will fall into the lower 60s, or even the upper 50s along the I-40 corridor. By Monday, the surface high will draw farther and farther away from the Eastern Seaboard, severely reducing the synoptic support for CAD...such that somewhat better chances for mixing out low clouds are expected on Monday. Still not carrying a PoP for Monday...but operational guidance hints at a slug of better isentropic ascent developing Monday evening, which if enough moisture advects in within this layer could result in some isolated sprinkles. Highs on Monday will be similar to Sunday, maybe a degree warmer, especially if the afternoon is less cloudy. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... As of 1229 PM EDT Friday: By Monday night, z500 ridging that once dominated the Southeast will be increasingly "smushed" in response to a broad confluent zone stretching from the Four Corners region of the American Southwest all the way to the Great Lakes and south-central Canada. Successive shortwaves on Tuesday and Wednesday will lead to the complete breakdown of the ridge, before they phase together mid-week to form a single potent trough over New England. The result will be lingering CAD on Tuesday, with some potential for more widespread drizzle as another slug of stronger upglide develops...and then a cold front on Wednesday. There`s still decent ensemble variability with this front, but the latest LREF cycle generally agrees there`ll be at least a wetting rain for most locations, but disagree on whether there will be much/any potential for convection to enhance rates. Some members depict at least a few hundred Joules of instability developing ahead of the front, while others predict it`ll simply be too dry and cool for good instability to develop. Regardless, high pressure should build in behind the front, persisting through the end of the period. Temperatures will remain a category or so above normal through Wednesday, before falling well below normal (with pleasant highs in the low 70s) behind the front Thursday and Friday. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: VFR conditions will prevail at most terminals through the TAF period. Quiet conditions will continue through the rest of today and into tonight with a gradual uptick in high-level clouds. Another round of mountain valley fog/stratus will be possible early tomorrow morning at KAVL with the potential for respective impacts to visibility and ceiling. Any fog should quickly mix out after sunrise with a return to VFR area wide. Winds will remain light out of the northeast with calm winds overnight. Outlook: Dry high pressure and VFR conditions expected across the terminals through the weekend, outside of mountain valley fog/low stratus each morning. Rain chances, and possibly restrictions, return early next week. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...MPR NEAR TERM...TW SHORT TERM...MPR LONG TERM...MPR AVIATION...TW