Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
834 FXUS62 KGSP 041041 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 641 AM EDT Sun Oct 4 2026 .WHAT HAS CHANGED... Precip probabilities for this morning have decreased. Aviation discussion has been updated for the 12Z TAF issuance. && .KEY MESSAGES... 1. Cloudy and much cooler today for most locations, with areas of mostly light rain/drizzle possible, mainly this afternoon and evening. 2. Near-normal temperatures and dry conditions are expected for much of the work week, with little chance for precipitation. && .DISCUSSION... Key message 1: Cloudy and much cooler today for most locations, with areas of mostly light rain/drizzle possible, mainly this afternoon and evening. The leading edge of a backdoor cold front has settled south of the CWA this morning, with in-situ cold air damming/notably cooler/more stable air having overtaken all but the upper Savannah Valley. Showers have largely vacated the scene as a result, taking any excessive rainfall threat along with them. Cool/stable air will encompass virtually the entire CWA through tonight...locations across the Smokies and vicinity being a somewhat notable exception for this afternoon. Max temps are forecast to be almost 10 degrees below climo in most areas outside the mountains...more like 0-5 degrees below normal across the higher terrain. Conditions will remain very moist, with precipitable water values AOA 1.75" expected to linger through the day. A low amplitude trough and associated entrance region of an upper jet will approach the region this afternoon, resulting in some increase in upward vertical motion. However, low level flow/forcing is expected to remain weak as pressures fall within in situ cold air damming region, such that little to no isentropic lift is expected. If anything, the flow above the surface-based stable layer is more downslope/WNW through a good chunk of the day. While chances of rain/drizzle should ramp up to the solid chance/likely range this afternoon, especially across the southern half of the area, the combination of weak forcing and stable air should preclude redevelopment of an excessive rainfall threat. Thunderstorms are generally not expected, except for the potential for an isolated storm or two across the Smokies. The rain and drizzle will gradually diminish tonight as the upper trough axis shifts east of the area and significant mid/upper level drying occurs. Lingering low level moisture within residual in situ cool pool beneath this drying aloft will yield some potential for (at least) locally dense fog late tonight/early Monday. Key message 2: Near-normal temperatures and dry conditions are expected for much of the work week, with little chance for precipitation. In the wake of a departing upper trough, continental high pressure will steadily build into the region from the northwest early in the work week, with steady deep-layer drying expected to bring a return of mostly sunny conditions on Monday. This allow max temps to warm very close to climo during the afternoon. As the center of surface high pressure settles over the central Appalachians and Mid-Atlantic Mon night/Tue, temps are forecast to fall to around 5 degrees below climo before rebounding to near-normal levels as the surface high moves off the East Coast during mid-week. Temps are forecast to remain within a couple of degrees of normal through at least Friday. General weak surface ridging is expected to remain in place over the region through the end of the week, so conditions will remain dry and humidity relatively low. Global models are in general agreement that a southern stream disturbance will lift out across the lower Miss Valley next weekend, bringing more cloud cover, small PoPs and slightly cooler temperatures by Saturday. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... At KCLT and elsewhere: A wedge of stable air has infiltrated the Terminal Forecast Area this morning, and this has brought an end to much of the scattered convective activity. Most locations are reporting IFR cigs, with some areas of LIFR or low MVFR also noted. At least tempo IFR/LIFR cigs (and MVFR visby) are expected to persist through the morning, with improvement to MVFR expected during the early afternoon, with VFR becoming likely by late afternoon. The approach of an upper trough may bring a return of areas of mostly -RA/possible DZ...especially to the southern half of the area by late afternoon/evening. This will increase the potential for reduced visby along with a return of restricted cigs. Having said that, chances for precip at any terminal are such that only Prob30s are warranted for now. Cigs will begin to return to IFR or lower by late this evening, with increased potential for fog as conditions dry aloft, but the low levels remain very moist. Overnight visby is mainly advertised in the 2-3SM range for now, but the potential is there for lower visby. Winds will remain NE 5-10 kt at most sites (light/vrbl at KAVL), becoming light/variable at all locations during the afternoon...continuing through the period. Outlook: Improvement to VFR is expected in most areas by late Monday morning. Dry VFR conditions are then expected to persist through the rest of the week...except for the potential for morning valley fog/low stratus. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ JDL