Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
049 FXUS62 KGSP 120556 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 156 AM EDT Sat Sep 12 2026 .WHAT HAS CHANGED... No significant changes to the forecast. && .KEY MESSAGES... 1. Not as hot today with more showers and thunderstorms. Heat returns Sunday with isolated mountain convection. 2. A backdoor cold front pushes through the area late Monday keeping dry but still warm weather over the area through much of next week, excluding daily mountain showers/storms. && .DISCUSSION... Key message 1: Not as hot today with more showers and thunderstorms. Heat returns Sunday with isolated mountain convection. A shortwave moves over the area late today while a low pressure wave develops along the stalled frontal boundary over the the area. Deep moisture increases ahead of these features. The atmosphere will be weakly unstable as well. The combination of these features will create numerous showers and thunderstorms. Given the weak instability, the severe storm threat will be low but not zero. Isolated heavy rainfall will be possible given the increase in PW values and storm coverage. Highs will be near to slightly above normal. Drying takes place in the wake of the shortwave. Highs rise back to above normal with highs around 90 across much of the area outside of the mountains. There will be enough lingering moisture and instability for isolated diurnal convection across the mountains. Key message 2: A backdoor cold front pushes through the area late Monday keeping dry but still warm weather over the area through much of next week, excluding daily mountain showers/storms. An upper trough swings across the Great Lakes and into New England Monday. A back door cold front crosses the area late Monday. The front looks to be dry. Highs actually rise a few degrees ahead of the front Monday then drop to near or slightly above normal behind the front Tuesday. A stout upper ridge builds into the area from the west through Wednesday then retrogrades somewhat through the end of the week. This brings temps back above normal into the upper 80s to lower 90s for most locations outside of the mountains. Moisture lingers over the mountains where diurnal convection continues. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: Most of the showers and thunderstorms from this evening have diminished with only leftover cloud debris across the forecast area. VFR mid and high clouds will stick around through the overnight period. Guidance has continued to support lower stratus developing at all TAF sites just before daybreak. Decided to go prevailing SCT IFR and BKN MVFR with a TEMPO for BKN IFR cigs at all TAF sites. Can`t rule out a few instances of fog, especially in the mountain valleys and locations that received heavy rainfall from earlier around daybreak. The low stratus may stick around through the morning hours before slowly lifting and scattering by the afternoon. An earlier onset time for scattered showers and thunderstorms across the terminals so kept either a TEMPO or PROB30 mention for TSRA and associated restrictions. With the scattered coverage of showers and thunderstorms, went with prevailing VCSH rather than SHRA. Guidance hints at another round of low stratus restrictions overnight tonight and hinted at this potential in the last line of the TAFS, especially at KCLT/KHKY/KAVL. Winds will be light and variable overnight and pick up out of the south to southwest at 5-10 kts during the daytime period. Outlook: Scattered afternoon and evening storms will once again be possible Sunday. Storm chances shift to the mountains Monday through much of next week. Mountain valley fog/stratus will be possible any given morning, especially in prone/traditional locations. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ CAC/RWH