Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
121 FXUS62 KCHS 312329 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 729 PM EDT Mon Aug 31 2026 .WHAT HAS CHANGED... All sections have been updated. && .KEY MESSAGES... - 1) Rain chances are in the forecast mid week as an upper level disturbance passes overhead, and again this weekend as a cold front pushes through the region. - 2) Hot and humid conditions return Tuesday and continue into the weekend. && .DISCUSSION... KEY MESSAGE 1: Rain chances are in the forecast mid week as an upper level disturbance passes overhead, and again this weekend as a cold front pushes through the region. Overnight: The focus for nocturnal showers and thunderstorms will once again shift offshore to the coastal waters. We could again see these showers and storms attempt to move toward shore as sunrise approaches, but likely dissipate and fall just short. Otherwise, the forecast is quiet for land areas through the overnight. Rest of this Week: Mid-level ridging will dominate over the southeastern states through the remainder of the week. A mid- level disturbance could approach southeastern GA mid-week, increasing rain chances south of I-16 Wednesday and Thursday. A cold front is forecast to push through the region this weekend, bringing scattered to numerous showers and thunderstorms. KEY MESSAGE 2: Hot and humid conditions return Tuesday and continue into the weekend. Aloft, a ridge of high pressure will extend from the Midwest to the Mid-Atlantic regions early week, beginning a warm-up across the Southeast mid to late week. On Tuesday, the region will start to slide under the eastern periphery of the ridge, bringing widespread temperatures in the upper 80s to lower 90s, with heat index values in the upper 90s to lower 100s. On Wednesday, the ridge axis remains slightly north of the local area with weak h5 vort energy shifting onshore across the Southeast Coast late Wednesday and Thursday, which should maintain similar heat/humidity conditions with slightly higher chances of precip and clouds. Heading into late week a notable increase in ridging occurs aloft, supporting warmer temps into the mid 90s Friday and Saturday. These temps in combination with mid-upper 70 dewpts could possibly support Heat Advisory conditions across the coastal corridor this weekend, before a cold front arrives early next week. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... The 00z TAF period begins with VFR conditions at KCHS, KJZI, and KSAV. The main forecast concern revolves around the potential for low stratus to develop late tonight and right around sunrise Tuesday. There are mixed signals in model guidance with some sources being rather aggressive in the coverage of IFR ceilings and others depicting considerably less coverage. Overall, the best chance to see a short period of IFR stratus looks to be at KSAV. However confidence isn`t particularly high so we have kept the forecast VFR for now. Any stratus that does develop should dissipate quickly after sunrise as surface heating and mixing commences. The potential for afternoon and evening showers and thunderstorms look low overall for Tuesday so we have not included any mention at this time. Extended Aviation Outlook: Showers and thunderstorms could bring brief flight restrictions Wednesday, mainly at the SAV terminal. Greater chances for flight restrictions associated with showers and thunderstorms arrive late Wednesday and Thursday at all terminals (especially SAV) with weak coastal troughing and mid-lvl energy passing nearby. && .MARINE... Through Tonight: Benign conditions across the marine waters through the remainder of today, with SE winds around 10 knots this afternoon shifting to the NE by Tuesday morning. Seas are forecast to average 2 to 3 ft. Tuesday through Saturday: Conditions are expected to remain well below Small Craft Advisory levels this week with light onshore flow becoming slightly enhanced (10-15 kt) along the coast as daily sea breezes develop, then shift inland. Seas will slowly build to 3-4 ft through Wednesday, then slowly subside to 2-3 ft during the second half of the week. Thunderstorm chances could also increase across local waters mid-week (late Wednesday and Thursday) with sfc troughing and h5 vort energy shifting onshore along the Southeast Coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$