Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
628 FXUS62 KCHS 200033 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 833 PM EDT Sat Sep 19 2026 .WHAT HAS CHANGED... All sections have been updated. && .KEY MESSAGES... - 1) Daily thunderstorms are expected across southeast Georgia and southeast South Carolina this weekend and into early next week. An increase in rain chances is expected by the middle of next week, with cooler temperatures thereafter. && .DISCUSSION... KEY MESSAGE 1: Daily thunderstorms are expected across southeast Georgia and southeast South Carolina this weekend and into early next week. An increase in rain chances is expected by the middle of next week, with cooler temperatures thereafter. Through Tonight: Clusters of showers and thunderstorms continue to develop along/ahead of an outflow boundary shifting south across Southeast Georgia this evening. A stronger thunderstorm or two can not be ruled out prior to this activity departing south of the Altamaha River during the next few hours. However, diurnal heat loss should generally support a weaker trend by late evening hours. Sunday through the middle of the week: Sunday should be similar to Saturday with diurnal convection driven by the sea breeze and coverage in the isolated to scattered range. Monday should also bring about rather modest coverage mainly in the form of diurnal convection. Better convective coverage and higher rain chances are anticipated Tuesday into Wednesday as a front approaches from the north. There could be a threat of locally heavy rainfall during this mid week time period as coverage increases in the presence of precipitable water values in excess of 2 inches. Behind the mid week cold front, noticeably cooler air is expected for the latter part of the week. Highs in the upper 70s to low 80s for southeast SC and low to mid 80s for southeast GA look probable at this time, which would be a few degrees below normal for late September. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... TEMPO MVFR conditions are possible between 00Z-01Z at SAV due to lower vsbys and gusty winds associated with passing showers and/or thunderstorms. Otherwise, VFR conditions should prevail at CHS/JZI/SAV terminals this evening and into early morning hours Sunday. Guidance continues to support MVFR cigs (and possibly vsbys) at all terminals between 10Z-14Z Sunday, with some potential of IFR cigs at CHS/JZI terminals as well during this timeframe. VFR conditions should then return and prevail after 14Z Sunday. However, showers/thunderstorms could impact all terminals late morning into early afternoon hours. PROB30 groups have been added at JZI between 15-19Z Sunday, at CHS between 16-20Z Sunday and at SAV between 17-21Z Sunday. Extended Aviation Outlook: The main potential for sub-VFR conditions will come from afternoon and evening showers and thunderstorms each day. The best chance of showers and thunderstorms is expected to come Tuesday into Wednesday. && .MARINE... Through Tonight: Very quiet conditions will continue across the local waters. Light onshore flow this evening will remain light and turn more northeasterly overnight. Seas are expected to average around 2 ft. A few showers/thunderstorms are possible along the GA coast this evening, potentially producing gusty winds and frequent lightning. Sunday through Thursday: Conditions across the local waters will remain quiet through Monday with northeast or east flow generally no more than 10 knots. However, this will change as we get into the middle of the week and a cold front pushes through from the north. This will result in a strong surge of northeast flow beginning Wednesday and continuing through Thursday. There will be increasing probabilities of gusts into the 25-30 knot range with seas building upwards of 6 ft as well. Small Craft Advisories will likely be needed for some, if not all, of the local waters including Charleston Harbor. Also of note, rounds of thunderstorms will be possible at times ahead of an along the front which could bring the potential for strong wind gusts and frequent lightning. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$