Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
069 FXUS62 KCHS 182214 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 614 PM EDT Fri Sep 18 2026 .WHAT HAS CHANGED... Key Message 1 and the Aviation section was updated. && .KEY MESSAGES... - 1) Rain chances will then gradually increase this weekend and especially by early next week. && .DISCUSSION... KEY MESSAGE 1: Rain chances will then gradually increase this weekend and especially by early next week. Tonight: Aloft, the forecast area will continue to sit between prominent ridging and an anticyclone to the west and an upper low across the FL peninsula. This will drive northeast flow aloft and also support a similar storm motion. At the surface, a surface trough positioned to the north will be the primary feature of interest. Convection firing over North Carolina should continue to weaken as it pushes should with only remnant shower activity expected as its enters the Lowcountry. Slight chance pops were maintained for parts of the Charleston Tri- County with non-mentionable pops (10% or less) elsewhere across southern South Carolina into Southeast Georgia. Saturday and Sunday: Aloft, a mid-upper lvl low will pass south of the local area, shifting across the Florida Peninsula and to the Northeast Gulf. At the sfc, a weak front will approach from the north this weekend, potentially reaching the local area late Saturday into early Sunday before stalling/dissipating early week. The setup will favor deep moisture transport across the Southeast United States within a southerly flow with PWATs approaching 2.25 inches locally, and likely support unsettled weather conditions in the form of showers/thunderstorms given sufficient forcing and abundant sfc heating (highs in low-mid 90s Saturday, then upper 80s/lower 90s Sunday). Given a moisture rich airmass, rounds of afternoon/evening convection and a front nearby, there could be a low-end threat for locally heavy rainfall and minor flooding issues. However, minimal shear and modest instability will limit the severe weather threat. Monday through mid-week: The previously mentioned mid-upper low feature is anticipated to drift north across the Southeast United States early week, eventually phasing with a longwave trough passing across the Midwest and Northeast United States through mid-week. The passing low along with the arrival of a stronger cold front from the north should lead to a slightly more active weather period in regards to shower and thunderstorm coverage, and could lead to a greater risk for a few strong and/or marginally severe thunderstorms during peak heating hours heading into the middle of the week. Additionally, moisture levels remain high (PWATS 2+ inches), suggesting at least some minor flooding concerns while the front is nearby. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... 19/00z TAFs: KCHS/KJZI/KSAV: VFR through 20/00z. A few remnant showers from convection dropping south out of North Carolina could approach KCHS and KJZI overnight, but impacts are expected. Extended Aviation Outlook: Shower/thunderstorm chances are expected to increase late weekend and into early next week with the approach of multiple fronts and increasing moisture levels. Periodic flight restrictions are possible. && .MARINE... Tonight: Very quiet conditions will prevail across the local waters. Winds will be strongest this afternoon and through the evening along the land/sea interface with the sea breeze, though winds should peak in the 10-15 knot range. Then overnight, winds will diminish to be 5 knots or less. Seas will average 1-2 ft, except 2-3 ft early for the Georgia offshore leg. Saturday through Wednesday: There are no marine concerns this weekend into early next week as winds/seas are expected to remain well below Small Craft Advisory levels. In general, winds will remain around 10 kt or less with seas in the 2-3 ft range. However, a cold front is anticipated to reach the area by the middle of next week, which should produce an uptick in winds (15-20 kt) and build seas (3-5 ft). Trends will need to be monitored for potential Small Craft Advisory level conditions around mid week. Additionally, shower/thunderstorm coverage is expected to increase next week ahead/along the approaching front. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$