Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
437 FXUS62 KCHS 181747 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1247 PM EST Tue Nov 18 2025 .SYNOPSIS... Dry high pressure is expected to prevail across the area through the week. A cold front is expected to move through this weekend. && .NEAR TERM /THROUGH TONIGHT/... The mid-levels will consist of a shortwave passing to our north this evening and overnight. Though, zonal flow should prevail overhead through this evening, then transition to WNW flow after midnight. At the surface, weak coastal trough axis remains off the coast this afternoon, pushing inland quickly this evening in response to high pressure sliding off the Mid-Atlantic coast. Several hours of weak onshore flow overnight will result in modest moisture pooling along the coast. While some low level clouds likely linger, there will be enough breaks to promote efficient radiational cooling, and patchy to areas of fog are expected along the coast, with patchy, light fog possible elsewhere. There is a 30-40% change along much of the Hwy 70 corridor near and south of Charleston for at least patchy dense fog overnight, and a Dense Fog Advisory may be needed, including for locations around the Savannah Metro, by daybreak Wednesday. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Wednesday: Aloft, a shortwave situated across the Bluegrass state will slowly weaken as it approaches the Mid-Atlantic coastline and a strong upper-lvl ridge will build in locally from from the west. Simultaneously, an associated front will move in tandem with the shortwave, but it is expected to remain north of the region. At the surface, high pressure will be present across the Southeast with deep layer subsidence ushering us into a period of well above normal temps. 850 mb temps reach 1.5 to 2 standard deviations above normal by Wednesday afternoon, bringing highs 10-15 deg above normal, in the upper 70s to lower 80s (away from the beaches, where a sea breeze is likely). Such values would still be several degrees below records, but notably warm for mid November nonetheless. Thursday and Friday: A strong upper-lvl ridge with nearly 590 DM will be present over the Gulf on Thursday and Friday, as a surface low develops across the central CONUS. Expect temperatures to remain well above normal with a rain-free forecast. High temperatures Thursday and Friday will reach near record highs (see Climate section), with low 80s across the SC Lowcountry to the low to mid 80s across SE GA.&& .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... Expect upper-lvl ridging to become suppressed as a progressive shortwave approaches the region on Saturday, and an associated cold front passes through the area on Saturday night. Primary source of uncertainty remains the magnitude of the shortwave to our north. The most likely scenario at this point is that the majority of the forcing associated with the front passes north of the area, but it is enough to keep conditional instability in place locally, and the cold front brings mainly light precip to the area Saturday. The less likely scenario is that the stronger ridging to our south builds northward strong enough to keep the cold frontal passage completely dry. Regardless, QPF is too modest to make much of a dent in the moderate to severe drought that is currently in place across inland portions of the area. Broad high pressure then builds in gradually from the north behind the front Monday, persisting through early next week. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... 18Z TAFs: VFR prevails through this evening, with scattered cloud coverage along the GA and SE SC coast expected to persist with 4kft bases. Then, this evening, a the coastal trough pushes inland quickly as high pressure moves off the coast, allowing for increased LL moisture advection along the coast. There are expected to remain enough breaks in the clouds to allow for efficient radiational cooling, a patch fog is expected to develop mainly along the Hwy 17 corridor near and south of Charleston. As such, have introduced TEMPO MVFR fog within several hours of sunrise Wednesday. Fog will dissipate gradually after sunrise given the lack of gradient. Extended Aviation Forecast: Prevailing VFR. A cold front could bring at least brief flight restrictions Saturday, but the precipitation and wind characteristics of the front remain uncertain. && .MARINE... Benign marine conditions persist through the end of the workweek with mainly light winds and 1-2 ft seas. With warm conditions over land, a sea breeze is likely each afternoon through Friday, bringing locally gusty winds near the coast each afternoon. A cold front could impact the area Saturday, but significant uncertainty remains with respect to the strength of the front and the wind and precip characteristics associated with it. Stay tuned to subsequent forecasts as the potential for hazardous marine conditions Saturday into Sunday will be refined in the coming days. && .CLIMATE... Record High Temperatures: November 19: KCHS: 83/1942 KCXM: 82/1958 KSAV: 85/1942 November 20: KCHS: 82/1942 KCXM: 78/1900 KSAV: 83/1942 November 21: KCHS: 83/1973 KCXM: 80/1942 KSAV: 82/2011 November 22: KCHS: 83/1942 KCXM: 79/1997 KSAV: 82/1997 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...