Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
507 FXUS62 KCHS 190004 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 704 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 /TONIGHT/... The mid-levels will consist of a shortwave passing to our north this evening and overnight, but zonal flow should prevail overhead through this evening, then transition to WNW flow after midnight. At the surface, a weak coastal should push 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 should be enough breaks to promote efficient radiational cooling, and patchy/areas of fog along the coast, while patchy, light fog is a possibility elsewhere. There is a 30-40% chance along much of the Highway 17 corridor near and south of Charleston for at least patchy dense fog overnight, and a Dense Fog Advisory or Special Weather Statement could eventually be needed, including for locations around the Savannah Metro around 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 /00Z WEDNESDAY THROUGH SUNDAY/... VFR conditions will prevail at CHS/JZI/SAV terminals through 00Z Thursday. However, a weak coastal trough will shift onshore overnight with greater low-lvl moisture content and possibly lead to increasing low clouds and/or fog within a few hours of daybreak Wednesday morning. Guidance suggests the potential for reduced vsbys most likely to occur at SAV, where TEMPO MVFR conditions remain between 10-13Z Wednesday. These conditions could eventually be required at CHS/JZI for the same timeframe, but guidance suggests VFR conditions through the night, and therefore have been left VFR for the next 24-hr period. 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 late week 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...