Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
152 FXUS62 KCHS 240103 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 803 PM EST Sun Nov 23 2025 .SYNOPSIS... High pressure will prevail early this week, before a cold front impacts the area mid week. High pressure and dry weather is expected to return for Thanksgiving through late week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Tonight: Aloft, a weak trough currently across the Southeast United States will shift east across the nearby Atlantic, allowing modest mid-lvl ridging during the overnight period. At the sfc, high pressure will continue to expand across the region behind a front, which will continue to shift south across Southeast Georgia with time and past the Altamaha River by late evening. The main issue for the overnight period will continue to focus on fog potential. Latest guidance indicates low condensation pressure deficits and weak/modest low-lvl wind fields across a majority of the local area overnight while sfc winds remain light/calm under mostly clear skies. Lowest condensation pressure deficits and weakest low-lvl flow are most prevalent across Southeast Georgia, where the bulk of model guidance favors areas to potentially widespread fog developing after midnight. Some fog could become dense late, particularly across coastal Southeast Georgia and inland for locations along/south of I-16. Here, light northeast flow off the Atlantic should advect higher dewpts (low-mid 60s) across land while sfc temps dip into the mid-upper 40s inland to low-mid 50s near the coast. Based on the anticipated environment and persistent trend in model solutions, fog coverage has been increase across all areas tonight, with the mention of dense fog across portions of Southeast Georgia for a 2-4 hours late night. A Special Weather Statement or Dense Fog Advisory could eventually be required for much of the local area tonight. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Mid level ridging will pass across the Southeast on Monday, before transitioning offshore Tuesday in advance of the next trough. At the surface, the center of high pressure initially over the mid-Atlantic states will gradually shift off the coast. Most areas will stay dry, although a few showers are possible on Tuesday. Temperatures will lean on the warmer side of normal, especially on Tuesday when some areas in southeast Georgia possibly reach the low 80s. A large mid level trough will move into the eastern CONUS on Wednesday, helping to drive a cold front to the region. The forecast area will be in the warm sector much of the day, allowing highs to once again peak well above seasonal norms in the upper 70s to around 80. The main question will be the precip coverage. Most guidance would hint at a diminishing precip trend as the front progresses into the area. Ensemble means, and even the 75th percentile, are less than a couple tenths of an inch of rainfall. The front should pass offshore Wednesday evening, bringing an end to any rainfall. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Dry and noticeably cooler weather is expected for the entire period as high pressure builds into the area. Could see low temperatures fall to around freezing or below over the far interior both Thursday and Friday nights, but as a reminder, the local frost/freeze program has ended due to the widespread freeze earlier in the month. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... VFR conditions are expected at CHS/JZI/SAV terminals through ~06Z Monday. Latest guidance indicates a higher potential for fog developing at the terminals during the second half of the night. For CHS/JZI, have introduced prevailing MVFR vsbys between 06Z-1430Z Sunday with TEMPO groups of 1/2SM FG between 09-13Z Sunday. VFR conditions should then return by 15Z Monday then persist through 00Z Tuesday. For SAV, fog potential appears higher, so have introduced prevailing IFR vsbys between 06Z-08Z and 13-1430Z Sunday with a prevailing group of 1/2SM FG vsby between 08Z-13Z. There is some possibility of vsbys being reduced even more during this timeframe late tonight. VFR conditions should then return by 15Z Monday, then persist through 00Z Tuesday. Extended Aviation Outlook: Prevailing VFR. && .MARINE... Through Tonight: No marine concerns through tonight. High pressure will continue to expand into the area. Northeast winds will average less than 15 knots with seas 1-2 feet. Monday through Friday: High pressure initially over the mid- Atlantic states will shift offshore towards the middle of the week. This will allow northeast winds to eventually turn more southerly. Speeds should average 15 knots or less with seas no higher than 2-4 feet. A cold front will approach from the west on Wednesday, crossing the waters Wednesday night. Winds will increase as a result, bringing some potential for a Small Craft Advisory, primarily over the outer Georgia waters, but it seems marginal at this point. High pressure will build in for late week. Pressure gradient remains fairly tight, so winds will remain elevated Thursday into Friday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...