FXUS62 KCHS 101139 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 639 AM EST Wed Dec 10 2025
.SYNOPSIS...
A cold front will move through this evening and push offshore Thursday morning with another cold front possibly moving through late Sunday. Cold high pressure will then build in.
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.NEAR TERM /THROUGH TONIGHT/...
Quick update to issue a Freezing Fog Advisory. Law enforcement reported icy bridges around the Charleston metro area with multiple accidents. The advisory goes through 9am when temperatures will warm above freezing and any lingering fog should dissipate.
Today: Aloft, zonal flow will prevail across the region ahead of a vigorous trough diving across the Upper Midwest and into the TN/OH Valley. At the surface, high pressure will start the day across the region before getting suppressed to the south as a cold front draws closer from the northwest. The forecast remains dry with plenty of dry air across the region. Southwest flow ahead of the front will yield a much warmer day than the last several, with highs getting up into the upper 50s and low 60s. The warmer temperatures will produce better mixing an breezy southwest flow at times in the afternoon. Frequent gusts into the 15-20 mph range are expected, which could start to tick upward closer to sunset as the better low-level wind field starts to press in from the west.
Tonight: The cold front will pass through after midnight and the best low-level wind field will come through just ahead of the front during the evening hours. The breeziest conditions are expected to stretch across the period beginning around 8-9 pm through about 1-2 am. During this time, frequent gusts of 15-20 mph are expected everywhere, with 20-25 mph along the coastal corridor. With winds remaining elevated through the night, the increased mixing will prevent temperatures from getting too cold. Still, mid to upper 30s are advertised inland which will range to the low 40s along the coast.
Lake Winds: Southwest winds across Lake Moultrie will gradually turn more westerly and strengthen this evening and through the early morning hours on Thursday. Frequent gusts into the 25-30 knot range are expected, and a Lake Wind Advisory is in effect.
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.SHORT TERM /THURSDAY THROUGH SATURDAY/...
Dry high pressure will prevail through the period. There will be a steady warming trend as the high shifts offshore and a warm advection regime sets up. Highs in the low to mid 50s Thursday will rise to mid/upper 60s by Saturday.
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.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
A strong cold front will move through Sunday evening, followed by a brief cooldown, then gradual warming. We could see a few hours of Cold Weather Advisory wind chill (~20F) over the northern counties Monday morning.
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.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
The 12z TAF period begins with patchy dense fog around the area and periodically impacting the terminals. Most of the fog is around KCHS and KJZI, and especially KCHS. The fog at KCHS has been dense at times and this could continue through about 14z. KJZI has so far evaded the fog, but it could still roll through there as well through about 14z. Once any lingering fog dissipates by mid morning, VFR conditions are expected through the rest of the period. The main issue will be winds. Southwest winds will become breezy this afternoon with gusts into the 15-20 knot range. The strongest period of winds will come along and with a cold front this evening and into the early morning hours. Gusts into the 20-25 knot range will be possible during this time as winds turn more westerly and eventually northwesterly.
Extended Aviation Outlook: VFR.
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.MARINE...
Today through tonight: Conditions across the local waters will start off pretty quiet this morning before steadily ramping up through the rest of the day as a cold front approaches from the northwest. By sunset, we expect to see a solid 15-20 knots across all waters with gusts starting to reach up to 25 knots in the Charleston County waters. The strongest winds are then expected from the evening through the early morning hours when wind speeds are expected to increase into the 20-25 knot range with frequent gusts up to around 30 knots. There will even be a window of time from the late evening into the early morning hours where wind gusts around gale force will be possible in the Charleston County waters and the outer GA waters. We will maintain the Small Craft Advisory for now, but it isn't entirely out of the question that a marginal Gale Warning could be needed with future forecast updates. Also, we have expanded the Small Craft Advisory to include Charleston Harbor for the evening and early morning hours. Seas will ramp up with the increasing winds, becoming 3-5 feet by early evening and then peaking in the early morning hours as 6 ft seas get into the SC nearshore waters and up to 7 feet in the outer GA waters. Winds and seas will both start to diminish a bit as sunrise Thursday approaches, but will overall conditions will continue to support the ongoing Small Craft Advisories.
6 ft seas will continue over the offshore GA waters through Thursday morning which necessitates a continuation of the Small Craft Advisory.
Solid Small Craft Advisory conditions anticipated Sunday night through Monday for most if not all waters after a cold front sweeps through.
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...Lake Wind Advisory from 6 PM this evening to 5 AM EST Thursday
for SCZ045. Freezing Fog Advisory until 9 AM EST this morning for SCZ050- 052.
MARINE...Small Craft Advisory from 6 PM this evening to 5 AM EST
Thursday for AMZ330-354. Small Craft Advisory from 3 PM this afternoon to 7 AM EST Thursday for AMZ350-352. Small Craft Advisory from 3 PM this afternoon to noon EST Thursday for AMZ374.
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NEAR TERM...BSH SHORT TERM...JRL LONG TERM...JRL AVIATION...BSH/JRL MARINE...BSH/JRL