FXUS62 KCHS 100555 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 1255 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/...
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 /06Z WEDNESDAY THROUGH SUNDAY/...
As the 06z TAF period begins the forecast looks to be a bit tricky through the next 6-8 hours. Observations across the area show there is some patchy fog developing and satellite imagery shows a slowly expanding area of stratus down around KSAV. The main forecast challenge concerns what happens with this area of stratus and whether or not it will expand over the next few hours. Model guidance suggests that this will happen and given there is still plenty of low-level moisture and very light surface winds, it seems plausible. Therefore, we have initiated KSAV with MVFR ceilings and don't return conditions to VFR until 09z. At KCHS and KJZI, shallow ground fog is already ongoing and we have introduced a TEMPO group to account for MVFR ceilings roughly from 08-09z through 11-12z.
For the rest of the period, VFR conditions will prevail and the main forecast challenge will be winds. Southwest flow will become breezy this afternoon, with gusts as high as 15-20 knots possible. The strongest winds are expected this evening through the early morning hours as a cold front passes. Winds will turn more westerly with time and gusts up to around 25 knots will be possible.
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.
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