FXUS62 KCHS 170640 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 240 AM EDT Tue Mar 17 2026
.WHAT HAS CHANGED...
The Marine section has been updated and the Aviation section has been updated for the 06z TAF issuance.
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.KEY MESSAGES...
- 1) Frost/freeze is possible this morning through Wednesday
night.
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.DISCUSSION...
KEY MESSAGE 1: Frost/freeze is possible this morning through Wednesday night.
Cold high pressure continues to spread into the area early this morning following the evening cold frontal passage. We still seem to be on track for a light freeze across far interior SC/GA close to daybreak this morning. A Freeze Warning continues until 10 am.
A more widespread freeze is anticipated tonight as the cold air advection regime transitions to a radiational cooling setup with mostly clear skies and diminishing winds. Some mid-20s lows are possible in rural areas across inland GA/SC. We felt confident enough to go with a Freeze Warning for most of the area. At this point we excluded Beaufort, Coastal Jasper, and the coastal zones of GA. Freezing temps could impact far inland portions of some of these zones but coverage did not seem great enough to justify a Freeze Warning. There may be just enough lingering overnight wind across these non-warning areas to preclude the need for a Frost Advisory.
Wednesday night could also feature some frost/freeze issues across the inland half of the area where temps dip to the low/mid 30s and skies remain mostly clear.
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.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
The 06z TAF period begins with VFR conditions at KCHS, KJZI, and KSAV. VFR conditions will prevail and the main forecast issue will be winds. Gusty westerly winds will continue for a few more hours before diminishing a bit. Gusts up to around 20 knots will then pick back up by mid morning as surface heating begins. Winds will remain northwesterly for most of the day, turning a bit more westerly late in the afternoon as gusts decrease closer to sunset.
Extended Aviation Outlook: VFR conditions are expected to prevail.
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.MARINE...
High pressure will continue to build in across the local waters today, though the pressure gradient will gradually weaken and west to northwest flow will steadily diminish. Conditions will steadily improve and we will be able to take down the nearshore Small Craft Advisories by mid morning followed by the outer GA waters by midday. Thereafter, though there could be a few periods of 15-20 knots of flow, overall conditions should remain quiet and below Small Craft Advisory thresholds through the rest of the week and into the start of the weekend.
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.EQUIPMENT...
The KCLX radar is scheduled for radome panel replacement March 17-20, 2026. The radar will be down during this time. Users are encouraged to use data from the following nearby radar sites during the maintenance outage:
KCAE - Columbia, SC KLTX - Wilmington, NC KJAX - Jacksonville, FL KVAX - Moody AFB, GA KJGX - Robbins AFB, GA
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Freeze Warning until 10 AM EDT this morning for GAZ087-088-099-
100-114-115. Freeze Warning from midnight tonight to 10 AM EDT Wednesday for GAZ087-088-099>101-114>116-118-137-138-140.
SC...Freeze Warning until 10 AM EDT this morning for SCZ040-042-043.
Freeze Warning from midnight tonight to 10 AM EDT Wednesday for SCZ040-042>045-047-049-050-052.
MARINE...Small Craft Advisory until 5 AM EDT early this morning for
AMZ330. Small Craft Advisory until 10 AM EDT this morning for AMZ350- 352-354. Small Craft Advisory until noon EDT today for AMZ374.
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BSH/JRL