FXUS62 KCHS 251740 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 1240 PM EST Wed Feb 25 2026
.WHAT HAS CHANGED...
The Aviation Section has been updated for the 18Z TAF issuance. Precipitation amounts of risen slightly for Key Message 1, with a second Key Message introduced for the Lake Wind Advisory for Lake Moultrie. The Marine Discussion has been updated to reflect the ongoing and expanded Small Craft Advisories into Thursday.
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.KEY MESSAGES...
- 1) A passing front will result in widespread rainfall from late Thursday lingering into early Saturday.
- 2) Strong winds and rough waves on Lake Moultrie will create
hazardous conditions for small craft on Thursday.
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.DISCUSSION...
KEY MESSAGE 1: A passing front will result in widespread rainfall from late Thursday lingering into Saturday.
A slow moving and broad upper level trough will begin to slide over the southeast region overnight into Thursday morning, with a cold front similarly slowly moving south into TN/NC. As weak shortwaves work their way around the base of the trough, a surface low pressure looks to form along the front, and will lead to increasing chances for light rain and/or drizzle throughout the day on Thursday. Initially, most of this activity will be confined to areas west of the I-95 corridor on during the morning hours, with chances for rain expanding to include the rest of the forecast area later in the afternoon and overnight into Friday as the surface front/low sag southwards.
Majority of the rainfall is expected on Friday ahead of and along the main shortwave, with precipitable water values climbing into the 1-1.25" range. Models have come in a touch wetter, with storm total rainfall now looking to be in the 1-1.5" range. Guidance continues to indicate that flooding doens't look to be a threat, with the high res models that go out far enough showing showers/thunderstorms remain progressive with quick upper level flow aloft, further made less likely by the ongoing drought conditions. Chances for rain dwindle into Saturday, though confidence remains low as model agreement amongst the various ensembles on the end timing of the rain is low.
KEY MESSAGE 2) Strong winds and rough waves on Lake Moultrie will create hazardous conditions for small craft on Thursday.
Ahead of an approaching cold front, the surface pressure gradient will increase markedly overnight, resulting in breezy winds developing into Thursday morning. In addition, under a strengthening low-level jet, 50 knot winds in the 850hPa layer will mix down throughout the morning hours, with the combination creating southwest winds 15 to 20 knots with gusts up to 25 knots. This will lead to hazardous conditions on Lake Moultrie.
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.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
18Z TAFs: VFR conditions will prevail. As noted previously, expect breezy southwesterly winds to continue this afternoon as cloud cover gradually builds in from the west. While gusts may wane a bit throughout the overnight period, should see a resurgence occur near daybreak Thursday. Will then see gusts between 20-25 kt persist for the reminder of the period.
Extended Aviation Outlook: Flight restrictions will be likely late Thursday night into Friday as a front dives across the region. Occasional flight restrictions could persist into Saturday, though conditions should largely be trending toward VFR.
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.MARINE...
Ahead of an approaching cold front, the strong surface pressure gradient will continue the breezy winds over the waters from South Santee to Edisto this afternoon. In addition, as the pressure gradient increases this afternoon into the evening hours, breezy winds expand to include all of our waters, including the Charleston Harbor. Have therefore expanded the Small Craft Advisory given the expected widespread 25+ knots across the waters, with 6 foot seas expected to remain 20+nm out. Guidance does indicate that there is a ~40% probability for seeing Gale strength winds starting near daybreak and ending in the afternoon, which is noted in the HRRR and RAP, but looks to remain confined to a narrow corridor roughly 20nm out to see in the waters from South Santee to Edisto, but that is a trend worth monitoring.
In addition to the breezy winds, will likely see some light showers Thursday morning, with additional and higher chances for showers and thunderstorms returning Thursday afternoon and into the evening hours and continuing through most of Friday. The cold front is then anticipated to shift offshore by Friday night with high pressure returning during the weekend, keeping conditions below Small Craft Advisory levels into early next week.
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...Lake Wind Advisory from 6 AM to 5 PM EST Thursday for SCZ045. MARINE...Small Craft Advisory from 6 AM to 5 PM EST Thursday for AMZ330.
Small Craft Advisory until 7 PM EST Thursday for AMZ350. Small Craft Advisory until 7 PM EST Thursday for AMZ352. Small Craft Advisory from 7 PM this evening to 4 PM EST Thursday for AMZ354. Small Craft Advisory from 7 PM this evening to 7 PM EST Thursday for AMZ374.
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APT/SST