FXUS62 KCHS 240624 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 124 AM EST Tue Feb 24 2026
.WHAT HAS CHANGED...
Minor adjustments made to Key Message 1 for cold weather prior to daybreak. Minor adjustments made to Key Message 2 for rainfall chances Thursday and Friday. The Aviation Section has been updated for the 06Z TAF issuance. The Marine Section has been updated for extending Small Craft Advisories tonight and hazardous conditions mid to late week.
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.KEY MESSAGES...
- 1) Cold weather with sub-freezing temperatures early this
morning.
- 2) A passing front will result in widespread rainfall from
late Thursday into Friday.
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.DISCUSSION...
KEY MESSAGE 1: Cold weather with sub-freezing temperatures early this morning.
Modified arctic high pressure centered near the lower Mississippi River Valley will continue to shift south to the north-central Gulf Coast prior to daybreak, placing a somewhat enhanced pressure gradient across Southeast South Carolina and Southeast Georgia through much of the night. The setup will keep some degree of wind in place for the next 2-4 hours, although there remains some indication that the gradient will relax just enough for the boundary layer to partially decouple near daybreak. The anticipated trend in sfc winds under clear skies supports temps dipping into the mid- upper 20s inland (lower 30s for coastal areas) near daybreak. As winds weaken with the approach of coldest temps, wind chills are expected to bottom out in the 20-25 degree range, lowest inland. A few spots still have the potential of dipping into the upper teens well inland, but the duration/coverage of the event is rather brief/small. Have opted for no Cold Weather Advisory given the expected scenario late/around daybreak.
KEY MESSAGE 2: A passing front will result in widespread rainfall from late Thursday into Friday.
Aloft, expect broad mid-lvl troughing to develop across the mid- South on Thursday, and then track towards the Eastern Seaboard overnight into Friday. At the surface, a surface low will track northeastward across the mid-South on Thursday with an associated cold front. Expect moisture lvls to return to the region on Thursday ahead of the approaching front. It's fairly high model agreement that scattered showers should develop in the far inland counties on Thursday morning and remain in that general area through the evening, before overspreading into the rest of the region on Thursday night into Friday morning. There remains a bit of uncertainty of how quickly the rainfall should clear off the coastline as this timeframe ranges from Friday night into Saturday morning. Some instability could be present ahead of the front on Friday, therefore the mention of thunderstorms has been noted in the forecast. It's still too early in the forecast to discuss rainfall amounts, however flooding rains does not seem to jump out at the moment (esp. with the ongoing drought). High temperatures will be a few degrees above normal throughout this period.
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.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 06Z Wednesday.
Extended Aviation Outlook: VFR conditions likely to persist through at least Thursday. A front should bring flight restrictions late Thursday night into Friday. Occasional flight restrictions could persist into Saturday.
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.MARINE...
Prior to Daybreak: High pressure spreading across the Deep South will continue to hold an enhanced pressure gradient across local waters early this morning, and support northwest winds gusting to around 25 kt for much of the night. Small Craft Advisories continue across nearshore waters through 5 AM and across offshore Georgia waters through 7 AM. Seas will subside through daybreak, generally ranging between 2-4 ft nearshore by daybreak.
Today and Tonight: High pressure centered west of the region will continue to shift south across the Gulf, then gradually slide east across the Atlantic this afternoon into tonight, favoring winds and seas that remain below Small Craft Advisory levels across all local waters. There are some hints of the pressure gradient intensifying late night as troughing passes to the north, which could support southwest winds gusting up to 20-25 kt within a few hours of daybreak while seas build up to 3-5 ft. Small Craft Advisories could eventually be needed across a portion of local waters heading into daybreak Wednesday.
Wednesday: Southwesterly winds will likely approach Small Craft Advisory lvls across the South Carolina nearshore waters and the offshore Georgia waters on Wednesday in response to a re-tightening of the pressure gradient. Also, with some south-southwesterly swell building into the waters, there is a possibility of some 6 footers reaching into the nearshore Charleston waters and offshore Georgia waters on Wednesday as well.
Thursday and Friday: An approaching cold front from the west on Thursday will yield elevated winds and seas across most of the local waters and conditions will likely warrant the need for Small Craft Advisories on Thursday into Friday. South-southwesterly swell should build into the local waters again on Thursday morn. and seas will range from 4 to 6 ft through early Friday morning. Expect the front shifts offshore by Friday night and marine conditions subside.
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.CLIMATE...
Record Low Temperatures:
February 24: KSAV: 25/1989
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...Small Craft Advisory until 5 AM EST early this morning for
AMZ350-352-354. Small Craft Advisory until 7 AM EST this morning for AMZ374.
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Dennis/DPB