FXUS62 KCHS 090035 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 735 PM EST Thu Jan 8 2026
.SYNOPSIS...
High pressure will extend across the region through Saturday. A cold front will push offshore Sunday morning followed by another area of high pressure. Yet another cold front could impact the Southeast States by the middle of next week.
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.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Tonight: Aloft, the axis of a ridge will remain near the Southeast Coast well in advance of a trough traversing the Central United States. At the sfc, a weak stationary front near the South Carolina/Georgia state line is anticipated to make northward progress across the local area this evening, helping set up prime conditions for fog formation under a southwest flow advecting warm and moist air to the region overnight. Much like the previous night, the bulk of guidance indicates visibility reductions starting mid to late evening, with favorable condensation pressure deficits, a light/calm sfc wind and a weak 1000mb geostrophic wind (5-10 kt) setting the stage for another round of dense fog as temps cool to around sfc dewpts in the mid 50s, especially during the second half of the night once cirrus clouds thin and/or depart to the east.
The latest 12Z HREF indicates areas of dense fog (60-80 percent probabilities of 1/4 mile or less visibility) across Southeast Georgia and Southeast South Carolina after midnight, and is also suggestive (as with other guidance) that sea fog drifts onshore early-mid evening within an onshore wind, mainly where ongoing dense marine fog remains close to beaches from Edisto Island, SC and south near coastal locations in Southeast Georgia. Additionally, local soundings indicate similar profiles to the previous night, with a large inversion in place, low-lvl moisture trapped below it and weaker low-lvl winds supportive of another round of low stratus, some of which potentially builds down to the sfc given the weak front in the vicinity. Given the setup and anticipated conditions, a Special Weather Statement and/or Dense Fog Advisory will likely be needed for all areas as trends unfold overnight.
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.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Friday and Saturday: A warm airmass will remain in place through Saturday with the region with holding along the southern periphery of high pressure as it shifts offshore of the Mid-Atlatic states. Another round of fog appears likely Friday night with low condensation pressure deficits and high low-level moisture levels progged. Some of the fog could be dense, possibly reaching Dense Fog Advisory criteria. Dry conditions will mostly prevail as ridging aloft builds and shift east of the region ahead of storm system organizing over the Southern Rockies and the Desert Southwest. A few marine-based showers could brush parts of the coast, mainly from Tybee Island north, as the return flow veers more southerly as a weak coastal trough lifts north Friday morning. Significant rainfall is unlikely and looks to mainly concentrate Friday night into Saturday coincident with a strengthening low-level jet ahead of an approaching cold front. Highs look to warm into the upper 70s/lower 80s both afternoons (except cooler at the beaches) and overnight lows will range from the upper 50s/near 60, except a few mid 50s possible in the Francis Marion National Forest. Record highs could be challenged each day with lows Friday night challenging the record high minimums. See the climate section below for specific records.
Saturday Night and Sunday: A cold front will push offshore early Sunday morning as a powerful shortwave pivots across the Great Lakes region. A band of rain associated with the front will likely be in a weakening phase as the corridor of strongest forcing with the Great Lakes shortwave with the right entrance region of the 165 kt polar jet pass by well to the north. How quickly the frontal band weakens is still a bit uncertain with areas across far interior Southeast Georgia the most likely to see measurable rainfall. Pops will range 30-60% for now, highest in the Allendale-Reidsville corridor, but further refinements in both the QPF and pops are likely. Lows will range from the lower 50s well inland to the upper 50s at the coast. The record high minimums could again be challenged, especially at KCHS. Highs behind the front Sunday will range from the lower 60s well inland to the mid 60s east of I-95. See the climate section below for specific records.
Modest cold air advection could push winds to near Lake Wind Advisory levels on Lake Moultrie Sunday afternoon.
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.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Modest cold air advection could push winds to near Lake Wind Advisory levels on Lake Moultrie Sunday night. Otherwise, temperatures will return to more seasonable levels next week as a modified Canadian airmass prevails across the Southeast States. A could front could bring an increased risk for light rainfall by mid- week.
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.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR conditions should prevail at CHS/JZI terminals early evening, before MVFR vsbys arrive in the 02-03Z Friday timeframe. TEMPO IFR conditions are in place at SAV between 00-02Z due to low cigs and are expected to prevail thereafter during the night. Conditions are expected to deteriorate at all terminals during the night, likely going IFR or lower by 06Z at CHS/JZI terminals as well. Fog is likely at all terminals late night, with vsbys around 1/2 mile or less persisting through about 13-14Z Friday. Conditions should improve to MVFR at all terminals late morning Friday, before prevailing VFR conditions arrive by around 15Z Friday.
Extended Aviation Outlook: There is a risk for significant fog impacting all three terminals Friday night into Saturday morning. A band of showers with a cold front may bring reduced vsbys early Sunday morning. Gusty northwest winds are possible Sunday afternoon.
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.MARINE...
Tonight: Local webcams and satellite imagery showed that fog was persisting along the immediate coastline late afternoon, mainly across locations along and south of Charleston, SC into Southeast Georgia, which has already prompted the extension of a Marine Dense Fog Advisory across all local waters while a light onshore wind (5-10 kt) is ongoing, but eventually becomes more southerly overnight (around 5 kt). Conditions could remain improved across the Charleston Harbor for the next couple hours, but a weak front will lift northward this evening, likely placing dense fog conditions across the harbor and northern portion of nearshore waters along Charleston County overnight. Given warm/moist air advecting across local waters and sea fog already in place along with with some return of sea fog back north as the night progresses, the Marine Dense Fog Advisory will remain in effect for all local waters through the night and post daybreak Friday morning with visibilities of 1/2 mile or less. Seas will generally remain around 1 ft across most waters overnight.
Friday through Monday: The risk for marine fog could linger over the coastal waters into the day Friday with fog possibly redeveloping Friday night into Saturday as a warm, moist airmass holds across the region. The fog could be dense with vsbys 1 NM or less, so Marine Dense Fog Advisories may be needed. The risk for Small Craft Advisory conditions from both winds and seas will peak Sunday into Sunday night as modest cold air advection occurs behind a cold front.
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.CLIMATE...
Record High Temperatures: January 9: KCHS: 78/2012 KCXM: 76/1974 KSAV: 77/2008
January 10: KCHS: 79/2008 KSAV: 81/1972
Record High Minimum Temperatures: January 9: KCHS: 58/1946
January 10: KCHS: 60/1974 KCXM: 62/1974 KSAV: 63/1937
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...Dense Fog Advisory until 1 PM EST Friday for AMZ330-350-352-
354.
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NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...