FXUS62 KCHS 040600 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 200 AM EDT Thu Sep 4 2025
.SYNOPSIS...
High pressure will extend across the area through late week. A cold front will move through from the northwest late Sunday, stalling just offshore through the middle of next week.
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.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, a large trough will pivot across the Great Lakes region, placing a west-southwest flow across the Southeast United States. At the sfc, high pressure will prevail across the region, although will show signs of nudging offshore along the Mid-Atlantic and Southeast Coast as weak h5 shortwave energy ripples across the region during the day. The atmosphere is quite dry locally as evidenced by latest water vapor imagery and soundings across the area. Other than a few clouds associated with mid-lvl vort energy, conditions will remain precip-free throughout the day. Temps will become noticeably warmer under ample sunshine when compared to the previous day, likely due to sfc winds turning more east-southeast as high pressure nudges closer to the Mid-Atlantic Coast. Although a sea breeze circulation will keep high temps a bit cooler along the beaches (mid 80s), 1000-850 mb thickness values support highs in the low-mid 90s away from the coast, warmest across Southeast Georgia.
Tonight: Aloft, the mid-lvl trough tracks toward the Northeast, losing some amplitude, but continuing to place the local area along its base. At the sfc, high pressure will prevail through the night, leading to another quiet/dry period. Winds are expected to decouple early under clear skies, becoming light/calm away from the beaches for a majority of the night. Overnight lows should generally range in the mid-upper 60s inland to low-mid 70s near the coast.
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.SHORT TERM /FRIDAY THROUGH SUNDAY/...
High pressure will gradually lose its influence over the local area Friday and Saturday as it weakens and retreats northeast. An increasing southerly flow will result in warming temperatures with highs back in the low to mid 90s away from the coast. No appreciable forcing will exist Friday and Saturday, precluding rain chances.
An upper shortwave will move in on Sunday and a weak cold front will sag into the area from the northwest in the afternoon. Scattered showers and thunderstorms are possible, mainly in the afternoon.
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.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Cool, dry high pressure will build in from the north next week as the front remains stalled just off the coast. A weak coastal trough is expected to develop early next week, maintaining some rain chances across coastal areas. Temps will be noticeably cooler.
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.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 06Z Friday.
Extended Aviation Forecast: VFR conditions will prevail through at least Friday. There is a low chance for some morning fog and stratus Saturday morning, mostly inland. The next chance of showers and thunderstorms will come Sunday afternoon. Ceiling restrictions possible Sunday night and Monday as a front sags into the area.
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.MARINE...
Today and Tonight: High pressure will dominate the pattern with a weak pressure placed across local waters throughout the day and night. East winds in the 5-10 kt range will be common today, although an uptick in the 10-15 kt is possible along the land/ocean interface where a sea breeze circulation develops, then shifts inland this afternoon. Overnight, winds continue to veer out of the south/southeast as high pressure nudges more offshore, although wind speeds will likely remain at or below 10 kt through the night. Seas will generally range between 2-4 ft today (largest across outer Georgia waters), but will subside to 1-3 ft tonight.
Quite marine conditions expected Friday through Sunday. A tightening NE gradient will develop Sunday night as high pressure strengthens from the north and a front remains stalled just offshore. We'll likely need Small Craft Advisories for most if not all marine zones for the brunt of next week.
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.TIDES/COASTAL FLOODING...
Astronomical tide levels will continue to increase today through the weekend, getting as high as 6.4 ft MLLW by the Sunday evening high tide cycle. Winds will become less favorable for large tidal departures during this time period, but observed peak tides could still top out around 7 ft MLLW at Charleston each evening, starting with the high tide cycle this evening.
Astronomical tide levels will remain high from late in the weekend into early next week thanks to the upcoming full moon (9/7) and perigee (9/10). Winds are expected to become more favorable for increased tidal departures early next week, which will produce an increasing probability of at least minor coastal flooding.
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...None.
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NEAR TERM...DPB SHORT TERM...JRL LONG TERM...JRL AVIATION...DPB/JRL MARINE...DPB/JRL