FXUS62 KCHS 161728 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 128 PM EDT Tue Sep 16 2025
.SYNOPSIS...
High pressure will extend across the region. Low pressure will meander near the North Carolina Outer Banks through the middle of the week. A cold front could approach from the north early in the weekend.
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.NEAR TERM /THROUGH TONIGHT/...
The 500 mb level will consist of a roughly 580 dam Low hovering over the eastern Mid-Atlantic States. At the surface, Low pressure will shift from the Outer Banks of NC this evening into the eastern Mid-Atlantic region overnight. Meanwhile, High pressure prevail across our region. The High will bring our area dry conditions with some high cirrus clouds. There should be a decent amount of radiational cooling, especially with very light to calm winds inland. Lows will range from the upper 50s far inland to the mid/upper 60s at/near the beaches.
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.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Aloft, low pressure centered across the Mid-Atlantic States on Wednesday will slowly weaken and become an open wave of weak troughing extending north/south along the eastern periphery of the Appalachians into late week with some subtle hints of weak ridging occurring by the weekend. At the sfc, weak high pressure will remain the primary weather feature across the local area, resulting in dry weather conditions through Friday, although there remains a low possibility of an isolated shower on Thursday given h5 shortwave energy exiting off the Carolina Coast. The more noticeable change to the weather will be attributed to warming temps, as 1000-850 mb thicknesses increase each day while the center of the mid-upper lvl trough shifts north/weakens and becomes replaced with subtle ridging. In general, high temps should range between the mid-upper 80s across Southeast South Carolina to around 90 away from the coast across Southeast Georgia on Wednesday, followed by upper 80 to lower 90 high temps away from the beaches Thursday and Friday. Low temps will remain slightly more mild than previous days, generally in the mid-upper 60s inland to lower 70s near the coast each night.
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.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Aloft, weak mid-lvl ridging will gradually give way to an incoming trough early next week. At the sfc, high pressure will wedge southward across the Mid-Atlantic into the Southeast States, likely resulting in noticeably cooler conditions by late weekend within a northeasterly sfc flow. Lower-end rain chances remain in the latest forecast on Sunday and Monday (20-40%), with the bulk of activity anticipated closer to the coast where moisture convergence is higher as troughing occurs across the nearby Atlantic and the northeasterly wind drives activity onshore. In general, high temps should peak in the low-mid 80s near the coast to upper 80s/lower 90s well inland Saturday, then generally low-mid 80s (warmest across inland Southeast Georgia) Sunday and Monday. Overnight lows remain in the mid-upper 60s inland to lower 70s near the coast.
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.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
18Z TAFs: VFR.
Extended Aviation Forecast: VFR conditions are expected at CHS/JZI/SAV terminals through Saturday. Gusty northeasterly winds (15-20 kt) are possible with a wedge of high pressure Saturday and Sunday. Brief flight restrictions are also possible with showers on Sunday.
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.MARINE...
Tonight: Low pressure will shift from the Outer Banks of NC into the Mid-Atlantic region. Meanwhile, High pressure prevail across our region. This will lead to tranquil conditions across our coastal waters. Sustained winds should remain 10 kt or less, while seas will be 2-3 ft within 20 nm and 3-4 ft for the GA waters beyond 20 nm.
Wednesday through Sunday: Weak high pressure will prevail across local waters through Friday, resulting in no marine concerns during the second half of the week. In general, southerly winds will be no higher than 10-15 kt with seas ranging between 1-3 ft, largest across outer Georgia waters. High pressure will begin to wedge south across the region over the weekend, placing a stronger pressure gradient across local waters between a wedge front to the north and troughing east of Florida. Conditions could support Small Craft Advisories across a portion of local waters later Saturday through Sunday, with northeasterly winds gusting up to 20-25 kt and seas building up to 5-7 ft.
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.EQUIPMENT...
The KCLX radar will be down for maintenance from September 16-18th for component upgrades. Users are encouraged to use adjacent WSR-88D radar sites. These radars include:
KCAE: Columbia, SC KLTX: Wilmington, NC KJAX: Jacksonville, FL KVAX: Moody Air Force Base, GA KJGX: Robbins Air Force Base, GA:
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...None.
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NEAR TERM... SHORT TERM...DPB LONG TERM...DPB AVIATION...DPB MARINE...DPB