textproduct: Charleston

WHAT HAS CHANGED

The Aviation section was updated for the 22/12z TAFs.

KEY MESSAGES

- 1) Dry conditions and below normal temperatures will continue into early next week.

- 2) Strong northeast flow this weekend and into early next week will result in several coastal hazards including tidal flooding, rip currents, high surf, and beach erosion.

DISCUSSION

KEY MESSAGE 1: Dry conditions and below normal temperatures will continue into early next week.

Through Daybreak: Strong radiational cooling is in progress early this morning. The boundary layer has fully decoupled and the airmass remains very dry beneath clear skies. Thermal falls will remain steady through daybreak. Temperatures were lowered significantly from the 22/01z NBM with many locations already near or below its forecasted low temperatures as of 22/05z. The NBM warm bias is typically significant in strong radiational cooling regimes and this morning is no different. Temperatures are generally running about 2-5 degrees colder than 24 hours ago. Expect most areas inland to drop into the lower 40s (some upper 30s) with mid 40s prevalent across the coastal corridor and mid-upper 50s at the beaches.

Today and Tonight: The surface pattern across the Southeast U.S. will remain unchanged through tonight with strong high pressure remaining in control. Another day of full insolation is expected with low-level thickness schemes supportive of highs in the mid-upper 70s, consistent with the various deterministic and statistical guidance. There are signals that a weak sea breeze could develop along the Georgia coast late this afternoon, but no meaningful impacts are expected other than a uptick in surface dewpoints. The boundary layer looks to decouple quickly again after sunset with calm winds prevailing. Some weak recoupling could occur late across the coastal corridor with guidance hinting the pressure gradient could tighten a bit a few hours before daybreak Friday. Temperatures were once again adjusted down quite a bit from the NBM given the expected radiational setup (calm/light winds, clear skies and a dry airmass). Lows will range from the lower-mid 40s inland to the upper 50s/near 60 at the beaches.

Friday through Wednesday: High pressure will strengthen over the Mid- Atlantic States Friday while a coastal trough develops along the Southeast U.S. coast, persisting through the weekend and into early next week. This will cause NE winds to increase, ushering in cooler temperatures, despite dry conditions and abundant sunshine.

High temperatures on Friday will be in the upper 60s to around 70 degrees across our SC counties, and the lower 70s across our GA counties. Temperatures moderate into the lower to middle 70s on Saturday, then rising another 1-2 degrees on Sunday, followed by persisting on Monday. Highs should rise to near normal by the middle of next week. Low temperatures will remain below normal inland, except warmer at/near the beaches.

KEY MESSAGE 2: Strong northeast flow this weekend and into early next week will result in several coastal hazards including tidal flooding, rip currents, high surf, and beach erosion.

High pressure will settle in across New England Friday into Saturday, driving an enhanced pressure gradient along the Southeast coast this weekend and into early next week. This setup will yield strong northeast flow across the area, with the potential for coastal hazards to extend into at least early next week.

Coastal Flooding: Astronomical tides will continue to rise the rest of this week, this weekend, and into next week as we approach the upcoming lunar perigee (10/28) and the next full moon (10/26). In fact, the highest astronomical tides for all of 2026 will come next Tuesday (10/27) and Wednesday (10/28) when Charleston peaks at ~6.9 ft MLLW and Fort Pulaski peaks at 8.9 ft MLLW. We are already seeing the effect of a prolonged period of elevated northeast flow along the coast as current tidal departures are running in the 1.5-2.0 ft range. With another period of strong northeast flow on the way this weekend, these large tidal departures will persist and start to overlap with increasing astronomical tides, providing increased probabilities of seeing a multi-day coastal flooding event for the entire coast. Minor coastal flooding could begin as early as the upcoming late afternoon high tide cycle, and this minor flooding potential will continue through the rest of the week. Over the weekend and into next week, the potential for moderate to even major coastal flooding will increase at Charleston. At Fort Pulaski, minor to moderate coastal flooding will be possible during this time period. Of note, the morning high tide cycle will be the dominant high tide of the day.

Coastal Hazards: Strong northeast flow and increased wave action will support an elevated rip current risk over the weekend and into early next week. Also, high surf with breaking wave heights of 5 ft or higher will be possible and High Surf Advisories could be needed. The combination of elevated tides, increased wave action, and persistent gusty northeast winds will almost certainly produce beach erosion, the most significant occurring around the elevated high tides.

Lake Winds: Gusty northeast winds are expected to develop on Lake Moultrie Friday night and continue to early next week. A Lake Wind Advisory could be needed for winds 20 kt or greater and waves 2-3 ft. The combination of steady northeast winds and significant wave action could yield some lakeshore erosion along the southwest side of the lake along with some overwash. This is includes areas from roughly Pinopolis to Blacks Camp near Cross.

AVIATION /09Z THURSDAY THROUGH MONDAY/

22/12z TAFs: KCHS/KJZI/KSAV: VFR through 23/12z.

Extended Aviation Outlook: Gusty northeast winds are expected this weekend.

MARINE

Through Tonight: North to northeast winds will persist into tonight with speeds generally 15 kt or less, highest over the South Carolina and Georgia offshore legs. Seas will average 2-3 ft across the nearshore waters, 3-5 ft over the South Carolina offshore waters and 3-6 ft over the Georgia offshore waters. A Small Craft Advisory remains in effect for the Georgia offshore waters through tonight.

Friday through Monday: High pressure will strengthen over the Mid-Atlantic States Friday while a coastal trough develops along the Southeast U.S. coast, persisting through the weekend. The interaction between these two features will cause marine conditions to rapidly deteriorate Friday. Winds and seas will substantially increase, first necessitating a period of Small Craft Advisories on Friday (including the Charleston Harbor Friday night), and then Gale headlines for all of our Atlantic waters by late Friday night, lasting through the weekend. Strong gales are possible during this time period, especially for the 20-60 nm waters. There will be steep, short period wind-driven waves as well. Winds and seas start to trend lower on Monday, but there we may need to maintain marine headlines through Tuesday.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...Small Craft Advisory until 6 AM EDT Tuesday for AMZ384.