Charleston Harbor Marine Forecast
| Today...Sw Winds 5 To 10 Kt, Becoming S 10 To 15 Kt With Gusts To 20 Kt This Afternoon. |
| Tonight...Sw Winds 10 To 15 Kt. |
| Fri...Sw Winds 5 To 10 Kt. |
| Fri Night...Sw Winds 5 To 10 Kt. |
| Sat...Sw Winds 5 To 10 Kt. |
| Sat Night...S Winds 10 Kt. |
| Sun...W Winds 10 To 15 Kt. |
| Sun Night...N Winds 10 To 15 Kt, Increasing To 15 To 20 Kt. Waves Building 1 To 2 Ft. |
| Mon...Ne Winds 10 To 15 Kt. |
| Mon Night...Ne Winds 5 To 10 Kt. Unless Otherwise Noted, Waves 1 Foot Or Less. Charleston Harbor Water Temperature 69 Degrees. |
| Area Forecast Discussion National Weather Service Charleston SC 242am EDT Thu Jun 18 2026 .WHAT HAS CHANGED... All sections. .KEY MESSAGES... - 1) Periodic showers and thunderstorms are expected to continue through the weekend. KEY MESSAGE 1: Periodic showers and thunderstorms are expected to continue through the weekend. Today: Fairly quiet weather conditions should continue through the morning as the initial disturbance exits and weak ridging briefly develops aloft. Clear skies combined with strengthening southwesterly flow will yield afternoon temperatures in the low to mid 90s. This should support moderate instability by the afternoon, particularly across southeast Georgia and locations west of the I-95 corridor. Multiple rounds of showers and thunderstorms will likely begin on late Thursday afternoon/evening as anomalously high moisture from the remnant circulation associated with Arthur moves northeastward across central Georgia toward the South Carolina Midlands and Upstate. 00Z.HREF indicates that initial development should be favored across central and southeast Georgia late Thursday afternoon/evening, with showers and thunderstorms spreading towards the South Carolina Lowcountry overnight into Friday morning. Forecast soundings indicate increasing (roughly 30-40 knots) values of deep layer shear this evening into overnight as the remnant circulation passes nearby. Low-level winds could also become locally backed east, or northeast, of the remnant circulation overnight. This would increase low-level shear and briefly enhance the tornado potential, especially across the interior southeast Georgia overnight. However, instability will be the primary limiting factor overnight as SBCAPE values remain well below 1000 J/kg. Nevertheless, the combination of tropical moisture, relatively strong flow, and organized storm motions will support a risk for damaging wind gusts. Also, a brief tornado cannot be ruled out, particularly with isolated storms developing near the remnant circulation. Thus, Storm Prediction Center has highlighted the entire region in a Marginal Risk (Level 1/5) today for severe weather. Localized flooding of poor-drainage and low-lying areas will be also be possible, especially where storms repeatedly track over the same locations. Friday: The remnant circulation should shift away from the region in the morning, and attention will turn towards the cold front settling southward towards the region. Assuming sufficient recovery behind the overnight convection, strong surface heating and surface dewpoints in the low to mid 70s could produce a moderately unstable afternoon environment. Expect showers and thunderstorms to develop along the aforementioned cold front and residual outflow boundaries. The primary hazard will again be damaging wind gusts. The front should slowly pass through the region overnight. Saturday and Sunday: The aforementioned front should slide offshore on Saturday morning as a few showers and thunderstorms linger near the coastline. Thereafter, the typical summertime pattern will dominate the forecast as the daily chances for showers and thunderstorms initiating along the afternoon seabreeze return. However, it's important to note that coverage should be much less than Thursday and Friday. Otherwise, afternoon highs will warm into the upper 80s to low 90s. Marine High pressure will remain off the coast while the remnants of TS Arthur move through the SC Midlands into eastern NC later tonight. A tightening SW gradient will occur over our waters, with the strongest winds after midnight tonight through Friday afternoon. We have Small Craft Advisories for all waters except SC offshore. Marine conditions will subside Saturday with no additional concerns through the weekend. Another front could approach the area on Monday, potentially leading to increasing winds and seas. Rip Currents Increasing swells and gusty winds will lead to a Moderate risk for rip currents at Charleston County beaches Friday. NOAA Charleston SC Office: Watches - Warnings - Advisories GA...None. SC...None. Marine Small Craft Advisory from midnight tonight to 4pm EDT Friday for AMZ340. Small Craft Advisory from 2pm this afternoon to 8pm EDT Friday for AMZ360. Small Craft Advisory from 8pm this evening to 8pm EDT Friday for AMZ362. Small Craft Advisory from 2am to 5pm EDT Friday for AMZ364. Small Craft Advisory from 2am to 8pm EDT Friday for AMZ384. |
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