Charleston Harbor Marine Forecast
| Tonight...Ne Winds 5 Kt Until Early Morning, Becoming Light And Variable. Patchy Fog After Midnight. Areas Of Fog Late. |
| Fri...Nw Winds 5 Kt, Becoming Sw In The Afternoon. Areas Of Fog In The Morning. |
| Fri Night...Sw Winds 5 To 10 Kt. |
| Sat...Sw Winds 10 Kt. |
| Sat Night...W Winds 5 To 10 Kt, Becoming Nw After Midnight. |
| Sun...Ne Winds 10 Kt. |
| Sun Night...Ne Winds 5 To 10 Kt. |
| Mon...Ne Winds 5 To 10 Kt. |
| Mon Night...E Winds 5 To 10 Kt. |
| Tue...Se Winds 5 To 10 Kt. A Slight Chance Of Showers. |
| Tue Night...S Winds 5 To 10 Kt. A Chance Of Showers. Unless Otherwise Noted, Waves 1 Foot Or Less. Charleston Harbor Water Temperature 62 Degrees. |
| Area Forecast Discussion National Weather Service Charleston SC 733pm EST Thu Nov 20 2025 Synopsis Dry high pressure is expected to prevail across the area through the rest of the week. A cold front is expected to sweep across the region Saturday night, followed by more high pressure early next week. Near Term - Until 6am Friday Morning Tonight: A weak front will slowly slip south along the GA/SC coast, then become stationary near the Savannah River this evening, helping set up an environment conducive for fog development overnight. Latest guidance indicates low condensation pressure deficits and weak low-level wind fields across a majority of the local area overnight while surface winds remain light/calm for the bulk of the night. These conditions along with nearshore water temperatures (59- 63 degrees) about a degree cooler than expected dewpoints overnight suggest the potential for areas or even widespread fog to develop across most land zones after midnight (stratus build down and radiational cooling components). Some fog should become dense for a few to several hours later tonight, persisting through daybreak Friday. A Dense Fog Advisory could be required for a large portion of the area overnight and could need to be issued as early as mid- late evening based on trends/observations. Low temperatures will generally range in the mid-upper 50s. Short Term - 6am Friday Morning Through Sunday Short term guidance shows a strong, nearly 590 dm, ridge centered over the Gulf on Friday. NAEFS indicates that Friday, llevel temperatures across portions of the Southeast U.S. will approach 2 units of standardized anomaly. Given the strong ridge over the region, temperatures will remain generally 10 to 12 degrees above normal with no precipitation. High temperatures Friday will reach near record highs (see Climate section), with near 80 across the SC Lowcountry to the low to mid 80s across SE GA. Guidance indicated that the H5 ridge will gradually flatten along the Atlantic coast by late day, resulting in an evening arrival of the cold front. The NBM based forecast is siding with the slower guidance, featuring near record high temperatures and afternoon SCHC PoPs for showers across the extreme inland zones. Temperatures may verify a degree or two warmer than Friday. GFS (Global Forecast System) indicates that H85 temperatures across the region will cool by 3 to 4 degrees in the wake of the cold front Saturday night. Conditions should dry from the top-down, resulting in mostly clear to partly cloudy conditions. Low temperatures Sunday morning are forecast to range in the mid to upper 50s. High temperatures are expected to remain near normals, with near 70 across the SC Lowcountry to the mid 70s across SE GA. Long Term - Sunday Night Through Thursday Early next week, medium range guidance indicates that the H5 ridge axis will ripple across the region on Monday. Conditions will remain dry with moderating temperatures. Through mid-week, the H5 pattern is forecast to feature a 588 DM ridge over the Bahamas as a longwave trough develops over the Great Plains. A large low pressure system over eastern Canada may sweep an elongated front across the region into the mid-week. Tuesday and Wednesday, the forecast will feature above-normal temperatures and SCHC to CHC Probability of Precipitation for showers. Marine Tonight: The primary concern overnight will be the potential development of fog and low clouds across the nearshore waters. A weak front will slowly slip south along the GA/SC coast, expected to become stationary just north of the Savannah River this evening. Areas to patchy fog could develop across the GA nearshore waters this evening, then spread north late tonight. It is possible that a Dense Fog Advisory could be issued tonight. Otherwise, conditions will feature winds around 5 kts with 1-2 ft wave heights. Friday through Sunday: Conditions should remain below Small Craft Advisory Criteria through the period. Broad high pressure should remain across marine zones Friday through much of Saturday, then a weak cold front should sweep across the region late Saturday. Southwest winds ahead of the front are expected to gradually strengthen, reaching 10 to 15 kts on Saturday. Behind the front, winds should veer from northwest Saturday night, then northeast on Sunday between 10 to 15 kts. Seas through the period should favor values between 1 to 2 ft. Climate Record High Temperatures: November 20: KCHS: 82/1942 KCXM: 78/1900 KSAV: 83/1942 November 21: KSAV: 82/2011 November 22: KCHS: 83/1942 KCXM: 79/1997 KSAV: 82/1997 NOAA Charleston SC Office: Watches - Warnings - Advisories GA...None. SC...None. Marine None. |
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