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 310am EDT Fri April 17 2026 .WHAT HAS CHANGED... Increased confidence in record highs being challenged this afternoon, then again Saturday afternoon. Added key message for potential minor coastal flooding along the SC coast this weekend. Rain chances have increased slightly Sunday afternoon, though significant rainfall is still not expected. .KEY MESSAGES... - 1) Record-setting heat possible today and Saturday as dry weather continues. - 2) Minor coastal flooding possible along the South Carolina coast with the evening high tides this weekend. - 3) A cold front will bring low end rain chances Sunday, followed by a brief cooldown early next week. KEY MESSAGE 1: Record-setting heat possible today and Saturday as dry weather continues. Mid level ridging will persist over the Southeast through late week. Heigheights briefly weaken today as a shortwave passes by to the north, before rebuilding for Saturday. At the surface, high pressure will reside offshore with a trough inland. This pattern will continue to favor warm and dry conditions through Saturday. ECMWF (European Centre for Medium-Range Weather Forecasts) EFI for MaxT is sitting around 95-100% across most of the Southeast coast over the next two days, and highs in the lower to mid 90s this afternoon and again Saturday afternoon will put daily records in jeopardy (see climate section below). Additionally, the latest Drought Monitor indicates D4/Exceptional Drought over a small portion of interior southeast GA, with a recent expansion of the D3/Extreme Drought to encompass much of the remaining area. These persistent, very dry conditions combined with RH values dipping into the mid-20s ahead of the sea breeze this afternoon and Saturday afternoon are concerning from a fire weather standpoint, thought winds remain light to moderate are expected to keep the threat for rapid wildfire spread limited. KEY MESSAGE 2: Minor coastal flooding possible along the South Carolina coast with the evening high tides this weekend. The combination of the new moon (today) and perigee (Sunday) will bring elevated astronomical tidal ranges this weekend into early next week. Minor coastal flooding is possible with the Saturday evening high tide along the South Carolina coast. Tide levels will be elevated again with the Sunday evening high tide, but the coastal flooding threat is uncertain and dependent on the timing of the cold frontal passage during the day and the direction of the post-frontal winds. KEY MESSAGE 3: A cold front will bring low end rain chances Sunday, followed by a brief cooldown early next week. A mid level trough will swing into the eastern CONUS on Sunday, bringing an associated cold front with it. The greatest pre- frontal moisture convergence will generally remain north of the area, though at least a few showers and an isolated thunderstorm or two are possible mainly across the Lowcountry or Savannah River corridor. Significant rainfall remains unlikely, though probs have crept up a bit with the probability for 24 hr rainfall >0.10" now 15-25% across much of the area. Otherwise, temperatures following frontal passage will be notably cooler than previous days. Monday highs will be below normal before moderating towards the middle of the week. Lows are even expected to dip back into the 40s. Still no notable rain chances in the forecast for the remainder of next week. Marine Modest gradient enhancement in advance of an approaching but deteriorating cold front this morning is producing moderate winds across the waters. However, this gradient will weaken through the morning, with mainly light winds prevailing outside of the sea breeze corridor by this afternoon. Otherwise, quiet marine conditions will persist into Saturday with the region remaining along the western flanks of Atlantic high pressure centered well offshore. Sea breeze enhancements along the land/sea interface and Charleston Harbor are likely each afternoon/evening. A strong cold front is poised to push through the waters Sunday afternoon with winds quickly ramping up Sunday night into Monday morning in response to post-frontal cold air advection and a rapid tightening of the pressure gradient. North to northeast winds of 20- 30 kt are likely with gusts approaching gale force, especially over the 20-60 NM offshore zones. Seas look to peak Monday, ranging from 4-6 ft nearshore waters to 7-10 ft over the offshore waters (highest offshore Georgia waters). Small Craft Advisories are likely and a Gale Watch/Warning could be needed over the offshore zones. Rip Currents A Moderate Risk of rip currents remains in place for all beaches through Saturday due to the combination of 2-3 ft swell around 10 seconds, modest onshore flow, and increasing astronomical influences associated with lunar perigee/new moon. An elevated risk for rip currents will likely persist through the weekend and especially early next week as a pinched gradient associated with a passing cold front supports a gusty northeast wind event along the Southeast Coast. Climate Record High Temperatures: April 17: KCHS: 91/1967 KCXM: 86/2006 KSAV: 95/1967 April 18: KCHS: 92/1967 KSAV: 93/1967 NOAA Charleston SC Office: Watches - Warnings - Advisories GA...None. SC...None. Marine None. |
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