Charleston Harbor Marine Forecast
| Tonight...Sw Winds 5 To 10 Kt, Becoming N With Gusts To 20 Kt Late This Evening, Then Increasing To 15 Kt With Gusts To 25 Kt After Midnight, Becoming Ne With Gusts To 25 Kt Late. Waves 1 To 2 Ft. A Slight Chance Of Showers And Tstms Early This Evening, Then A Chance Of Showers And Tstms Late This Evening. |
| Tue...Ne Winds 15 To 20 Kt With Gusts To 35 Kt. Waves 1 To 2 Ft. |
| Tue Night...Ne Winds 15 To 20 Kt, Diminishing To 10 To 15 Kt After Midnight. Waves 1 To 2 Ft. |
| Wed...Ne Winds 10 Kt With Gusts To 20 Kt. A Slight Chance Of Showers. |
| Wed Night...Ne Winds 5 To 10 Kt. |
| Thu...Variable Winds 5 Kt. |
| Thu Night...S Winds 5 Kt. |
| Fri...Sw Winds 5 To 10 Kt. |
| Fri Night...Sw Winds 10 To 15 Kt. |
| Sat...Ne Winds 15 Kt. |
| Sat Night...Ne Winds 10 To 15 Kt. Winds And Waves Higher In And Near Tstms. Unless Otherwise Noted, Waves 1 Foot Or Less. Charleston Harbor Water Temperature 61 Degrees. |
| Area Forecast Discussion National Weather Service Charleston SC 247pm EDT Monday Mar 23 2026 .WHAT HAS CHANGED... The Aviation Section has been updated for the 18Z TAF issuance. All Key Messages and sections have been updated. .KEY MESSAGES... - 1) A strong backdoor cold front will move through this evening, bringing isolated thunderstorms this evening along with breezy winds and cooler conditions tonight into Tuesday. - 2) Near-record warmth possible Friday before a cold front brings cooler conditions this weekend. KEY MESSAGE 1: A strong backdoor cold front will move through this evening, bringing isolated thunderstorms this evening along with breezy winds and cooler conditions tonight into Tuesday. As of noontime today a strong backdoor cold front was analyzed just east of the Appalachian Mountains in the Carolinas, extending northeastward into the Mid-Atlantic. As this front progresses southward a line of showers and possibly a thunderstorm is expected to work its way southward across the forecast area. Showers could begin impacting northern Berkeley County as early as 5pm this evening, with showers/tstorms diminishing as they approach our SE GA counties. While the environment is supportive of thunder, there is little support for severe thunderstorms. However, given roughly 500 J/kg of ML CAPE around 25 knots of Effective Bulk Shear, a stronger thunderstorm cannot be ruled out, with damaging wind gusts the main threat. Outside of any convection, breezy conditions are expected tonight into Tuesday as surface high pressure builds in from the north behind the front. Inland locations could experience gusts up to 25 mph, while coastal areas are likely to see the strongest winds. Beach locations could experience gusts of 30-35 mph, with a few spots potentially reaching near 40 mph, coming off the ocean. Over Lake Moultrie winds will strengthen with frequent gusts around 20 kt. Gusts could reach 25 kt, particularly following the initial frontal passage late this evening, but a Lake Wind Advisory was withheld due to the short-lived conditions. As cooler high pressure filters in from the north and cold air advection intensifies after midnight, temperatures will drop tonight, with lows forecasted in the upper 40s across interior southeast South Carolina counties and in the lower to middle 50s farther south. Tuesday's highs will be cooler, reaching the lower to middle 60s across the Lowcountry and upper 60s across southeast Georgia. Northern Berkeley County and areas along the Charleston coast may struggle to reach 60 degrees. Despite this noticeable cool- down, temperatures will align more closely with seasonal norms. KEY MESSAGE 2: Near-record warmth possible Friday before a cold front brings cooler conditions this weekend. A broad trough aloft will shift offshore Thursday, allowing heigheights to rise and permitting a brief rebound in temperatures above climatological norms. Forecasted highs Friday are expected to be in the mid to upper 80s, potentially challenging existing records (see Climate section). Following this warm period, a cold front is expected to push through Friday night into Saturday, ushering in significantly cooler conditions. Overnight lows could even drop into the upper 30s across northern interior counties, including Berkeley, Dorchester, and Colleton. Cooler conditions are expected for the weekend, with highs in the 60s. Although more confident in the cooler conditions, model guidance remains uncertain regarding the potential for showers or thunderstorms with the frontal passage. Marine Conditions across the marine waters will quickly deteriorate this evening as a strong backdoor cold front pushes southward across the marine waters. The combination of cooler temperatures and a tightening pressure gradient will yield gusty NE winds to Gale Force (outside of the Charleston Harbor) and building seas. A Gale Warning is in effect for all coastal waters outside of the Charleston Harbor, where a Small Craft Advisory is in effect. Tuesday through Saturday: Gusts will likely peak Tuesday morning around 30 to 35 kt. Gale Warnings for all marine zones will continue into Tuesday evening, in addition to the Small Craft Advisory for the Charleston Harbor. Wave heigheights will peak Tuesday afternoon, reaching 6-9 ft within 20 nm and 9-11 ft across the Georgia offshore waters (from 20-60 nm). High pressure building into the region and a relaxing pressure gradient Tuesday night should lead to diminishing winds and gradually subsiding seas, although 6 ft waves will persist over the outer Georgia waters into Wednesday night. Conditions could then deteriorate near the end of the period as another strong cold front approaches. Climate Record High Temperatures: March 23: KCHS: 87/1995 March 27: KCHS: 87/2021 KCXM: 81/2021 KSAV: 89/2021 NOAA Charleston SC Office: Watches - Warnings - Advisories GA...None. SC...None. Marine Small Craft Advisory from 2am to 11pm EDT Tuesday for AMZ330. Gale Warning from 11pm this evening to 11pm EDT Tuesday for AMZ350-352. Gale Warning from 2am to 11pm EDT Tuesday for AMZ354. Gale Warning from 11pm this evening to 2am EDT Wednesday for AMZ374. |
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