Savannah, GA to Altamaha Sound, GA including Grays Reef National Marine Sanctuary Marine Forecast
| This Afternoon...Ne Winds 25 Kt With Gusts To 30 Kt. Seas 5 To 7 Ft. Wave Detail: E 7 Ft At 8 Seconds And E 2 Ft At 14 Seconds. A Slight Chance Of Showers. |
| Tonight...Ne Winds 20 To 25 Kt With Gusts To 30 Kt. Seas 5 To 7 Ft, Subsiding To 4 To 6 Ft After Midnight. Wave Detail: E 7 Ft At 7 Seconds And E 3 Ft At 14 Seconds, Becoming E 6 Ft At 7 Seconds And E 3 Ft At 14 Seconds. A Slight Chance Of Showers. A Slight Chance Of Tstms After Midnight. |
| Sat...Ne Winds 20 To 25 Kt. Seas 5 To 7 Ft, Building To 6 To 7 Ft In The Afternoon. Wave Detail: E 6 Ft At 7 Seconds And E 4 Ft At 13 Seconds, Becoming E 7 Ft At 7 Seconds And E 3 Ft At 13 Seconds. A Slight Chance Of Showers. A Slight Chance Of Tstms In The Morning, Then A Chance Of Tstms In The Afternoon. |
| Sat Night...E Winds 20 To 25 Kt. Seas 7 To 8 Ft, Subsiding To 6 To 8 Ft After Midnight. Wave Detail: E 8 Ft At 7 Seconds And E 2 Ft At 13 Seconds, Becoming E 7 Ft At 8 Seconds. A Chance Of Showers And Tstms. |
| Sun...E Winds 20 To 25 Kt. Seas 6 To 7 Ft, Building To 6 To 8 Ft In The Afternoon. Wave Detail: E 7 Ft At 8 Seconds, Becoming E 8 Ft At 8 Seconds And E 1 Foot At 14 Seconds. A Chance Of Showers And Tstms. |
| Sun Night...E Winds 20 To 25 Kt. Seas 7 To 8 Ft. Wave Detail: E 8 Ft At 8 Seconds And E 1 Foot At 14 Seconds. A Chance Of Tstms. A Chance Of Showers. |
| Mon...E Winds 20 To 25 Kt. Seas 7 To 8 Ft. A Chance Of Showers With A Slight Chance Of Tstms. |
| Mon Night...E Winds 20 To 25 Kt. Seas 6 To 8 Ft. A Chance Of Showers. |
| Tue...E Winds 15 To 20 Kt. Seas 5 To 7 Ft. A Chance Of Showers. |
| Tue Night...E Winds 15 To 20 Kt. Seas 5 To 6 Ft. A Slight Chance Of Showers. Winds And Seas Higher In And Near Tstms. |
| Area Forecast Discussion National Weather Service Charleston SC 217pm EDT Fri Oct 3 2025 Synopsis A strong high pressure will extend across the region into the weekend, with rain chances increasing on Sunday into early next week. A strong cold front will likely cross the area later next week. Near Term - Through Tonight Tonight: Overall, the pattern will remain the same with high pressure still centered to the north stretching across the Mid Atlantic region. This will maintain persistent northeast flow across the area with a subtle coastal trough positioned offshore. There are some indications in the hi-res guidance that this trough will shift a bit closer to shore overnight, potentially allowing shower activity to brush more of the coast overnight. Still, the bulk of the shower activity should remain over the coastal waters and the trajectory of the flow will highlight the GA coast as having the best rain chances through the overnight. Rainfall amounts along the GA coast should be a few hundredths in most areas, though the further south you go closer to the Altamaha there could be some amounts upwards of one or two tenths. Temperatures aren't expected to be quite as cool as they were the previous night, with lows more in the low to mid 60s for most locations. Short Term - Saturday Through Monday Upper level ridge holds tight across the eastern CONUS this weekend, as a surface high pressure gradually pushes eastward across North Carolina into the Atlantic. As noted in the previous discussion, an inverted coastal trough will keep NE to E flow in place for much of Saturday. While forcing remains quite meager, latest CAMs continue to support chances for showers offshore during the afternoon and evening, with perhaps a few pushing inland across southeastern Georgia. Nonetheless, with a decent amount of dry air to work with in the lower levels, not expecting to see much in the way of significant rainfall. The inverted trough continues to linger along the coast Sunday, which combined with increasing 850mb moisture and an advancing coastal low will result in a more unsettled pattern heading into Monday. That being said, latest guidance has started to shift the overall axis of heavy rainfall a bit southward, where the better instability and vorticity exist. Could certainly still see things shift over the next few forecast cycles, but for now, latest NBM run has decreased Probability of Precipitation across our area both Sunday and Monday. Now have Probability of Precipitation ranging between 20 to 60 percent across our area, with the greatest threat (50-60% PoPs) south of Savannah. Total Sunday and Monday rainfall accumulations of 2 to 4 inches are well within reason for coastal areas from Beaufort County southward, including the Savannah Metro area, with localized/reasonable worst case scenario amounts reach up to 5 inches. Long Term - Monday Night Through Friday Upper ridging builds modestly Tuesday before a series of shortwaves potentially move through mid-to-late next week. At the surface, high pressure shifts over Bermuda Tuesday, ridging into our area from the west into midweek, with only low-end precipitation chances. Then, by late week, very strong high pressure building over the Northeast is expected to force a strong backdoor cold front down the eastern seaboard as a CAD-like setup takes hold Thursday into Friday. The most impactful aspect of this forecast could end up being the good agreement on NE winds - 25th to 75th percentile reflecting a most likely wind speed along the coast of around 20-30 mph - to end the workweek, which, in addition to already elevated tide level, could bring a period of very impactful tidal flooding. See coastal flooding section for more. Marine Tonight: High pressure will remain centered to the north which will maintain persistent northeast flow within a tight pressure gradient. This will keep elevated winds and seas going through the overnight. Winds should peak in the evening with speeds expected to be 15-25 knots with frequent gusts into the 25-30 knot range. These speeds could diminish a bit through the late night hours as the gradient relaxes. Within Charleston Harbor, winds should mostly top out in the 15-20 knot range. Seas will peak in the evening with 4-7 ft common across the nearshore waters and 6-9 ft in the outer waters. Then by very late tonight, seas could drop off to be 4-6 ft in the nearshore waters and 5-8 ft in the outer waters. Regardless, conditions will remain supportive of Small Craft Advisories for all waters outside Charleston Harbor. Saturday through Tuesday: High pressure ridging inland and inverted coastal troughing off the coast continue breezy N to NE winds through the weekend. Winds trend more E early next week as high pressure moves further off the Mid-Atlantic coast, but a very long eastern fetch is likely to keep hazardous seas in place into mid-week despite winds trending more moderate. Rip Currents A high risk of rip currents will continue through Sunday in primarily medium period E to NE swells. High Surf Advisory remains in place through Saturday, though lower confidence in 6+ ft breaking waves still exist Saturday night into Sunday. Will continue to monitor trends and extend headlines as needed. Tides / Coastal Flooding A Coastal Flood Advisory has been issued for the upcoming afternoon high tide at Charleston. Tidal departures remain high and with the astronomical high tide being at 6.05 ft MLLW, we should get up into a range of 7.1-7.3 ft MLLW. Heading into this weekend and early next week, astronomical tides will increase due to the upcoming Full Moon (Oct 7) and Perigee (Oct 8). This in combination with the anticipation of continued northeasterly flow will cause the possibility of coastal flooding to become more likely along the entire coastline, including both Downtown Charleston and Fort Pulaski. Saltwater inundation could then occur during both the morning and evening high tide cycles during this time. Although there is considerable uncertainty this far out, persistent favorable winds have the potential to produce up to major coastal flooding by the latter part of next week. NOAA Charleston SC Office: Watches - Warnings - Advisories GA...High Risk for Rip Currents through Saturday evening for GAZ117-119- 139-141. High Surf Advisory until 8pm EDT Saturday for GAZ117-119-139- 141. SC...High Risk for Rip Currents through Saturday evening for SCZ048>051. High Surf Advisory until 8pm EDT Saturday for SCZ048>051. Coastal Flood Advisory until 8pm EDT this evening for SCZ049- 050. Marine Small Craft Advisory until 2pm EDT Tuesday for AMZ350-352-354. Small Craft Advisory until 6am EDT Wednesday for AMZ374. |
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