← Coast Conditions

Guide

Small craft advisories on the Georgia coast

Checked October 8, 2026 against the National Weather Service offices in Charleston and Jacksonville, their coastal waters forecasts, and the National Weather Service’s marine directives.

The Marine tile repeats the National Weather Service’s coastal waters forecast for the water off your town. On this coast that is the open Atlantic out twenty miles, forecast by one of two offices, and the sounds and tidal rivers behind the barrier islands read the same zone. This page explains which zone each town reads, how to read the forecast, and what the advisories and warnings mean in knots and feet.

Two offices, Tybee Island to St. Marys

The weather service office in Charleston writes the coastal waters forecast for the water from the South Santee River in South Carolina to Altamaha Sound, which it heads “South Santee River SC to Altamaha Sound GA out 60 NM, including Charleston Harbor and Grays Reef National Marine Sanctuary”, several times a day. The office in Jacksonville writes it from Altamaha Sound south past the Florida line, about every six hours. Altamaha Sound is the line between the two boards as well: Chatham, Bryan, Liberty and McIntosh counties read Charleston’s zone, Glynn and Camden read Jacksonville’s.

Savannah and the Georgia coast

ZoneNameOfficeTowns on this coast
AMZ364Coastal waters from Savannah GA to Altamaha Sound GA out 20 nm, including Grays ReefCharlestonTybee Island, Savannah, Thunderbolt, Wilmington Island, Skidaway Island, Richmond Hill, Midway, Sunbury, Darien, Sapelo Island

The Golden Isles

ZoneNameOfficeTowns on this coast
AMZ450Coastal waters from Altamaha Sound to Fernandina Beach FL out 20 NMJacksonvilleBrunswick, St. Simons Island, Sea Island, Jekyll Island, Woodbine, Kingsland, St. Marys, Cumberland Island

Beyond the twenty-mile line are the twenty-to-sixty-mile zones, Charleston’s AMZ384 and Jacksonville’s AMZ470; the board reads the nearshore zone only. Charleston’s AMZ362, Edisto Beach to Savannah, is the water north of the Savannah River entrance, off South Carolina.

The sounds and rivers have no zone of their own

Neither office writes a separate forecast for Wassaw, Ossabaw, St. Catherines, Sapelo, St. Simons or Cumberland Sound, or for the Savannah, Ogeechee, Altamaha, Satilla and St. Marys rivers, the way Charleston writes one for Charleston Harbor. A town up a river, like Savannah, Richmond Hill, Darien, Woodbine or Kingsland, reads the ocean zone off its own stretch of coast. Read it for the wind; the seas it gives are for the open water outside the inlets, and inside, the state of the water is the wind against the tide, which the forecast does not say.

Reading the forecast

Each period gives the wind by direction and speed in knots, the seas in feet, and often a Wave Detail line after them: each wave train by direction, height and period in seconds. A short period means close-set waves, steeper for their height. When two zones are expected to see the same weather the office writes one paragraph headed with both names, and when they differ, each gets its own. Charleston’s forecast also carries a water temperature line for Charleston Harbor; Jacksonville’s names the inlets in its synopsis when they are rough.

What the words mean, in knots

These are the National Weather Service’s thresholds. The advisory threshold depends on the region, and the two offices on this coast sit in different regions; the warning thresholds do not change.

The line most often misread

A forecast of seas is a significant wave height: the average height of the highest third of the waves. So “seas 4 to 6 feet” is not the size of every wave; most are smaller, and some are bigger.

The weather service’s caution: wave forecasts are an average, and some individual waves “can be expected to be as much as two times greater.”

Read a forecast of six-foot seas as one that can include twelve-foot waves. And at every inlet on this coast, an ebb tide running out against an onshore wind stands the waves up at the bar; the forecast’s seas are for outside it.

Sources