Tropical Storm Arthur could bring rain around sunrise Thursday, but the chance is small because of the buildup of dry air along the storm's western edge, according to National Weather Service meteorologist Bob Bright.
The tropical storm is expected to pass about 130 miles off the county's coast, Bright added.
Rough surf is expected but should dissipate by Thursday evening, Bright said. Waves are expected to be five feet, and rip currents will be stronger than normal, he said.
Kevin Osterstock, battalion chief for the Town of Hilton Head Island Fire & Rescue Division, said two groups of swimmers with rafts got caught in rip currents Wednesday off Folly Field Beach. Members of Shore Beach Service swam out and helped them to shore, he said.
Osterstock urged beachgoers who become stuck in rip currents to swim parallel to the shore, rather than toward it.
"They end up getting pulled out to sea, and they panic and try to swim back to the beach, when really, what they need to do is swim parallel," he said.
States north of South Carolina are bracing for the storm as it continues up the East Coast. North Carolina issued a hurricane warning Wednesday for coastal sections.
Local American Red Cross volunteers and resources are also being readied for deployment to other states for relief work, depending on the storm's severity, according to a Red Cross news release.
Follow reporter Matt McNab at twitter.com/IPBG_Matt.