RALEIGH, N.C. — The first tropical storm of the hurricane season has formed off the coast of South Carolina with top winds of 60 mph (97 kph), but it isn't threatening land.

Forecasters said early Saturday evening that Tropical Storm Alberto was centered about 130 miles (209 kilometers) east of Charleston, S.C.

No coastal watches or warnings were in effect, but forecasters said they may have to issue one later for the Carolinas coast.

The Miami-based National Hurricane Center said there were no hazards affecting land so far, and the tropical-strength winds weren't reaching shore. Forecasters said Saturday evening that a ship near the center of Alberto measured winds about 15 mph stronger than originally reported.

National Weather Service meteorologist Sandy LaCorte in Wilmington said the center of the storm is not expected to get close to the Carolinas' coast.