Updated 11:58 PM ET
(AP) RALEIGH, N.C. - Forecasters late Saturday issued a tropical storm watch for parts of the South Carolina coast after the first tropical storm of the 2012 hurricane season formed in the Atlantic.
The National Hurricane Center in Miami issued the watch after Tropical Storm Alberto formed Saturday. The official start to hurricane season is June 1, but tropical storms occasionally occur before then.
The advisory covers the South Carolina coast from the Savannah River to the South Santee River for at least the next 24 hours. Tropical storm and dangerous surf conditions are possible.
Late Saturday, the storm was 110 miles (177 kilometers) southeast of Charleston, S.C. with maximum sustained winds of 50 mph (80 kph). It was moving southwest at 6 mph (10 kph).
Forecasters advised coastal interests from Georgia to North Carolina's Outer Banks to track the storm.
The hurricane center said a decrease in speed was expected through Sunday, with the storm turning toward the west-northwest and then moving north-northeast by Monday. Tropical storm-force winds extend outward up to 45 miles (72 kilometers).
National Weather Service meteorologist Sandy LaCorte in Wilmington said early Saturday evening the system is expected to reverse course and head northeast over the next several days. She said the center of the storm is not expected to get close to the Carolinas' coast.
LaCorte said Alberto will produce increased waves at beaches in the Carolinas. There is a high risk of rip currents along North Carolina's Outer Banks, and a moderate risk along the southeastern beaches and the entire South Carolina coast. Winds will gust to around 25 mph.
The weather service said there will be isolated and scattered rain showers along the coast of the Carolinas into early next week.
A forecast map by the hurricane center predicts that the storm will drift toward the open sea off the Mid-Atlantic region by midweek, but it's difficult to accurately predict a storm's path days in advance.