SHARECOMMENTMORE

MIAMI -- The first tropical storm of the season has formed off the coast of South Carolina with top winds of 45 mph (75 kph).

Forecasters say tropical storm Alberto was centered about 140 miles (225 km) east Charleston, S.C., on Saturday afternoon.

No coastal watches or warnings were in effect, but forecasters say they may issue one later.

The hurricane center says there were no hazards affecting land so far, and the tropical-strength winds weren't reaching shore. Some strengthening was possible.

It was moving about 3 mph (6 kph) to the southwest.

The official start to hurricane season is June 1, but tropical storms often occur before then.