Season's 1st Atlantic tropical storm forms off S.Carolina

MIAMI May 19 (Reuters) - Tropical Storm Alberto formed off the South Carolina coast on Saturday, bringing an early start to the Atlantic hurricane season, forecasters at the U.S. National Hurricane Center said.

Alberto had top sustained winds of 45 miles per hour (75 kph) and was in the Atlantic about 140 miles (225 km) east-southeast of Charleston. It was moving slowly southwest and forecasters said a storm watch might be posted later on Saturday for part of the North and South Carolina coast.

(Reporting By Jane Sutton; Editing by Peter Cooney)