The National Hurricane Center says Tropical Storm Bonnie has formed off South Carolina, strengthening from a tropical depression. Forecasters detected 40 mph winds in the storm Saturday afternoon, making it the season's second-named tropical storm, four days before the official start of hurricane season in the Atlantic Ocean, the AP reports. The storm was about 125 miles from Charleston and moving toward the coast at 10 mph.
Forecasters expect Bonnie to move onshore south of Charleston sometime Sunday morning, then turn northeast and slowly dissipate as it moves along the coast of the Carolinas over the rest of the Memorial Day holiday weekend. Heavy rains have already begun falling along the South Carolina coast. Forecasters say the worst of the rain and winds are ahead of the center of the tropical storm. No evacuations have been ordered. (Read more tropical storms stories.)