Tropical Storm Sam forecast to form Thursday and strengthen into a major hurricane within days

Tropical Depression Eighteen, which is forecast to become the 18th named storm of the season, was moving west at 15 mph with maximum sustained winds of 35 mph, as of 5 a.m. Thursday, about 1,860 miles east-southeast of the boundary where the Atlantic Ocean meets the far eastern Caribbean Sea. It is forecast to move west-northwest by Friday.