Dorian, with maximum sustained winds of 50 miles (80 kilometers) per hour, was about 1,425 miles east of the northern Leeward Islands and moving west-northwest at 20 mph, according to a center advisory before 5 a.m. in New York.
“Slow weakening is expected during the next day or so,” according to the advisory. The storm is forecast to turn toward the west with an increase in forward speed through Saturday. The center’s five-day projection has Dorian passing north of or over Puerto Rico on July 29.
Dorian is the fourth tropical storm of the Atlantic hurricane season, which runs from June 1 through Nov. 30. From 1966 to 2009, the fourth system typically formed by Aug. 23, according to the hurricane center.