(CNN) -- Hurricane Otto will bring heavy rains that "could produce life-threatening flash floods and mud slides" in parts of the Caribbean on Friday night, the National Hurricane Center said.
Otto, a Category 1 storm, is expected to deluge the Virgin Islands, Puerto Rico, the eastern Dominican Republic and the northern Leeward Islands, the center said in its 5 p.m. Friday forecast.
The storm is about 410 miles (660 kilometers) southeast of Bermuda, moving toward the northeast at around 21 mph (34 kph), the center said.
Otto has maximum sustained winds of 80 mph (130 kph).
The storm is strengthening as it moves into the open Atlantic and could continue to do so until Sunday, when it is expected to weaken, the center said.