Tropical Storm Ernesto: 3-day forecast track. NOAA/NHC graphic

At 11 p.m. EDT, the center of the storm was 260 miles south-southeast of Santo Domingo, Dominican Republic, and 555 miles east-southeast of Kingston, Jamaica, moving west-northwest at about 16 mph, the National Hurricane Center reported. The storm is expected to pass the southern coast of Hispaniola on Saturday, and Haiti had posted a storm warning for the southern coast while Jamaica posted a storm watch.

Forecasters warned that there is a chance Ernesto, with top sustained winds of about 45 mph at 11 p.m., could become much stronger over the Caribbean.

Ernesto is the fifth named storm of the Atlantic hurricane season and the first that poses a threat to land. At this time last year, there had been twice as many tropical storms and hurricanes and Katrina was within a few days of slamming into New Orleans.

Out in the Atlantic on Friday, Tropical Storm Debby was almost 1,500 miles west-northwest of the Cape Verde Islands and heading northwest at 17 mph.