Hurricane Irma is likely to be downgraded to a category-four storm by the time it makes landfall in Florida, the US National Hurricane Center says.
Irma, at present a category-five storm packing maximum sustained winds of 290km/h, is moving off the northern coast of the Dominican Republic.
It has become a little less organised during the past few hours but the threat of direct hurricane impacts in Florida at the weekend and early next week continues to increase, the NHC says.
Hurricane watches are in effect for the northwestern Bahamas and much of Cuba.
Irma, one of the most powerful Atlantic storms in a century, killed eight people on the Caribbean island of Saint Martin and left Barbuda devastated on Thursday.
Meanwhile, a hurricane swirling in the Gulf of Mexico, Katia, which is about 310km northeast of Veracruz with maximum sustained winds of 130km/h, is likely to gain near major hurricane strength by landfall, the NHC said.
A third hurricane in the Atlantic, Jose, has strengthened slightly and is expected to intensify further during the next 48 hours.
Hurricane Jose is about 1310km east of the Lesser Antilles, with maximum sustained winds of 150km/h.
