After being slammed by Irma, Caribbean islands brace for Hurricane Jose

— -- Less than a week after being slammed by Hurricane Irma, tiny Caribbean islands are bracing for a new threat: Hurricane Jose.

Jose, which was upgraded to a Category 4 hurricane Friday -- and remained so on Saturday morning -- with 150 mph winds, is following Irma's path and is forecast to come close to, but not directly hit, the Leeward Islands, including St. Martin and Barbuda. Jose is not currently a threat to the U.S.

As of 5 a.m. Saturday, Jose was 190 miles east-southeast of the northern Leeward Islands. Hurricane warnings were in effect for St. Martin, St. Barts, Antigua and Barbuda, and St. Kitts. A tropical storm watch was in effect for the British Virgin Islands.

Thousands of Americans are believed to be stranded on St. Martin, the U.S. Consulate General in Curacao said, according to The Associated Press. Damage to the island was extensive, with many homes left destroyed and power completely cut off, the AP reported. The damage on St. Martin is so bad that some large resort companies, including Sonesta, have canceled reservations for the rest of 2017. And with a second hurricane nearing, it will be several more days before the island receives any aid.

On Thursday, Antigua and Barbuda Prime Minister Gaston Browne urged residents of Barbuda, where an estimated 95 percent of structures and vehicles were destroyed by Irma, to evacuate to nearby Antigua as Jose approached. By Friday, the government said it had brought all 1,800 or so of its residents to its sister island to weather the impending storm.

Browne described the damage to Barbuda from Irma as "horrible," saying the storm ripped into the island with the force of a "bomb" going off.

Meanwhile, Irma is advancing on the U.S. mainland and is now forecast to hit the Florida Keys as a Category 5 storm. Meteorologists expect Irma to make landfall in the Keys between 5 a.m. and 7 a.m. ET on Sunday. Overnight projections of Irma's path showed less of a threat to the Carolinas as the monster storm appeared likely to move directly up the middle of Florida and curve inland.

According to the AP, at least 20 people have died as a result of Irma.

Irma leaves path of destruction

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A girl rests her head on a set of towels supplied by the American Red Cross at a makeshift shelter, after arriving in San Juan, Puerto Rico, Sept. 14, 2017, on a cruise ship with families evacuated from Caribbean islands devastated by Hurricane Irma.

Ricardo Arduengo/AP