Hurricane Matthew has weakened slightly as it heads towards Jamaica and Cuba, but with winds reaching 250km/h forecasters say the storm is still powerful enough to wreck homes and islanders are bracing for its arrival.
Matthew, the strongest hurricane in the Atlantic Ocean since Felix in 2007, was forecast to make landfall as a major storm on Monday on Jamaica's southern coast, home to the country's capital, Kingston, and its only oil refinery. It could also affect tourist destinations such as Montego Bay in the north.
With Matthew about 675km southeast of Kingston, the US National Hurricane Center (NHC) downgraded its designation to a Category 4 from the top Category 5 on the Saffir-Simpson scale of hurricane intensity.
Rain fell on the Jamaican capital on Saturday and authorities said they were taking all possible precautions.
"The government is on high alert," said Robert Morgan, director of communications at the prime minister's office, which hosted an emergency meeting to plan for the storm on Friday.
Disaster coordinators, police and troops are on standby and shelters are being opened across the island, Morgan said.
Cuba declared the first stage of an emergency in five eastern provinces. In its second city, Santiago de Cuba, the ruling Communist Party opened shelters and organising volunteer teams to clean storm drains and gather food stocks.
Cuba has a solid track record of preparing for storms. The last big one to hit was Sandy in 2012, which though weaker than Matthew, caused major damage to property and killed 11 people.
The centre of Matthew will move away from the Guajira Peninsula early on Saturday, across the central Caribbean Sea on Saturday and approach Jamaica late on Sunday, the NHC said.
Jamaica was hard hit by hurricane Gilbert in 1988.
Matthew could be the most powerful storm to cross the island since records began, meteorologist Eric Holthaus said on Twitter.
Many Kingstonians stocked up on water and food on Friday.
Tenaj Lewis, 41, a doctor who was stocking up with groceries in Kingston on Friday, said Jamaica was much better-prepared for hurricanes than when Gilbert struck.
"The country literally shut down for months," she said.
Since then, hurricanes have brought a few days of power outages but have not been nearly as destructive and many Jamaicans were unflustered.
Southwest Airlines warned that flights to Montego Bay might be disrupted and said customers could reschedule.
On Monday, Matthew is forecast to skim past the southern coast of Haiti, prone to devastating flooding. Officials said preparation efforts were focused in the south.