The US National Hurricane Center in Miami said Matthew’s winds had slipped slightly from a peak of 160 mph (260 kph) to a still-potentially devastating 150 mph (240 kph) and it was expected to near eastern Jamaica and southwestern Haiti on Monday.
The forecast track would carry it across Cuba and into the Bahamas, with an outside chance of a brush with Florida, though that would be several days away.
“It’s too early to rule out what impacts, if any, would occur in the United States and Florida,” said Dennis Feltgen, a spokesman at the Hurricane Center.
As Matthew skimmed past the northern tip of South America there were reports of at least one death – the second attributed to the storm.
In Jamaica, high surf began pounding the coast and flooding temporarily closed the road linking the capital to its airport. Carl Ferguson, head of the marine police, said people were starting to heed calls to relocate from small islands and areas near rural waterways.
Jamaicans, crowded supermarkets to buy bottled water, canned food and batteries, and there was already flooding in the coastal town of Port Royal, where officials are urging residents to seek refuge in government shelters once they open up on Sunday.
Many Jamaicans also began stocking up for the emergency.
“I left work to pick up a few items, candles, tin stuff, bread,” 41-year-old Angella Wage said at a crowded store in the Half-Way Tree area of Kingston. “We can never be too careful.”
Feltgen said storm force winds and rain will arrive well before the center of the storm. Jamaicans “basically have daylight today, they have tonight and they have daylight tomorrow to take care of what needs to be done,” he said.
Jamaicans are accustomed to intense storms, but Hurricane Matthew looked particularly threatening. At its peak, it was more powerful than Hurricane Gilbert, which made landfall on the island in September 1988 and was the most destructive storm in the country’s modern history.
The US Navy base at Guantanamo Bay, Cuba, is also potentially in the path of the storm. A mandatory evacuation of non-essential personnel, including family members of military personnel was underway and everyone remaining behind was being told to take shelter, said Julie Ann Ripley, a spokeswoman. There are about 5,500 people living on the base, including 61 men held at the detention center.
Forecasters said rainfall totals could reach 10 to 15 inches (25 to 38 centimeters) with isolated maximum amounts of 25 inches (63 centimeters) in Jamaica and southwestern Haiti.
On Saturday afternoon, authorities issued a hurricane warning for much of Haiti and said it could bring life-threatening rainfall to portions of the impoverished Caribbean country.