Hurricane Matthew rapidly gained power Friday, escalating to a powerful Category 4 storm as it moved over the open Caribbean south of Jamaica, US forecasters said.
A hurricane watch was issued for Jamaica due to the approaching storm, and forecasters warned of tropical storm conditions for Haiti and Cuba in the next two days.
Packing wind speeds of 140 miles (220 kilometers) per hour, the storm moved in a western direction about 465 miles southeast of Jamaica.
"Some additional strengthening is possible tonight," said the National Hurricane Center.
"Matthew is expected to remain a powerful hurricane through Sunday."
The hurricane watch issued for Jamaica indicates that hurricane conditions are possible in the next 48 hours.