KINGSTON - Hurricane Melissa, already a major category 4 storm, gathered steam as it took aim at Jamaica and other parts of the Caribbean, with forecasters predicting catastrophic flooding and urging residents to seek shelter immediately.
Melissa has already been blamed for at least four deaths in Haiti and the Dominican Republic this week, as its outer bands brought heavy rains and landslides.
The storm is moving at a worryingly slow pace -- just seven kilometres an hour -- meaning areas in its path could see punishing conditions for far longer than a hurricane that passes by more quickly.
The US National Hurricane Center (NHC) said Melissa was packing maximum winds of about 230km/h -- and would likely intensify into a top-level category 5 storm later Sunday.
Up to about a metre of rainfall could hit parts of Jamaica, Haiti and the Dominican Republic, sparking flash flooding and more landslides.
"This extreme rainfall potential, owing to the slow motion, is going to create a catastrophic event here for Jamaica," NHC Deputy Director Jamie Rhome said in a webcast briefing.
"You need to just be wherever you're going to be and be ready to ride this out for several days," Rhome said.
"Conditions will deteriorate really, really rapidly here in the next few hours. Don't be out and about after sunset."