Hurricane Melissa strengthened into a Category 4 storm on Sunday, unleashing torrential rain and threatening to bring catastrophic flooding to the northern Caribbean.

Hurricane Melissa is currently sustaining winds near 140 mph, and is expected to make landfall in Jamaica on Monday.

Tropical Storm Melissa is lumbering through the Caribbean Sea and bringing a risk of dangerous landslides and life-threatening flooding to Jamaica and southern Hispaniola.

Hurricane Melissa has strengthened into a major Category 4 hurricane and could grow further. As much as 40 inches of rain are forecast in parts of the northern Caribbean.

The National Hurricane Center in Miami warned of "life-threatening and catastrophic flash flooding and landslides" throughout Hispaniola.

Melissa has already turned deadly across Haiti and the Dominican Republic, but AccuWeather meteorologists warn that the worst may be yet to come with the storm on track to intensify.

A fast developing storm was expected to bring “unprecedented” amounts of rain to several countries, meteorologists said.

Tropical Storm Melissa is effectively parked in the central Caribbean, dumping devastating amounts of rain that has soaked Haiti and Jamaica, already claimed at least three lives and destroyed one bridge.