Hurricane Melissa maintained its powerful Category 4 strength on Sunday as it drifted slowly toward Jamaica, forecast to bring “catastrophic” flash flooding and landslides to the Caribbean nation.

Tropical Storm Melissa has strengthened into a hurricane and is expected to become a major hurricane by the end of the weekend, the U.S. National Hurricane Center said on Saturday.

Melissa could bring total rainfall of 15 to 25 inches (38 to 64 cm) in portions of southern Hispaniola and Jamaica, the NHC said, with isolated areas receiving as much as 35 inches.