The storm was forecast to dump up to 25 inches of rain over Haiti, the Dominican Republic and Jamaica as it continues to strengthen this weekend.

U.S. forecasters issued a hurricane warning for Jamaica Saturday as Storm Melissa reached hurricane strength, threatening catastrophic flooding in the northern Caribbean. A hurricane warning means winds of at least 74 mph (119 kph) are expected in the area within 36 hours.

Haiti is expected to see catastrophic flash floods and landslides early next week causing “extensive infrastructural damage and potentially prolonged isolation of communities.” The southwestern peninsula of Haiti, from the border of the Dominican Republic to Port-au-Prince, was placed under a hurricane watch and a tropical-storm warning.

Hurricane Melissa is heading for the northern Caribbean but will spare Louisiana. The storm has already killed at least three people in Haiti and one in the Dominican Republic.

Melissa strengthened into a hurricane southeast of Jamaica and is set to rapidly grow, raising the risk for catastrophic flooding and wind damage across Jamaica and the Caribbean, where the storm has already killed at least four people.

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.

Why meteorologists are so concerned about Tropical Storm Melissa when it becomes a hurricane near Jamaica, Haiti, the Cayman Islands, and Cuba.

Jamaica's central location in the Caribbean, the island has never recorded a direct landfall from a Category 4 or 5 hurricane, according to records from the National Hurricane Center (NHC) dating back to 1850.

Melissa is expected to significantly strengthen by late Friday and over the weekend, when the storm could become a hurricane as early as Saturday.