Tropical Storm Melissa lumbered through the Caribbean Sea on Thursday, bringing a risk of dangerous landslides and life-threatening flooding to Jamaica and southern Hispaniola — an island shared by the Dominican Republic and Haiti. Officials urged residents in flood-prone areas to seek higher ground.

The storm was blamed for downing a large tree that killed an elderly man in the coastal town of Marigot in southern Haiti, while five other people were injured in flooding in the central Artibonite area, according to the Civil Protection Agency.

The slow-moving storm was centered about 200 miles (320 kilometers) south-southeast of Kingston, Jamaica, and about 290 miles (470 kilometers) southwest of Port-au-Prince, Haiti. It had maximum sustained winds of 45 mph (75 kph) and was moving north-northwest at 2 mph (4 kph), the U.S. National Hurricane Center in Miami said.

A hurricane watch and tropical storm warning was in effect for Jamaica and the southwestern peninsula of Haiti.

“The system is still moving very slowly,” said Michael Brennan, the U.S. National Hurricane Center's director. “We are very concerned about the potential for multiple days of long duration wind, storm surge, heavy rainfall and flooding impacts.”

Melissa was expected to remain over open water this week, but move closer to Jamaica and southwestern Haiti in upcoming days. It was expected to strengthen significantly by late Friday and become a major hurricane by the end of the weekend, possibly reaching Category 4 status by Tuesday.

In Jamaica, officials said that 881 shelters would be made available as needed. Courts were ordered closed and schools were to switch to remote classes on Thursday. Meanwhile, crews placed 1,000 sandbags in the eastern part of Kingston to prevent flooding from a nearby gully.

Health Minister Christopher Tufton warned that Jamaica’s 325 health centers would close by Thursday afternoon, and that the storm could interrupt supply chains, including those of life-saving medication.

Jamaica's government warned of upcoming power outages and noted it has already flown in dozens of additional line workers to help in the storm's aftermath.

Forecasters said Jamaica's eastern region could see up to 12 inches (30 centimeters) of rain that could lead to flooding and landslides because the ground is already saturated from recent heavy rains unrelated to the storm.

More than 100 people remained sheltered in the Dominican Republic, where schools, businesses and government agencies were closed in the nine provinces under alert. Dozens of water supply systems remained out of service on Thursday, affecting more than half a million customers. The storm also downed trees and traffic lights and unleashed a couple of small landslides.

The U.S. National Hurricane Center in Miami warned that “significant, life-threatening flash flooding and numerous landslides" were expected in Jamaica and southern Hispaniola.

Storm sparks concern for Haiti

Melissa is the 13th named storm of the Atlantic hurricane season, and the first named storm to form in the Caribbean this year..

AP Video shot by Martin Adames and Raphael Simon