Haiti on Wednesday issued a red alert in advance of the arrival of Tropical Storm Chantal, which was due to lash the impoverished Caribbean island later on Wednesday.
Officials cancelled domestic air traffic, as well as flights to the United States, as the storm bore down on Haiti packing winds of some 45 miles (75 kilometers) per hour.
"Populations living in zones at risk should take shelter," said Alta Jean-Baptiste, head of Haiti's civil defense office, who warned of a risk of landslides and floods.
At 1500 GMT, Chantal was 145 miles (235 kilometers) south of Port au Prince, the Miami, Florida-based National Hurricane Center said.
The storm was expected to hit the island of Hispaniola -- shared by Haiti and the Dominican Republic -- before moving between eastern Cuba and Jamaica later Wednesday, and to the Florida Straits on Thursday, the NHC said.
Haiti, the poorest nation in the hemisphere, has about 10 million inhabitants, about the same population as the Dominican Republic.
The country is still struggling to recover from a January 2010 earthquake that killed 250,000 people.
Torrential rains and tropical storms can be deadly in rainy season.
Heavy rain picks up speed on slopes and can wash away riverside communities. It is a major concern in the region, especially in Haiti, where soil erosion is a longstanding problem.