Tropical Storm Isaac strengthened yesterday as its rains took aim at flood prone Haiti, but it is not expected to become a hurricane until it moves into the Gulf of Mexico early next week.
On its current path, forecasters say Isaac will hit Cuba and the southern tip of Florida, putting the entire coast of south Florida under tropical storm watch on Friday.
Life-threatening flash floods and mudslides, which are common in Haiti, could add to the misery of 350,000 people still living in tent cities and camps after the January 2010 earthquake that killed more than 250,000 people.
The storm prompted Haitian President Michel Martelly to was cancel a planned trip to Japan.
"I know your worries," Martelly said in an address to the nation. "I also know we're a strong people."
About 3,000 volunteers from the government's Civil Protection office have been dispatched across Haiti, to warn people about flood and landslide risks, and about 1,250 shelters -schools, churches or other community buildings - have opened their doors to house people seeking refuge from the storm.