Tropical Storm Tomas has been hammering islands in the eastern Caribbean, knocking out power and damaging homes.
The storm has been blamed for two deaths and several injuries.
Tomas was located early Monday about 135 miles northeast of Curacao and was moving west at 14 miles per hour. The storm's winds had decreased to near 50 mph.
Tomas was briefly a hurricane before losing power, and forecasters say it could return to hurricane strength. The U.S. National Hurricane Center in Miami predicted more weakening before it begins to strengthen again around midweek.
The storm could threaten the island nation of Haiti, where more than a million earthquake victims are still living in crowded refugee camps and are very vulnerable to wind and rain. With no shelters or organized evacuation plans - and for most people, nowhere to go - Haitians will largely be on their own.
Daniel Brown, a center forecaster, said Tomas is "likely to strengthen when it's over the central Caribbean," and Haiti could be hit by rains from outer bands in another couple of days.
Brown said it was too early to say how strong Tomas could become later in the week or if Haiti might suffer a direct hit. But, he added, "there's certainly going to be the threat of heavy rainfall" in the impoverished nation, where widespread deforestation and ramshackle homes mean even moderate rains can cause devastation.
Aid workers in Haiti fear the worst. Hundreds of thousands of people there have only rudimentary shelter nearly 10 months after the Jan. 12 earthquake, and a cholera epidemic has killed more than 330 and hospitalized nearly 5,000.