The outer bands of Tropical Storm Rafael drenched the Caribbean's Northern Leeward Islands as its centre steadily moved on a possible track towards Bermuda.
There were no immediate reports of any significant damage or injuries in the Caribbean islands as the centre of the tropical storm churned north-northwest at about 10mph. Late on Sunday, it was moving north-northeast of San Juan, Puerto Rico, and was packing winds of about 60mph.
Forecasters at the US National Hurricane Centre in Miami said Rafael could strengthen into a hurricane as it spins over the Atlantic.
Rafael could then approach the wealthy British Atlantic territory of Bermuda on Monday. The Bermuda Weather Service issued a tropical storm watch for the territory of about 70,000 people.
In the US Virgin Islands, Elton Lewis, the territory's emergency management director, said authorities "don't anticipate any significant impact" from the passing storm. There were off-and-on showers during much of the day.
Tropical storm warnings have been ended for Caribbean islands, but the possibility of flooding and mudslides are still a concern in some islands, particularly in mountainous terrain, since Rafael has been forecast to dump between 4in and 8in of rain over the Lesser Antilles, small islands that include Dominica, Martinique and St Lucia.
Rain ranging from 1in to 3in is expected in the US Virgin Islands and the outlying Puerto Rican islands of Culebra and Vieques.
Swells generated by Rafael are expected to hit eastern-facing beaches of the Bahamas during the next few days, but forecasters said the storm's centre will remain well east of the sprawling archipelago.