On Bay Road in Basseterre, St. Kitts, two taxis were washed down to the shoreline when they tried to cross the flooded road.
- The tropical storm could become a hurricane on Monday
- Officials in Bermuda issue a tropical storm watch
- Hurricane center: Rainfall could cause "life-threatening flash floods and mudslides"
(CNN) -- Tropical Storm Rafael churned in the central Atlantic early Monday as it neared hurricane strength, forecasters said.
Maximum sustained winds increased to 70 mph late Sunday, according to the National Hurricane Center in Miami. The storm was centered about 290 miles (465 km) north-northeast of San Juan, Puerto Rico, and was swirling north-northwest at 10 mph.
"Some strengthening is forecast ... and Rafael is expected to become a hurricane later today," the hurricane center said.
A projection map shows Rafael headed toward Bermuda later this week.
College Street, which runs through the middle of Basseterre, St. Kitts, is filled with floodwaters.
Basseterre flooding has cut off the east side of the city from the west side.
Officials there issued a tropical storm watch Sunday and told residents that they expected the storm to affect the British territory on Tuesday. A tropical storm watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.
While the National Hurricane Center predicted Rafael will stay well to the east of the Bahamas through Monday night, it did warn of life-threatening surf conditions and rip currents on the eastward-facing beaches of the Bahamas over the next few days.
Forecasters expect Rafael to leave between 4 to 8 inches of rain over the northern Leeward Islands, with some pockets getting as much as 12 inches.
"These rains could cause life-threatening flash floods and mudslides, especially in areas of mountainous terrain," the hurricane center said.
Rainfall amounts of 1 to 3 inches are possible in the Virgin Islands, Culebra and Vieques, forecasters said.
Read more: Tropical Storm Leslie expected to pass east of Bermuda
CNN's Chandler Friedman contributed to this report.