Santo Domingo.- Tropical Storm Isaac strengthened slightly as it swirled toward the Dominican Republic and Haiti, but seemed unlikely to gain enough steam early Friday to strike the island of Hispaniola as a hurricane, AP reports.

It said the storm didn’t gain the kind of strength in the Caribbean that forecasters initially projected made, so it’s more likely that Isaac won't become a hurricane until it enters the Gulf of Mexico, said Eric Blake, a forecaster with U.S. National Hurricane Center in Miami.

The latest five-day forecast showed the storm's path shifting to the west, possibly making landfall in the north central shore of the Gulf of Mexico.

The storm dumped heavy rain Thursday across eastern and southern Puerto Rico and whipped up waves as high as 10 feet (3 meters) in the Caribbean as it churned across the region.

Early Friday, Isaac was centered about 165 miles (265 kilometers) south of the Dominican capital Santo Domingo, with maximum sustained winds of 45 mph (75 kph), moving west near 15 mph (24 kph), according to the hurricane center.