Subtropical Storm Fay formed in the Atlantic on Friday as forecasters issued a tropical storm watch for Bermuda.

The U.S. National Hurricane Center in Miami said the storm was 525 miles (845 kilometers) south of Bermuda on Friday afternoon. The storm was moving north-northwest at 12 mph (19 kph), with maximum sustained winds of 40 mph (64 kph).

Fay was expected to strengthen over the weekend and to produce rainfall of 2 to 4 inches in Bermuda as well as generate large swells along the island's southern coast.

Forecasters said Fay likely would turn toward the north and increase in speed Saturday, then turn toward the northeast Sunday, staying well out in the Atlantic.

Bermuda's government weather service said the storm was expected to pass southeast of Bermuda early Sunday.