Tropical Storm Leslie strengthened in the Atlantic late Monday, Sept 3, but was barely moving over open ocean on a track that could take it closer to Bermuda by Saturday, AP reports.

With its 65-mph winds, the storm was causing potentially dangerous surf in parts of the Leeward Islands, Puerto Rico and the Virgin Islands.

The storm was centered about 585 miles south of Bermuda, according to the National Hurricane Center. It was expected to continue to move very slowly while possibly strengthening further over the next couple of days.

In the eastern Pacific, meanwhile, Tropical Storm John weakened to a depression hours after forming Monday near the Mexican island of Socorro, far from the mainland. John had maximum sustained winds of 35 mph and was forecast to weaken further Wednesday.

Also Monday, the 13th tropical depression of the Atlantic hurricane season formed far out in the ocean and posed no immediate threat to land.

The depression was located 1,390 miles northwest of the Cape Verde Islands late Monday and had maximum sustained winds of 35 mph, the National Hurricane Center in Miami said. It was creeping northwestward at 5 mph and was expected to continue in a northwesterly direction.

The depression could strengthen into a tropical storm by Tuesday. A weather disturbance is considered a tropical storm when its winds have strengthened to between 39 mph to 73 mph. Storms become hurricanes when their winds reach a minimum of 74 mph.