Tropical Storm Dorian tracking north of Puerto Rico

Tropical Storm Dorian, the fourth cyclone of the Atlantic hurricane season, is moving through the Atlantic, tracking to pass north of Puerto Rico by early next week.

The storm was becoming more organized early Thursday, with maximum sustained winds of 60 mph about 700 miles west of the Cape Verde Islands, according to the National Hurricane Center.

From there, there is some uncertainty as to how the storm could develop. Dorian is expected to move relatively quickly toward the west or west-northwest, passing north of most of the Caribbean islands. Forecasters are calling for it to remain a tropical storm through Tuesday, though said they had low confidence in that because of a mix of factors that could enhance or inhibit intensification.

The storm is ahead of schedule as far as a normal hurricane season goes. The fourth named system typically doesn't arrive until Aug. 23, according to the hurricane center. To qualify as a named storm, a cyclone must have maximum wind speeds of at least 39 mph and tropical characteristics.