Published: Oct 07, 2010 3:55 PM EDT
Updated: Oct 07, 2010 12:55 PM EDT

MIAMI (AP) - Otto, which had been a subtropical storm, has transitioned to a tropical storm as it meanders over the Atlantic and could reach hurricane strength.

The National Hurricane Center says Tropical Storm Otto has maximum sustained winds Thursday near 60 mph (95 kph). The storm could become a hurricane by Friday night or Saturday.

Otto is located about 255 miles (410 kilometers) northeast of Grand Turk Island and is drifting northeast near 2 mph (4 kph).

Subtropical storms share the characteristics of tropical storms, which get their power from the warm ocean, and extratropical storms that form when warm and cold fronts collide.