Hurricane Erin is now a Category 4 storm, rapidly intensifying overnight into early Saturday morning as it moves closer to the U.S. East Coast with sustained winds up to 155 mph.

Tropical Storm Erin is slightly intensifying and forecast to become a hurricane Friday with a chance of ultimately affecting the U.S. East Coast next week.

Tropical Storm Erin, now spinning far out in the central Atlantic Ocean, could undergo rapid intensification into a powerful 125-mph hurricane.