Tropical Storm Erin is forecast to rapidly strengthen into a hurricane this weekend as it nears the northeastern Caribbean and Bahamas, raising concerns for strong winds, heavy rain, and dangerous surf along the islands.

Tropical Storm Erin formed in the eastern Atlantic Ocean on Monday, forecasters said. The storm could strengthen to become the Atlantic's first hurricane of the season.

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.