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.

Hurricane Erin rapidly strengthened into a Category 5 storm. It is not expected to make a direct hit on the U.S. but will create dangerous surf.

Tropical Storm Erin is brewing in the Atlantic as we enter the peak of the Atlantic hurricane season. The storm is expected to become the first major hurricane of the 2025 season. But, what makes a tropical storm become a hurricane,