Tropical Storm Erin formed on Monday and is expected to become a hurricane, and possibly a major hurricane, later this week.

Tropical cyclones become tropical storms when sustained winds reach 39–73 mph, are upgraded to hurricanes at 74 mph, and become “major” hurricanes at 111 mph or higher, corresponding to Category 3–5 on the Saffir-Simpson Hurricane Wind Scale.

Tropical Storm Erin formed in the far eastern Atlantic Monday and is expected to become the first major hurricane of the 2025 Atlantic hurricane season.