Tropical Storm Erin sputtered in the open waters of the eastern Atlantic when it was wrapped in a veil of dry, dusty air from the Sahara, which limited the storm’s ability to strengthen. But it’s still set to become a hurricane by the weekend,

Tropical Storm Erin is expected to strengthen into a hurricane later this week in the Atlantic Ocean, according to the National Hurricane Center.

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