Tropical Storm Erin may near Puerto Rico and the Dominican Republic before likely turning north as a hurricane, sparing the U.S.

Tropical Storm Erin officially formed in the eastern Atlantic on Monday morning, just west of the Cabo Verde islands. This system is expected to continue moving west to west-northwest at 15 to 20 mph across the eastern and central tropical Atlantic.

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,