Forecasters say Tropical Storm Erin has formed in the eastern tropical Atlantic Ocean as Hurricane Henriette is strengthening in the Pacific Ocean.

Tropical Storm Erin formed Monday and is expected to become a major hurricane as it moves across the Atlantic Ocean, according to the National Hurricane Center, though the potential risks to the U.S. remain unclear.

Tropical Storm Erin formed Monday in the eastern tropical Atlantic Ocean, just west of the Cabo Verde Islands, as Hurricane Henriette strengthened in the Pacific Ocean well away from Hawaii, forecasters said.