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.

Heavy rains from Tropical Storm Erin killed seven people in Cabo Verde, and as it moves westward across the Atlantic, the system is now being closely watched by U.S. forecasters.

Tropical Storm Erin formed in the eastern tropical Atlantic on Monday morning and is forecast to grow into a major hurricane by the weekend, according to the National Hurricane Center. As of the NHC’s 2 p.