Erin has strengthened into a hurricane as it approaches Puerto Rico and the Virgin Islands, bringing heavy rains that could cause flooding and landslides.

Hurricane Erin was expected to soak the Virgin Islands and Puerto Rico with heavy rain through the weekend before heading north up the Atlantic.

Heavy rains are forecast to start with the storm expected to become a major Category 3 storm over the weekend.

Tropical Storm Erin is tracking quickly westward through the open Atlantic waters and should become increasingly organized in the coming days, potentially reaching major hurricane intensity this weekend as it tracks just north of the Caribbean islands, where it could bring rain and gusty winds.

Tropical Storm Erin -- which is forecast to strengthen into the first hurricane of the Atlantic season by Saturday morning -- won't have a direct impact on the U.S., but it will bring dangerous rip currents to the East Coast.