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

Erin, the first hurricane of the season, is now forecast to become a Category 4 by Sunday. Here's where it could head in the week ahead.

Hurricane Erin is rapidly intensifying as it tracks above the northeastern Caribbean Saturday, churning up rough surf and sending rain and gusty winds to islands south of its path.