Heavy rains were forecast to start late Friday in Antigua and Barbuda, the U.S. and British Virgin Islands and southern and eastern Puerto Rico.

Erin became a Category 1 hurricane with maximum sustained winds of 75 mph, the center said at 11 a.m. EDT. A tropical storm watch is in effect for Anguilla and Barbuda, Sint Maarten, St. Martin and St. Barthelemy and Saba and St. Eustatius in the Caribbean.

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.