Hurricane Erin is forecast to continue growing in size, with hurricane-force winds extending up to 50 miles from its center.

Hurricane Erin weakened to a Category 3 storm with maximum sustained winds of 125 mph as its outer bands pounded the Virgin Islands and Puerto Rico with gusty winds and heavy rains Sunday. The U.S. East Coast is forecast to have rough ocean conditions through the middle of the week as the storm strengthens,

The storm is about 150 miles north of San Juan, Puerto Rico. Erin rapidly intensified into a category 5 major hurricane late Saturday morning. Erin is one of the fastest-growing storms on record. Its sustained winds increased from 75 mph on Friday morning to l60 mph by Saturday morning.

Erin, the first hurricane of the season, exploded to a Category 5 hurricane Saturday, and despite fluctuations in intensity, the storm is remaining formidable this weekend. Here's where it could head in the week ahead.

A westward-moving tropical wave could produce an area of low pressure in the tropical Atlantic late in the week of Aug. 18, the hurricane center said on Aug. 16. The center shows a 20% chance of storm formation over the next week.