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 early Sunday.

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

Despite this, the US National Hurricane Center (NHC) says Erin is growing in size, with tropical-storm-strength winds extending 205 miles from its centre. Storm-related hazards, including flash flooding and landslides, are expected in the Virgin Islands and Puerto Rico.

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.