Hurricane Erin weakened to a Category 3 hurricane Sunday, its outer bands lashing the Virgin Islands and Puerto Rico, as forecasters warned the storm was rapidly growing in size and would gain new strength.

Erin became one of the earliest Category 5 hurricanes on record on Saturday. The storm will lash parts of the northern Caribbean on Sunday and Monday.

Erin is the first hurricane to develop over the Atlantic this year, and meteorologists are closely tracking its path and forecast.