Hurricane Erin exploded in strength to a Category 5 storm in the Caribbean before weakening on Saturday, the National Hurricane Center said.

Additional strengthening is expected as the storm is forecast to “remain a large and dangerous major hurricane through the middle of this week,” the National Hurricane Center said.

Hurricane Erin has been downgraded to a Category 3 hurricane. Hurricane Erin was downgraded to a Category 3 hurricane early Sunday as a tropical storm warning was issued for the Turks and Caicos Islands and winds and heavy rains whipped the Virgin Islands and Puerto Rico.

Much of North Carolina’s Outer Banks region is under a tropical storm watch with Hurricane Erin expected to skirt the area Wednesday through Thursday, according to the National Hurricane Center.

Erin, moving near the Leeward Islands, strengthened into a hurricane on Friday morning and is expected to pass north of Puerto Rico this weekend, the National Hurricane Center said.

Hurricane Erin became the first hurricane of the season Friday morning, and is expected to develop into a major Category 3 storm this weekend then intensify further as it passes to the north of Puerto Rico in the Atlantic,