Hurricane Erin has weakened slightly to a Category 4 storm while positioned northeast of Puerto Rico and is on course to brush along the U.S. East Coast.

Hurricane Erin exploded in strength to a Category 5 storm in Atlantic waters just north of the Caribbean on Saturday, rapidly powering up from a tropical storm in a single day, the National Hurricane Center said.

While a Gulf disturbance that moved into Texas on Friday seems to have run its course, Hurricane Erin in the western Atlantic intensifies.