Hurricane Erin weakened slightly Saturday night but is still a formidable Category 4 storm north of Puerto Rico. The 11 pm advisory from the National Hurricane Center now has Erin with winds of 140 mph,

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.

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.