It quickly powered up from a tropical storm to a Category 5 in a single day, the National Hurricane Center said.

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

Weather experts on the Leeward Islands, including Puerto Rico, are keeping close watch as Erin lurches toward the Caribbean and is on track to become a major hurricane.