MIAMI — Hurricane Rick quickly strengthened into an "extremely dangerous" Category 4 storm early today off Mexico's Pacific coast with winds near 135 mph, the U.S. National Hurricane Center said.

Rick was centered at 6:15 a.m. today about 255 miles southwest of Acapulco, Mexico.

"It's a bad storm. It's a strong Category 4 hurricane at this time," meteorologist Jessica Schauer told The Associated Press, adding it could become a Category 5 hurricane later in the day.

She said the storm was now "extremely dangerous" after warm waters fueled its rapid jump from a Category 1 hurricane to a strong Category 4 hurricane in only about 36 hours.

Schauer said Rick was moving parallel to southwestern Mexico's coast and more strengthening was expected in the next 36 hours. "Right now it's over very warm water and the current forecast track keeps it over warm water for quite a while," she said.