Washington - Pacific storm Rick reached hurricane strength on Friday and was forecast to become a powerful category four storm by early next week, the US national weather service said.

The hurricane was churning off Mexico's southern coast Friday, with maximum sustained winds nearing 75 miles (120 kilometers) per hour.

At 8:00am Pacific time (1500 GMT) Rick's center was about 290 miles (470 kilometers) south of Acapulco, Mexico.

Outer bands of the storm were expected to lash the Mexican coast with rain later Friday.

It was moving west at a rate of nine miles (15 kilometer) per hour.

Rick was predicted to head on a north-westward trajectory, approaching the southern tip of Mexico's already storm-battered Baja Peninsula by Wednesday.

It is the seventh hurricane of the eastern north Pacific 2009 season and comes on the heels of Tropical Storm Patricia, which last week placed Los Cabos on Baja's southern tip under a state of emergency, before petering out.

The peninsula was battered in early September by Jimena, which ripped the roofs off houses and caused floods that killed at least one person.