Sergio, the 10th hurricane of the year in the eastern Pacific, had maximum sustained winds of 70 mph and was centered about 360 miles southeast of the port city of Manzanillo, the U.S. Hurricane Center in Miami said.
Sergio was moving north at about 3 mph and was expected to make a gradual turn toward the northwest away from land.
The hurricane, which became a Category 2 storm Wednesday with maximum high winds of 110 mph, was dumping rain on a long stretch of the Pacific coast.
Tropical storm-force winds extended outward up to 115 miles.
Tropical storms become hurricanes when wind speeds reach 74 mph.