Hurricane Guillermo formed in the Pacific Ocean Friday but could weaken by the weekend, said forecasters.

Guillermo's maximum sustained winds reached near 130 km/h with little further strengthening expected, the U.S. National Hurricane Center in Miami said.

Forecasters say it could weaken when it passes over cooler waters on the weekend.

Late Friday, the storm was located 1,900 kilometres west-southwest of the southern tip of Mexico's Baja California peninsula.

It's moving west around 24 km/h.