Hurricane Kay gathered strength in the Pacific Ocean on Wednesday and was on course to bring strong winds and heavy rain to Mexico's Baja California Peninsula, forecasters said.

The storm has become a Category Two hurricane -- the second lowest on a scale of five, according to the US National Hurricane Center (NHC).

At 1800 GMT, Kay packed maximum sustained winds of around 105 miles (170 kilometers) per hour and was located about 210 miles southwest of Baja California's southern tip, the NHC said.

Hurricane or tropical storm warnings were in effect for much of the peninsula's coastline, and there was a risk of flash flooding, landslides and destructive waves, it said.

Authorities opened storm shelters in the state of Baja California Sur, home to several beach resorts including Cabo San Lucas.

The center of Kay was expected to pass to the west of southern Baja California on Wednesday before moving north close to the peninsula's western coast,  the NHC said.

Heavy rain and large swells could also affect the US state of California in the coming days, it warned.

Mexico is regularly lashed by tropical storms on both its Pacific and Atlantic coasts, generally between the months of May and November.

This year was the first since 1997 that no tropical cyclones formed in the North Atlantic, Caribbean Sea or the Gulf of Mexico in August, according to the NHC.