Hurricane Erick formed on Saturday off Mexico's Pacific coast and it was expected to crawl along offshore, weaken and may bring tropical storm-force winds to the southern Baja peninsula by late Sunday.
The U.S. National Hurricane Center said Erick was located about 90 miles (145 km) south of Manzanillo, Mexico's top cargo shipping port, at 10 a.m. (1500 GMT) and was packing maximum sustained winds of 80 miles per hour (130 km per hour).
The storm was not expected to get much more powerful and it should begin to lose strength by Sunday, the hurricane center said.
Mexico has no major oil installations in the Pacific but the storm shuttered the shipping ports in Manzanillo and Lazaro Cardenas, the government said in a statement.
The NHC said Erick was expected to skirt the coast, but it was still close enough that a change in course could send its center over land.
The Mexican government extended a tropical storm watch to the southern Baja peninsula. Tropical storm warnings were in effect along the Pacific coast and from Zihuatanejo in Guerrero state to Cabo Corrientes in Jalisco state.
Erick could dump up to 8 inches (20 cm) of rain along the coast and cause flash floods, the center warned.