Powerful Hurricane Orlene headed Sunday toward Mexico's Pacific coast, where it is expected to make landfall on Monday night, the US National Hurricane Center said.
The storm lost some strength as it moved across the water, falling from Category 4 to 3, the agency said.
But it is expected to be a strong hurricane when it passes near or over the Islas Marias archipelago, and remain a hurricane when it reaches southwestern Mexico, the NHC said.
The NHC forecast that the storm would pass over the Islas Marias Sunday night or Monday morning, and reach the mainland by Monday night.
Mexico's National Water Commission (Conagua) predicted that the storm would be a Category 1 or 2 hurricane by the time it moves onto land.
PAY ATTENTION: Follow us on Instagram - get the most important news directly in your favourite app!
The storm will generate wind gusts of up to 70 miles (110 kilometers) per hour and waves of up to 16 feet (five meters) on the coasts of Nayarit and Jalisco states, Conagua added, urging the inhabitants of at-risk areas to take refuge in temporary shelters.
The Ministry of the Navy has closed the ports of Nayarit and Jalisco.
Authorities are keeping a close eye on the storm's track as they mull whether to evacuate tourists from Mexican beach resorts to temporary shelters, Víctor Hugo Roldan, director of Civil Protection in Jalisco, told the press.
Tropical cyclones hit Mexico every year on both its Pacific and Atlantic coasts, usually between May and November.
In October 1997, Hurricane Paulina hit Mexico's Pacific coast as a Category 4 storm, leaving more than 200 dead.