Hurricane Willa intensified to a Category 5 on Monday as it continued its approach to Mexico's Pacific coast, the country's National Weather System (SMN) said.
The storm, which has maximum sustained winds of 260km/h (160mph), is expected to make landfall late Tuesday somewhere between San Blas, Nayarit state, and Mazatlan, Sinaloa.
In its latest bulletin, the SMN said that Willa is some 215km (135mi) southwest of Cabo Corrientes, Jalisco, and 280km (175mi) south-southwest of Las Islas Marias, Nayarit.
Willa is moving north at 11km/h (7mph).
The US National Hurricane Center has issued a hurricane warning for San Blas to Mazatlan, including Las Islas Marias.
A tropical storm warning is in effect for Playa Perula to San Blas, and from Mazatlan northward to Bahia Tempehuaya.
According to the SMN forecast, Willa is expected to change its track toward the northeast early Tuesday and will hit the coast in the afternoon, causing very strong storms and intense rains in Jalisco and Colima, as well as Baja California Sur, Sinaloa, Nayarit and Durango.
Wilma, a "potentially catastrophic" hurricane, will be accompanied by a dangerous storm surge, the NHC said.