Category 3 Hurricane Willa is expected to make landfall late Tuesday on Mexico's west-central Pacific coach, the National Meteorological Service (SMN) said.
The storm, which has maximum sustained winds of 205km/h (125mph), is expected to come ashore somewhere between San Blas, Nayarit state, and Mazatlan, Sinaloa.
At 15:00 GMT, Wilma was located some 55km (35mi) west-southwest of Las Islas Marias, Nayarit, and 205km (130mi) south-southwest of Mazatlan, according to the US National Hurricane Center.
The hurricane was moving to the north-northeast at 9km/h (6mph).
The NHC 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.
On the other hand, Tropical Storm Vicente was downgraded to tropical depression and is nearing the shores of Michoacan.
The SNM indicated that Vicente is some 25km (15.5mi) southwest of Lazaro Cardenas, Michoacan and is moving north-northeast at 19km/h (12mph).
Flooding from rains associated with Vicente caused a freight train to derail in Michoacan.
The SNM forecast includes torrential rains in the Pacific states of Sinaloa, Nayarit and Jalisco, as well as intense storms in Durango, Michoacan and Colima.
The service also urged extreme caution, as the rains may cause "landslides, river overflows and damage to roads," as well as "flooding in low regions."