Farther south, meanwhile, Mexican officials reported that there had been 12 deaths related to heavy rains from Tropical Storm Vicente.
Mexico City: Authorities rushed to evacuate low-lying areas and set up shelters as an "extremely dangerous" Hurricane Willa with winds of 145 mph (230 kph) headed toward a Tuesday afternoon landfall along a stretch of Mexico's Pacific coast dotted with high-rise resorts, surfing beaches and fishing villages.
Farther south, meanwhile, Mexican officials reported late Monday that there had been 12 deaths related to heavy rains from Tropical Storm Vicente.
Willa briefly reached Category 5 strength, then weakened a bit to Category 4. But the US National Hurricane Centre warned that it still was likely to bring "life-threatening storm surge, wind and rainfall" to parts of west-central and southwestern Mexico.
Workers taped up windows in hotels and officials ordered schools closed in a low-lying region where towns sit amid farmland tucked between the sea and lagoons. A decree of "extraordinary emergency" was issued for 19 municipalities in Nayarit and Sinaloa states, the federal Interior Department announced.
Officials said 7,000 to 8,000 people were being evacuated from low-lying areas, mostly in Sinaloa state.
The hurricane was expected to first pass over or near the Islas Marias, a group of islands about 60 miles (96 kilometres) offshore that include a nature preserve and a federal prison. Forecasters said Willa would then blow ashore in late afternoon somewhere along a 140-mile (220-kilometre) stretch from the resort city of Mazatlan to San Blas.
Enrique Moreno, mayor of Escuinapa, a municipality of about 60,000 people lying on Willa's potential track, said officials were trying to evacuate everybody in the seaside village of Teacapan. He estimated 3,000 were affected but he expected some would try to stay.
"The people don't want to evacuate, but it's for their security," he said.
About 60 miles (100 kilometres) up the coast in Mazatlan, with a metropolitan-area population of about 500,000, Mayor Jose Joel Boucieguez said officials prepared shelters and were closely monitoring low-lying areas. Mazatlan is a popular vacation spot and home to a large number of American and Canadian expatriates.
Late Monday, Willa was centred about 85 miles (140 kilometres) southwest of the Islas Marias and 195 miles (310 kilometres) south-southwest of Mazatlan. It was moving north at 9 mph (15 kph), but was forecast to make a turn to the northeast during the night.
Hurricane-force winds extended 35 miles (55 kilometres) from the storm's core, and tropical storm-force winds were up to 125 miles (205 kilometres) out.
The US hurricane centre warned that Willa could bring 6 to 12 inches (15 to 30 centimetres) of rain — with up to 18 inches (45 centimetres) in some places — to parts of Jalisco, Nayarit and Sinaloa states, with flash flooding and landslides possible in mountainous areas.
Farther to the south, a weakening Tropical Storm Vicente was expected to dissipate soon, but it still caused heavy rainfall that caused dangerous flooding in southern and southwestern Mexico.
Officials in Oaxaca state said seven adults and five children had lost their lives in drownings or mudslides.