PUERTO VALLARTA, Mexico -- Hurricane John lashed tourist resorts with heavy winds and rain Wednesday as the dangerous storm marched up Mexico's Pacific coast, and forecasters predicted its center would brush close to land before nicking the tip of Baja California and heading out to sea.

The Category 4 hurricane could dump up to a foot of rain along parts of Mexico's southern coast, causing landslides or flooding, meteorologists warned. The hurricane had maximum sustained winds of 135 mph and stronger gusts capable of ripping roofs off buildings and causing storm surges of up to 18 feet above normal. It was expected to strengthen somewhat throughout the night Wednesday.

John was not expected to affect the United States -- cooler Pacific waters tend to diminish the storms before they reach California. But a hurricane warning covered a more than 300-mile stretch of the Mexican coastline from the port city of Lazaro Cardenas north to Cabo Corrientes, the southwestern tip of the bay that holds Puerto Vallarta.

The government also issued a hurricane watch for portions of the southern Baja Peninsula, from La Paz south on the east coast and from Sante Fe south on the west coast, an area which includes the resort city of Cabo San Lucas.

So far, the most damaging winds have remained offshore, and only tropical storm-force winds have hit the coast.

Skies were clear and tourists relaxed on the beach in Puerto Vallarta. But officials postponed the arrival of a Carnival cruise chip and prohibited customary tours of the bay.

Aniko Simon, 37, a tourist from Toronto, gathered with her family on the beach. She said she hadn't been aware there was a hurricane in the area until last night, when she saw a television news report. The family plans to return home Friday as scheduled.

William Rousseau, a tourist from Oregon vacationing with his family in Puerto Vallarta, said hotel officials warned about the hurricane "but we're calm because they say it's not going to hit this city."

"We're continuing to enjoy the city," he said. "They just asked us not to go into the ocean or on any bay tours."

Other tourists could be seen strolling through the streets visiting craft shops and eating in restaurants.

In Cabo San Lucas on the Baja Peninsula, there was more urgency, with fishermen and port authorities rushing to prepare for the hurricane, and local authorities setting up shelters.

"We are preparing shelters for the evacuation of civilians, if that becomes necessary," said Luis Armando Diaz, mayor of Los Cabos, situated on Baja's southern tip. "According to the information we have, the storm is coming right toward Los Cabos."

Cabo San Lucas Port Captain Everardo Jimenez said he instructed the operators of a tourist boat to get the craft out of the water.

Back on the mainland and closer to the storm's current location, the area south of Lazaro Cardenas to the resort of Acapulco was under a tropical storm warning. Tropical storm-force winds were lashing Lazaro Cardenas and the resort of Ixtapa-Zihuatanejo.

Although the center of John was forecast to remain just offshore, hurricane-force winds were likely to begin raking beaches near Puerto Vallarta late Wednesday, the National Hurricane Center in Miami said. The storm was then expected to nick Los Cabos at the tip of the Baja California Peninsula on Friday before heading out to sea.

The Mexican army and emergency services were on alert all along the coast. The civil protection agency for the state of Jalisco, which includes Puerto Vallarta, announced it would ask 8,000 residents living in risk-prone coastal areas to evacuate voluntarily to 900 temporary shelters. Those who refused would be moved by police officers, the government agency Notimex reported.

Mexican forecasters predicted up to 10 inches of rain on the coast and "torrential downpours" in the Jalisco state capital of Guadalajara, Notimex said. Public schools were canceled in Acapulco and surrounding communities.

In the resort cities of Ixtapa and Zijuatanejo, about three hours up the coast from Acapulco, authorities closed the port to small ocean craft and set up temporary shelters. Some students decided to leave school early before any potential flooding.

Light rain fell in Ixtapa, where the five-star Emporio Hotel received only minor warnings of rising tides. Receptionist David Gonzalez said none of the hotel's 92 guests had said they would leave early.

Pedro Ochoa, reception clerk at the four-star Posada Real Ixtapa Hotel, said neither staff nor guests were making any special preparations for the storm because "we were advised that it was headed elsewhere."

The center of the hurricane Wednesday night was about 100 miles south of Manzanillo and its outer bands, packing heavy rain, were churning toward the resort and port city, according to the hurricane center. John was moving to the northwest near 16 mph. So far, the most damaging winds have remained offshore, and only tropical storm-force winds have hit the coast.