San Francisco Frontiers - Hurricane Simon strengthens to category 4 as it nears western Mexico

The US National Hurricane Center said Simon could strengthen further as it approaches west-central Mexico with winds of 150 miles (240 km) per hour.

"Preparations to protect life and property should be rushed to completion shortly in the hurricane warning area," the center said.

As Florida was assessing the damage caused by Isaias, the first hurricane of the Atlantic season, Mexico was bracing for Simon.

Simon is the latest in a busy hurricane season in the Pacific, where the powerful El Nino ocean warming phenomenon is weakening wind shear, allowing the storms to gain in strength.

In the Pacific tourist resort of Puerto Vallarta, the skies were cloudy on Saturday morning but the sea was still relatively calm.

Torrential rains caused by Simon have already caused flooding in Acapulco, another major tourist destination further south.

But residents of Puerto Vallarta, which sits on a huge horseshoe-shaped bay that helps defuse the power of a hurricane, appeared largely unfazed by the threat.

While shop owners sandbagged the entrances to their stores and boarded up the doors and windows, there was little sense of impending disaster.

"Simon says: 'Everything is going to be alright'", someone had spray-painted on a board, in a play on the name of a popular children's game.

Moises Villasenor, 72, said he was "a little worried" as he filled sand bags to protect his small hotel, situated about three blocks from the seafront.

But, on the whole, he said: "We're very positive."

Tourists also exuded calm.

"We're going to enjoy it as much as we can, even if it's just for today," said Edna Morales, 41, who arrived Friday from northern Mexico with her husband to celebrate their wedding anniversary.

Authorities said they would order residents to take shelter starting at 5:00 p.m. (2300 GMT).

Y.Gomez--SFF