Strong, southwesterly winds buffeted O'ahu Thursday, as forecasters warned residents to get ready for even stronger winds through Friday afternoon, with gusts upwards of 60 mph expected in parts of Windward O'ahu.

The threat of damaging winds prompted the closure of public schools statewide Friday except for those on the Big Island, along with all O'ahu charter schools, the University of Hawai'i at Manoa and a number of private schools. Some charter schools on Kaua'i and the Big Island also canceled classes.

Nonessential state and city employees were given Friday off due to the threat of bad weather.

Meanwhile, some 76 homeless people sought refuge from the winds at temporary shelters, set up at Wai'anae, Kane'ohe, Waimanalo and Waialua district parks, the Red Cross said. The number of people at the shelters was expected to grow overnight, as the winds started to pick up and cause problems.

Some four dozen people went to the shelter at Wai'anae District Park.

City emergency management officials said residents should be prepared for powerful, potentially damaging gusts in some spots of the island, especially at high elevations and areas below north and east slopes.

"We're operating under the assumption that this is going to be a pretty bad storm," said John Cummings, spokesman for the city Department of Emergency Management.

A high-wind warning remains in effect for O'ahu through 6 p.m. Friday, and National Weather Service forecasters said the strongest winds will likely be felt overnight and Friday morning. The gusty winds are expected to die down considerably on O'ahu Friday night, probably just after dusk.

Forecasters predict a return to gentle tradewinds by Friday.

Robert Ballard, science and operations officer for the National Weather Service-Honolulu, said Windward O'ahu will likely get hit with the brunt of the winds. He urged residents to stay off the roads and remain indoors if possible because of the danger of flying debris.

"We really want people to be safe and cautious," he said. "It's going to be a wind event that is probably going to cause some problems."

O'ahu saw gusts upwards of 35 mph Thursday, with occasional 45 mph to 50 mph gusts. The blustery weather caused little damage, but a few headaches. Throughout the day, several outages were reported. And the high winds and choppy seas forced TheBoat to cancel all its voyages.

TheBoat will also not operate Friday morning.

Through about 5 p.m., firefighters responded to four calls for damaged roofs, all in Kane'ohe, Honolulu Fire Department spokesman Capt. Terry Seelig said. He said the department was preparing for emergency calls to increase overnight, and so had extra staff on duty.

There were also several small power outages yesterday, which were likely wind-related. Three of the outages were in Kane'ohe, knocking out power to more than 8,100 customers, including Windward Community College. Without power, Windward administrators canceled classes.

There was also an outage on Wilhelmina Rise that cut power to more than 1,300 customers.

Hawaiian Electric Co. spokesman Darren Pai said HECO crews were stationed around O'ahu to respond quickly in the event of more outages. He said extra crews would also be on call Friday.

Ballard, of NWS, said the strong southwesterly winds are being caused by a cold front making its way over the island chain. Thursday afternoon, the front was about 200 miles north of Honolulu. The winds are most dangerous in front of the storm, which will likely not bring any heavy downpours.

Before the worst winds were scheduled to hit Thursday, Windward residents started tying down loose objects around their homes and stocking up on emergency supplies. Some reported strong gusts racing through neighborhoods, snapping branches and downing at least one tree in Maunawili Valley.

"Anything that's less than 200 pounds has the ability to go flying," said Rob Mathews, the owner and operator of a sail and snorkel charter boat company at Heeia Kea Small Boat Harbor, who was tying down whatever he could. He said a recent storm, with lighter winds than those expected now, blew off sail covers and shade canopies from his 35-foot sailboat. For this wind storm, he said, "I've doubled up all the lines; that gets the boat further away from the dock so she had room to buck around."

In addition to strong winds, emergency officials were watching the big surf, which threatened to get bigger with the wind. The state closed the Yokohama Bay section of Ka'ena Point State Park because high, wind-whipped waves were creating hazardous conditions.

The state also canceled all camping permits for Peacock Flats and hiking permits for Kuaokala Forest Reserve. In a news release, DLNR chairwoman Laura Thielen urged people to stay off hiking trails and other outdoor areas. "High wind may cause trees to fall or other debris to be blown," she said.

Lifeguards also closed beaches on the North Shore.

Stephaney Bell, 52, of Los Angeles, said she came to see the big waves and was not disappointed.

"It's just overwhelming and very beautiful," Bell said.

Advertiser Staff Writer Will Hoover contributed to this report.