HILO, Hawaii (AP) — The Latest on tropical weather systems threatening Hawaii (all times local):

5:30 p.m.

A hurricane watch is being expanded in Hawaii as a powerful storm churns across the Pacific Ocean.

The National Weather Service says that now Oahu is under the watch due to Hurricane Lester. The watch was already in effect for the Big Island and Maui County.

The Hawaii areas are bracing for possible impacts from Lester, which strengthened to a major Category 3 storm.

Maui County Emergency Management Officer Anna Foust said Thursday the island is small enough and the storm big enough that the whole island could be impacted.

Forecasters say Lester is on a track to pass just north of the island chain over the weekend.

Its approach follows on the heels of Hurricane Madeline, which was downgraded to a tropical storm as it brushed by the islands without causing major damage.

4:15 p.m.

Maui County officials are bracing for possible impacts from Hurricane Lester, which has strengthened to a major Category 3 storm.

Maui County Emergency Management Officer Anna Foust said Thursday the island is small enough and the storm big enough that the whole island could be impacted.

Foust says she’s concerned residents may not take Hurricane Lester seriously after Madeline passed without incident.

Some business managers in the north shore town of Paia say they haven’t done anything to prepare.

Schools, courts and government offices are closing at noon Friday to give people time to prepare for the storm.

Maui County workers are deploying generators, topping out fuel and planning to open emergency shelters.

Lester is expected to gradually weaken but remain a hurricane as it passes the islands this weekend.

___

2:20 p.m.

Hurricane Lester has strengthened to a major Category 3 storm as it reels toward Hawaii.

The storm has maximum sustained winds of 120 miles per hour and was 640 miles East of Hilo Thursday afternoon.

Meteorologist Eric Lau says the storm is expected to gradually weaken over the next two days. But he says it’s likely to remain a hurricane as it passes the islands over the weekend.

Hawaii County and Maui County, which includes Maui, Lanai, Molokai and Kahoolawe, are under a hurricane watch.

Hawaii Volcanoes National Park opened some areas Thursday as Hurricane Madeline passed. But the campgrounds and coastal lava viewing remain closed as Lester approaches.

___

12 p.m.

The U.S. Coast Guard is opening ports in Hawaii County, and cargo operations are resuming.

Ports are opening Thursday so ships can deliver goods and services to the Big Island before the possible arrival of Hurricane Lester.

The Coast Guard urges boaters to exercise extreme caution while Lester approaches the islands over the weekend. They are saying mariners should secure their boats and equipment or move large boats to protected marinas.

They are also urging visitors to Hawaii to heed warnings from lifeguards and officials.

___

11:10 a.m.

The state Department of Education says schools on the Big Island will re-open Friday.

Schools had been closed Wednesday and Thursday as Tropical Storm Madeline brushed by the state.

Superintendent Kathryn Matayoshi said Thursday that there were no reports of damages to schools. She says the department will remain vigilant as Hurricane Lester makes its way to the islands.

Lester was about 680 miles east of Hilo on Thursday morning with maximum sustained winds of 110 mph. Meteorologist Ian Morrison says the Category 2 storm strengthened slightly Thursday morning, but it was expected to weaken. He says Lester could begin affecting the islands Friday night.

___

9:20 a.m.

Maui County and Hawaii County are under hurricane watch as Category 2 Lester careens toward the islands.

The storm is on a track to pass just north of the island chain and the eye of the storm isn’t expected to make landfall. But meteorologist Ian Morrison from the National Weather Service says if the storm veers to the south, it could have a much greater impact.

Lester is expected to slowly weaken and remain a hurricane as it blows by the state. After it passes it’s expected to further weaken to a tropical storm.

Morrison says the eastern part of the state could be hit with heavy rains and tropical storm or hurricane-force winds starting Friday night. He says all islands could be impacted as the storm passes.

___

6:30 a.m.

A tropical storm warning for Madeline in Hawaii has been canceled.

The storm has moved to the south of Hawaii’s Big Island. However, the islands will feel the effects of strong winds.

The National Weather Service in Honolulu has issued a wind advisory.

Winds of 25 to 35 mph, with gusts to 50 mph, could occur across the island chain. The winds will bring the potential of blowing objects, power outages and downed tree branches.

Madeline was downgraded Wednesday though it brought periods of intense rainfall.

Meanwhile, Hurricane Lester continues to track toward Hawaii. A hurricane watch has been issued for Hawaii County.