Authorities are encouraging residents to remain vigilant about preparing as the busiest hurricane season in at least a decade reaches its midway point Monday.

“We’re going to be really lucky if we avoid the major impacts of these storms (hurricanes Ignacio and Jimena),” said Mayor Kirk Caldwell at a news conference Sunday in the city’s Emergency Operations Center. “But at some point we are going to get a direct hit. We need to be ready.”

Caldwell said Jimena, which was coming up behind Ignacio, could begin affecting the islands toward the end of the week. The National Weather Service canceled a tropical storm watch for Maui County and Hawaii island Sunday as Ignacio tracked northwest.

Since the beginning of the hurricane season June 1, nine tropical cyclones have passed through the Central North Pacific. Jimena would be the 10th.

Jimena, moving at 16 mph, was east of the 140th meridian west Sunday, the dividing line between the Eastern North and Central North Pacific regions.

Earlier this year forecasters predicted the Central Pacific would see a busier-than-normal season because of El Nino conditions, with five to eight storms forming in the region.

So far, five storms have formed in the Central Pacific region, which covers Hawaii. The other four storms developed in the Eastern North Pacific and moved into Hawaii’s region. Hurricane season ends Nov. 30.

Eric Lau, a forecaster at the National Weather Service in Honolulu, said August and September are typically the busiest months for hurricanes, but destructive storms have formed late in the season, such as Hurricane Iwa, which devastated the western part of the state Nov. 23, 1982.

Lau said Central Pacific hurricane seasons have been pretty quiet after Hurricane Iniki on Sept. 11, 1992, but picked up last year with five, when Tropical Storm Iselle caused power outages and structural damage on Hawaii island.

Despite this season’s frenetic activity, only one storm, Kilo, brought any significant impact to the islands, Lau said.

Rain associated with Kilo caused some sewage spills on Oahu. Lau pointed out that Kilo didn’t cause the rain and only pushed moisture up from the south, allowing the rainy conditions to develop.

This season has also created a unique situation for forecasters in Hawaii: Weather maps Sunday morning showed three Category 4 hurricanes lined up across the Pacific: Kilo, Ignacio and Jimena. It was the first time forecasters saw three major hurricanes at the same time in the vicinity of Hawaii, Lau said.

At the mayor’s news conference, Caldwell and other city officials made several announcements:

» Public schools on Oahu are expected to be open Monday and Tuesday.

» City employees should report to work Monday and Tuesday.

» The Coast Guard is not planning to close any commercial ports.

» Watch out for flooding conditions and remove any possible flying debris from yards and lanai.

» Be responsible about recreational activities and avoid going out in dangerous conditions that could put rescuers in danger.

Melvin Kaku, director of the city’s Department of Emergency Management, urged residents to be prepared, remain flexible and stay informed because significant changes can happen in hours, and a storm can move outside of the cone of its projected path.

Caldwell said residents might get tired of preparing for storms that seem to have no impact, but it doesn’t take much effort to stay informed.

“Please don’t let your guard down, and be ready,” he said. “We survive through one of these things by protecting ourselves.”