Islanders this winter can expect dry conditions, less rainfall, slightly lower temperatures and a greater chance of late-season tropical cyclones after mid-December — all thanks to El Niño.

Those were the conclusions of experts from the National Oceanic and Atmospheric Administration's Weather Service Wet Season and El Niño news conference yesterday. The purpose of the conference was to look at how El Niño will affect Hawaii during the upcoming wet season from now through April. It was also to alert the public to the possibility of storms.

"If you want to lessen the impact of a disaster, people must be prepared," said James Weyman, director of the Central Pacific Hurricane Center. "One of the things we're trying to do today is to let people know what might happen in the upcoming wet season."

Weyman said every two to seven years an El Niño occurs, causing Pacific Ocean surface temperatures to rise. That is what's happening now, he said. Sea surface temperatures are at least 1 degree higher than normal across much of the central and east central Pacific, he said.

"And that doesn't sound like a great deal, but when you get that expanse of ocean warmed up to that one or two degrees, it does cause a tremendous impact on weather patterns," Weyman said.

None of which holds much promise for the easing drought conditions that have plagued the Big Island, Maui and other parts of the state for the past several months.

"What happens with El Niño, you have more high- pressure systems, so you actually lose that trade-wind situation," Weyman said. "That's why you get less than normal precipitation."

Still, Kevin Kodama, senior service hydrologist for the Weather Forecast Office, offered a ray of hope to Hawaii's drought-stricken areas.

"One of the big El Niño impacts is dryer-than-normal rainfall conditions during our wet season (October through April)," said Kodama, who added that the dryness associated with El Niño is most pronounced from mid-December through April. Before that, light, steady rains can occur — the kinds of rains that saturate the ground and are beneficial to locations suffering from drought.

"So, what we're looking at right now is really a narrow window of opportunity for us to get any sort of drought relief for those areas that have existing drought conditions," Kodama said.

That window will close in about six weeks, he said.

"So we're looking at this month and into the early portion of December. And if we don't receive those normal seasonal rains, then we're not expecting a whole lot of relief for those folks — especially out on the Big Island — that currently have severe to extreme drought going on."

Kodama cautioned that parts of the state could get up to 50 percent less rain than usual during the dry season. There could mean wildfires, continued restrictions on water supplies and increased expenses for those living in the affected areas, he said.

Kodama and Weyman cautioned that even in dry periods, flash floods can occur when heavy rainfall hits an area in a short time.

"We're just trying to make people aware of what's possible:late-season hurricanes, or very strong hurricanes, the chance of drought once we get past December, and also the chance of flash floods," Weyman said.