El Niño's end likely to bring normal rain

By Jan TenBruggencate
Advertiser Science Writer

El Niño is dying after running through the Pacific region for the past year, so rainfall in the Islands is expected to be fairly normal for the next few months — not too wet, not too dry.

With climate experts consistently forecasting the demise of El Niño, "the question now is whether it will move into a La Niña or stay normal," said University of Hawai'i oceanography professor Roger Lukas.

The El Niño-La Niña cycle is a complex Pacific-wide, and to some degree global, collection of climate events. El Niño, sometimes referred to as the "warm phase," can be associated with warmer-than-normal water in the equatorial Pacific, more tropical storms in the eastern Pacific and Hawaiian waters, and drier than normal winters in Hawai'i. La Niña, the "cold phase," has cooler-than-normal equatorial waters, but its effects on storms and rainfall are less clear.

"The forecast through October are near neutral," said Jim Weyman, meteorologist in charge at the National Weather Service's Honolulu forecast office and head of the Central Pacific Hurricane Center.

Kevin Kodama, hydrologist with the National Weather Service in Honolulu, said his estimate for Hawai'i rainfall this summer is that it will be about normal. Lukas said he figures rainfall to be normal, or slightly wetter than normal.

Part of the hesitancy is because forecasters find their existing models are not very efficient at predicting summer weather. They're much better at predicting rainfall in winter. Another issue is the number and strength of tropical storms likely to occur during the North Pacific's June-to-November hurricane season.

Weyman said he's making no predictions until the Weather Service's formal hurricane season press conference on May 19.

"We're still crunching numbers," he said. "We want to be sure as we get near to the season that we use the latest figures we have, and we want to include April and early May."