El Nino may be back for winter

By Curtis Lum
Advertiser Staff Writer

Hawai'i could be in for a drier winter and late-season hurricanes thanks to possible El Nino conditions developing in the coming months, the National Weather Service said.

El Nino is caused by a disruption in the ocean and atmosphere of the central Pacific Ocean. Since June, climate scientists have been tracking the spread of warm water eastward across the central Pacific and expect to determine soon — perhaps by the end of the week — whether the trend is a real one.

El Nino conditions occur regularly and last for about 18 months, said lead forecaster Hans Rosendal at the National Weather Service in Hawai'i. He said the Islands faced "pretty intense ones in the early 1980s and 1990s.

"El Nino for Hawai'i usually means dry, unsettled weather in our winter time. So that will be quite a contrast to the past winter where it was quite wet," Rosendal said. "It'll be good tourist weather, but it'll also mean we won't have the rainfall to keep our islands green and wet. The water supply might suffer after a while."

Rosendal said hurricanes also tend to form south of the islands during El Nino years and do so later in the season, which runs from June 1 to Nov. 30.

Hurricanes 'Iwa in 1982 and 'Iniki in 1992 formed during an El Nino season. The latter particularly devastated Kaua'i and caused heavy damage on O'ahu.

But Rosendal said it's still too early to predict what effect an El Nino might have.

"I think there's only a 50-50 probability that it will come to pass and then they expect it to be a fairly mild one," he said. "So there are still a lot of uncertainties involved."

The conditions typically occur once in four years. A weak El Nino in 2002-03 had no great effect on weather, but an El Nino of 1997-98 caused heavy rains in California and Florida.

Over the past 25 years, scientists developed tools to predict El Nino conditions with great accuracy, said research meteorologist Vernon Kousky of the National Weather Service in Camp Springs, Md.

"It's hard for one to sneak up on us now."

Reach Curtis Lum at 525-8025 or culum@honoluluadvertiser.com. USA Today contributed to this report.