A warm-water mass churning across the tropical Pacific points to the development of a periodic phenomenon that typically brings destructive weather across far reaches of the planet, two University of Hawaii scientists warn.

"I think the system is really primed for a big El Nino," says Axel Timmermann, a professor of oceanography with the International Pacific Research Center. "I would say there is an 80 percent chance that a big El Nino will develop by the end of the year."

Just how powerful the phenomenon will be is the subject of intense debate within scientific circles, Timmermann said in a telephone interview.

"The big discussion is if it will develop into a strong El Nino," he said. "You will find members of the scientific community who are more conservative in their estimates and less conservative."

But he said it’s his opinion that the El Nino will rival the one that occurred in 1997-98, the largest event of its kind in recorded history.

What is worrying scientists are abnormally warm subsurface conditions in a region called Nino 3, southwest of Hawaii.

"It’s an enormous amount of heat," Timmermann said.

By one estimate, published in the online magazine Slate, the heated water would cover the United States to a depth of 300 feet.

The temperature anomaly is accompanied by strong westerly winds.

When the water mass reaches the surface, which it could later this year, the heat would be released into the atmosphere, creating the potential for "devastating impacts," Timmermann said.

More conservative in its prediction is the National Weather Service’s Climate Prediction Center, based in College Park, Md.

In a report issued Thursday, it said the chances of an El Nino developing will top 50-50 by summer.

Many computer models are predicting an El Nino sometime during the summer or fall, the center said.

"Despite this greater model consensus, there remains considerable uncertainty as to when El Nino will develop and how strong it may become."

In agreement with Timmermann is Fei-Fei Jin, a UH professor of meteorology.

"The subsurface heat content is very, very substantial," he said Thursday. "Most people are still cautious, but we have a bunch of experts here on the campus who have been very watchful of this for over a month and we are thinking it could be a pretty serious one."

In Hawaii the results could mean a dry winter and wet summer, forecasters say.

"Every El Nino is a little bit different," said Robert Ballard, science and operations officer with the National Weather Service in Honolulu. "But there are some patterns we can expect to see. For Hawaii what we tend to see is the weather pattern during the summer and fall becomes favorable for more tropical cyclones to develop in the central Pacific. That does not mean that more tropical cyclones will threaten Hawaii. There is no way to know that."

Hurricanes Iwa in 1982 and Iniki in 1992 occurred during El Nino years.

And the 1997 Pacific hurricane season was one of the deadliest and most destructive, although Hawaii was spared.

Hurricane Pauline killed several hundred people and caused widespread damage in southeastern Mexico. Hurricanes Linda and Guillermo reached Category 5 strength but fortunately never made landfall.

If an El Nino develops, it would likely peak in early winter, Jin and Timmermann said. In fact, the name El Nino, which translates to "the child," refers to Christmas, its traditional peak.

That should trigger larger than normal North Shore surf.

"We’ll have higher waves, better conditions for the pro surfers," Timmermann said.

"During a typical El Nino, California sees more rainfall, but if the rain comes down in torrential downpours, it could be destabilizing," he added.

By contrast, Indonesia and western Australia could see drought.

As the water moves eastward, the sea level will drop around Samoa and Tonga and other parts of the western Pacific, possibly by more than a foot, exposing shallow reefs, Timmermann said.

"All the organic material on the reef starts to smell," he said. "The Samoans actually have a word for this: taimasa,’ smelly reef. They hate it."