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Is La Nina On Its Way?

Just when you thought the El Nino weather problems were easing, the climate could be heading into its also-threatening opposite, La Nina.

Storm-battered California and other regions where El Nino has disrupted the weather will be glad to see it end.

But El Nino years tend to reduce hurricane damage in the East -- only one made land last year -- so a return to normal or worse could portend deaths and damage on the Atlantic and Gulf coasts.

Just last week the World Meteorological Organization reported that El Nino "is in its dying stages" but said there is much uncertainty about how long it has left.

Meanwhile, climate and weather experts are waiting and wondering what is going to happen in the Pacific Ocean, which can greatly effect conditions around the world.

The National Center for Atmospheric Research will serve as host for the world's first summit devoted to La Nina, El Nino's less-studied counterpart, July 15-17.

El Nino occurs when the eastern Pacific Ocean near the coast of South America becomes unusually warm. That warm water generates rising moist air which can disrupt the powerful jet stream high in the atmosphere, resulting in changes in weather around the world.

In La Nina, this pool of water cools below normal, a change that also affects air patterns but is less well understood.

Normal sea-surface readings off South America's west coast range from the 60s to 70s Fahrenheit. In an El Nino they exceed 80 degrees, but during La Nina, the easterly trade winds strengthen, cold upwelling off Peru and Ecuador intensifies, and sea-surface temperatures there fall as much as 7 degrees below normal.

Like its counterpart, La Nina tends to be strongest during the Northern Hemisphere winter, and it typically lasts one to two years.

La Nina's effects include the 1988 Midwest drought and an increased hurricane threat in the Atlantic Ocean and Gulf of Mexico.

After an El Nino the climate usually returns to normal, not always swinging into the La Nina condition. In the past 20 years there have been only three La Ninas, compared to seven El Ninos.

Monday, the government's top forecasters issued their latest El Nino update at the White House, accompanied by Vice President Al Gore, James Lee Witt, who runs the Federal Emergency Management Agency, and officials from the National Oceanic and Atmospheric Administration.

An analysis by government scientists has found record-breaking global temperatures in each of the first five months of 1998. During those months, the average global surface temperature was 1.76 degrees above an average of 61.7 degrees for the benchmark period of 1961 to 1990.

Gore, noting the temperature records, said "it appears that this general warming trend is making the effects of El Nino worse. This is a reminder once again that global warming is real and that unleswe act we can expect more extreme weather in the years ahead."

Across town, however, a top official of the Pan American Health Organization said scientists have been unable to substantiate concerns that El Nino would lead to increases in disease.

"We found no correlation between the number of reported communicable diseases and the recurrence of El Nino" over recent decades, Claude de Ville de Goyet told an American Geophysical Union workshop on the ocean's role in human health.

"I don't say they are not possible, I say we found no correlation," said the health organization's chief of emergency preparedness.

El Nino was named more than a century ago by Peruvian fishermen who tend to first notice its effects around Christmas time. The name is Spanish for "little boy," referring to the Baby Jesus. The La Nina phase remained unnamed until the mid-1980s, when it was given the name meaning "little girl."

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