La Nina returns, but weaker impact seen: UN weather agency

AFP Yahoo News 18 Nov 11;

The UN weather agency said on Thursday that La Nina, a phenomenon linked to flooding and drought, had re-emerged in the tropical Pacific since August but its impact is expected to be weaker this time.

"This La Nina is expected to persist through the end of this year and into early 2012, possibly strengthening to moderate intensity," said the World Meteorological Organisation in a statement.

"However, it is likely to be considerably weaker than the recent episode that was linked to flooding and drought in different parts of the world."

La Nina is characterized by unusually cool ocean surface temperatures in the central and eastern tropical Pacific.

It is the opposite of El Nino, which is marked by unusually warm ocean surface temperatures.

Both factor in the fluctuations of the world's climate.

In late 2008 La Nina was blamed for icy conditions that claimed dozens of lives across Europe.

The weather phenomenon can also bring about strong rainfall in Indonesia, Malaysia and Australia, as well as drought in South America.

The current La Nina follows closely behind the moderate to strong one that started in September 2010 and ended with neutral conditions established in May this year, the WMO said.

"Historical precedents and the latest outputs from forecast models suggest that peak intensity of this La Nina will be reached in late 2011 or early 2012, and that it is very unlikely to reach conditions as strong as those of the 2010-11 La Nina event," the statement said.


La Nina Weak For Now But Likely To Strengthen: WMO
Stephanie Nebehay PlanetArk 18 Nov 11;

La Nina, a weather phenomenon usually linked to heavy rains and flooding in the Asia-Pacific and South America and drought in Africa, has re-emerged and is likely to persist into early 2012, the World Meterological Organization (WMO) said on Thursday.

However, it is "very unlikely" to reach conditions as strong as those of the 2010-2011 La Nina event that ended in May, the United Nations agency said.

"This La Nina is expected to persist through the end of this year and into early 2012, possibly strengthening to moderate intensity," the WMO said in a statement.

El Nino, its opposite weather phenomenon which warms the Pacific, has been ruled out as occurring before April 2012, according to the agency whose assessment is based on input from climate prediction centers and experts around the world.

(Editing by Keiron Henderson)