El Nino seen developing in September-October: U.N. weather body

Stephanie Nebehay PlanetArk 26 Sep 12;

An El Nino event, usually associated with significant changes in rainfall, is likely to develop this month and next in the Pacific, affecting global climate patterns, the World Meteorological Organization (WMO) said on Tuesday.

The phenomenon, characterized by unusually warm ocean temperatures in the tropical Pacific, has been linked previously to drier-than-normal conditions in Australia, Indonesia, the Philippines, northeastern Brazil, southeastern Africa and parts of Asia, the United Nations agency said.

"A weak El Nino may develop in September and October and last until the northern hemisphere winter," the WMO said in a statement.

El Nino is also associated with wetter-than-normal conditions in Ecuador, northern Peru, southern Brazil to central Argentina and parts of eastern Africa, it said.

El Nino winters tend to be mild over western Canada and parts of the United States and wet over the southern United States, it added.

La Nina, its opposite phenomenon which causes an abnormal cooling of waters, ended in April.

The WMO update is based on many different climate forecast models gathered from centers around the world.

"The majority of these climate forecast models say that there is a 'moderately high likelihood' of an El Nino. Having said that, it can't be ruled out that neutral conditions may continue," WMO spokeswoman Clare Nullis told a news briefing.

The Geneva-based WMO promotes cooperation among its 189 member states and their national meteorological and hydrological services and is the U.N. system's voice on weather, climate and water.

(Reporting by Stephanie Nebehay; editing by Jason Neely and Anthony Barker)

Lower chance of El Nino, but risks remain: Australia
Colin Packham PlanetArk 26 Sep 12;

Tropical Pacific Ocean temperatures indicating the onset of an El Nino have eased over the last two weeks, reducing the chance of the weather event emerging, the Australian Bureau of Meteorology said on Tuesday.

However, the bureau warned the risk of an El Nino -- which can trigger drought in Australia, Southeast Asia and India and floods in parts of South and North America -- returning remained.

Pacific Ocean temperatures had cooled in the last fortnight, while other indicators remained in neutral territory, it said.

The bureau said that despite the change in indicators conditions continued to favor below average rainfall over much of Australia in the southern hemisphere spring.

"We are seeing the Indian Ocean showing a pattern that would bring drier conditions to at least central and south east Australia," Andrew Watkins, manager of climate prediction at the weather bureau's National Climate Centre said.

"That signal is a little stronger than the El Nino signature in the Pacific is showing."

Japan's weather bureau said on September 10 its climate models indicated the El Nino phenomenon was under way and there was a high chance it would last until winter.

El Nino can cause above average rains in northern Peru and Bolivia, drought in Southeast Asia, Australia, India and northeast Brazil, cyclones in the central Pacific and stormy weather in the southern and western United States.

The worst El Nino on record in 1997/98 killed more than 2,000 people and caused property damage estimated at $33 billion. The pattern can also cause serious damage to crops such as wheat in Australia due to drought.

(Reporting by Colin Packham; Editing by Ed Davies)