Science

This year's El Nino will be the strongest in 18 years, WMO says

The current El Nino weather phenomenon is expected to peak between October and January and could turn into one of the strongest on record, experts from the World Meteorological Organization say.

World Meteorological Organization predicts El Nino peak between October and January

A father with his children walk over the cracked soil of a 1.5 hectare dried up fishery at the Novaleta town in Cavite province, south of Manila in May. El Nino is leading to dry weather in Southeast Asia. (Romeo RanocoReuters)

The current El Nino weather phenomenon is expected to peak between October and January and could turn into one of the strongest on record, experts from the World Meteorological Organization said at a news conference on Tuesday.

Climate models and experts suggest surface waters in the east-central Pacific Ocean are likely to be more than 2 degrees hotter than average, potentially making this El Nino one of the strongest ever.

The forecast from the United Nations weather agency is consistent with what the U.S.-based National Oceanic and Atmospheric Administration has been predictiing.

Typically, the warm air above the eastern Pacific is causing increased precipitation over the west coast of South America and dry conditions over the Australia/Indonesia archipelago and the Southeast Asia region, said Maxx Dilley, director of the WMO's Climate Prediction and Adaptation Branch.

El Nino can also bring higher rainfall and sometimes flooding to the Horn of Africa, but causes drier conditions in southern Africa, Dilley said.

Arctic warming effect unknown

Climate scientists are better prepared than ever with prediction models and data on El Nino patterns, but the impact of this El Nino in the northern hemisphere is hard to forecast because there is also an Arctic warming effect at work on the Atlantic jetstream current.

Warm air above the eastern Pacific as a result of El Nino is causing increased precipitation over the west coast of South America and dry conditions over the Australia, Indonesia archipelago and Southeast Asia region, said Maxx Dilley, director of the WMO's Climate Prediction and Adaptation Branch during a press conference Tuesday. (Salvatore Di Nolfi/Keystone via Associated Press)

"The truth is we don't know what will happen. Will the two patterns reinforce each other? Will they cancel each other? Are they going to act in sequence? Are they going to be regional? We really don't know," said David Carlson, the director of the World Climate Research Programme.

This El Nino could also be followed abruptly by a cooling La Nina, which, along with the advance of global warming, was adding to the uncertainty, Carlson said.

"I think we all think that there's some climate warming signals starting to show up in the El Nino record," he said.

But he added that it is still unclear how global warming is affected by the frequency or magnitude of El Nino events.

Since 1950, strong El Nino events occurred in 1972-3, 1982-3 and 1997-8.