By Tom Miles
GENEVA (Reuters) - The current El Nino weather phenomenon is expected 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.
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.
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.
"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 Program.
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 the frequency or magnitude of El Nino events.
Since 1950, strong El Nino events occurred in 1972-3, 1982-3 and 1997-8.
(Reporting by Tom Miles; Editing by Raissa Kasolowsky)