UPDATE 1-This year's El Nino weather pattern could be strongest on record - experts

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By Tom Miles
GENEVA, Sept 1 (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 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 the frequency or magnitude of El Nino events.
Since 1950, strong El Nino events occurred in 1972-3, 1982-3
and 1997-8.