This year's El Nino weather pattern could be strongest on record: experts

Tom Miles Reuters Yahoo News 2 Sep 15;

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)

Current El Nino climate event 'among the strongest'
Matt McGrath BBC News 2 Sep 15;

The current El Nino weather phenomenon could be one of the strongest on record, according to the World Meteorological Organization (WMO).
The event occurs when the waters of the Pacific become exceptionally warm and distort weather patterns around the world.

Researchers say parts of the Pacific are likely to be 2C warmer than usual.

The WMO says that this year's event is strengthening and will peak by the end of this year.

The strongest El Nino on record was in 1997-98, but there were events that were significantly above the norm in 1972-73 and again ten years later in 1982-83.

Scientists say that the event now underway is sending sea temperatures in parts of the Pacific to levels not seen since the late 1990s.
In a statement the WMO said that this El Nino was gathering strength.

"Models and expert opinion suggest that surface water temperatures in the east-central tropical Pacific Ocean are likely to exceed 2C above average, potentially placing this El Nino event among the four strongest events since 1950," it said.

The WMO says that patterns of cloudiness and rainfall near the international dateline developed during the second quarter of this year and have been well maintained.

These patterns are considered essential in triggering El Nino's global climate impacts which are more likely to be felt over the next six to eight months.

"Compared to the last major El Nino event in 1997-1998, there is much more information available," said Maxx Dilley from WMO.
"We have better models and are much more prepared."

"It is a test case for the early warning systems and climate information systems of WMO members and we are hoping that will be of assistance to some of the affected countries," said Mr Dilley

The phenomenon can alter established weather patterns in different parts of the world, bringing severe drought to parts of Asia while at the same time bringing heavy flooding to some parts of North America.

It can increase flooding in the Horn of Africa while making Southern Africa drier.

The events are likely to lead to a decrease in storm events in the Atlantic and the Gulf of Mexico and an increase in storminess in the eastern Pacific.

This El Nino has also impacted the South Asian monsoon.

"We are seeing that the Indian monsoon right now is almost 12% below normal. There is only a month left of the summer monsoon season making it difficult to recover," said WMO's El Nino expert Rupa Kumar Kolli.

"That was the kind of early warning information we can extract from the El Nino signal and it helps policy makers to prepare," he said.
Currently, the Pacific is seeing a surge of hurricane activity, with three category four strength tropical storms swirling around the Hawaiian islands.

Researchers say that these hurricanes can disrupt the predominant easterly trade winds that are found along the equator. This disruption allows more heat to build up in the eastern part of the Pacific, adding more fuel to stormy conditions.

But researchers cautioned that the scale of impacts, especially in the northern hemisphere, is very hard to read because there is also an Arctic warming effect seen in the Atlantic jet stream.

"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," David Carlson, the director of the World Climate Research Programme, told news agencies.