El Nino to influence climate patterns to midyear-WMO

GENEVA, (Reuters) – The El Nino warming the Pacific  Ocean since June has peaked, but is expected to influence  climate patterns worldwide up to mid-year before dying out, the  World Meteorological Organisation (WMO) said yesterday.

However, the United Nations agency said that forecasting  uncertainties meant it could not rule out the possibility that  El Nino would persist beyond mid-year.

El Nino, driven by an abnormal warming of the eastern  Pacific Ocean, can create havoc in weather patterns across the  Asia-Pacific region, unleashing droughts in some places and  heavy storms in others. It typically lasts from 9 to 12 months.

The most likely scenario is for sea surface temperatures  across the tropical Pacific, which rose by 1.5 degrees Celsius  at its peak last November-December, to return to normal by  mid-2010, WMO said in a statement.

“El Nino is already in a decaying phase. We expect it to  fully decay by mid-year and neutral conditions to be  established,” WMO climate expert Rupa Kumar Kolli told Reuters.

“But this is a period where the predictability of the system  is very low. Things could happen very suddenly,” he said.

The WMO said that the current El Nino, which can occur every  two-seven years, was of a moderate level, “close to or slightly  above the typical strength seen in the historical record of El  Nino events.”

“Even during the decaying phase of the El Nino, expected  over the next few months, the conditions associated with a  typical El Nino will continue to influence climatic patterns at  least through the second quarter of the year,” it said.

El Nino typically creates dry conditions for western areas  along the Pacific Ocean such as South East Asia and Indonesia,  and southern parts of western Australia, and wetter than normal  conditions in western coastal areas of South America, Kolli told  Reuters.

Parts of South Asia experienced drought last year due to a  weak summer monsoon season linked to El Nino, and this could  happen again if El Nino were to intensify in June, he said.

“That is the typical signature of El Nino,” he added.

Warmer sea temperatures along some coastal regions of Latin  America had caused higher rainfalls, but these were confined to  relatively smaller pockets, and did not wreak havoc, he said.

The last severe El Nino in 1998 killed more than 2,000  people and caused billions of dollars in damages to crops,  infrastructure and mines in Australia and Asia.

“Every El Nino is an individual event,” Kolli said.

However, the phenomenon, which means “little boy” in  Spanish, referring to the Christ child because it is often  noticed mostly clearly in Latin America around Christmas, is  also linked to a weaker than normal hurricane season in the  northern Atlantic, according to the WMO expert.

The opposite cooling phenomenon, known as La Nina, or  “little girl,” could also start in the middle of this year, but  that scenario is deemed less likely.