El Nino Signs Re-Emerge as Weakening Trade Winds Warm Pacific

Aug 12, 2014 2:16 am ET

Aug. 12 (Bloomberg) -- The Pacific Ocean has shown renewed signs of a developing El Nino weather pattern, which brings drought to Asia and heavy rains in South America, after trade winds weakened, according to Australia’s weather forecaster.

The chance of the event this year is at least 50 percent, with five of eight climate models suggesting the pattern is likely during the spring, which starts in September, the Bureau of Meteorology said in an update on its website today. If the phenomenon was to occur, it is unlikely to be strong, it said. The bureau maintained a watch for the weather pattern.

El Ninos can roil agricultural markets as farmers contend with drought or too much rain. Palm oil, cocoa, coffee and sugar are among crops most at risk, according to Goldman Sachs Group Inc. The U.S. last week lowered the odds of the pattern developing this year and forecast that the event will be weak.

“Some warming has occurred in the central and eastern equatorial Pacific Ocean in the recent fortnight, due to a weakening of the trade winds,” the Melbourne-based forecaster said. “If the trade winds remain weak, more warming towards El Nino thresholds is possible.”

The odds of the pattern fell to about 65 percent during the Northern Hemisphere fall and early winter, the U.S. Climate Prediction Center said Aug. 7. Last month, the probability was almost 80 percent. The chances of the phenomenon occurring this autumn and winter are lower than earlier projections, the Japan Meteorological Agency said yesterday.

Weak Event

The approximate 30-day Southern Oscillation Index to Aug. 10, which indicates the development and intensity of El Nino or La Nina events, was minus 5.2, according to Australia’s weather bureau. Sustained negative values below minus 8 may indicate an El Nino event, according to the bureau.

The pattern will probably develop as a weak event in late summer or early fall, according to MDA Weather Services. Commodity Weather Group LLC said last month that it may be delayed for several months as Pacific Ocean warming slows.

El Ninos, caused by periodic warmings of the tropical Pacific, occur every two to seven years and are associated with warmer-than-average years. The last El Nino was from 2009 to 2010, and the Pacific has either been in its cooler state, called La Nina, or neutral since then.