March 25 (Bloomberg) -- The chances of an El Nino weather pattern, which can parch parts of Asia and bring rains to South America, occurring this year have increased, according to Australia’s Bureau of Meteorology.
Climate models show that the tropical Pacific Ocean is likely to warm in coming months, with most models predicting sea surface temperatures reaching El Nino thresholds during the southern hemisphere winter, the bureau said today.
The Southern Oscillation Index, which indicates the development and intensity of El Nino or La Nina events, dropped to minus 12.6, the lowest 30-day value since March 2010 and seen during the last El Nino, it said. Sustained negative values below minus 8 may indicate an El Nino.
El Nino affects weather worldwide and can roil agricultural markets as farmers contend with drought or too much rain. The phenomenon often touches off warmer winters across the northern U.S., heavier rains from southern Brazil to Argentina and drier conditions across Southeast Asia and eastern Australia. It also can lead to a calmer Atlantic hurricane season and a stormier winter in the U.S. South.
“Following two strong westerly wind bursts since the start of the year, waters below the surface of the tropical Pacific have warmed significantly over the past two months,” the weather bureau said. “This has led to some warming at the surface, with further warming expected in the coming weeks.”
The U.S. Climate Prediction Center issued an El Nino watch this month. There’s a 52 percent chance that the Pacific Ocean will warm enough to trigger the weather pattern late this summer or in early fall, according to climate scientist Michelle L’Heureux. The chances of El Nino emerging later in the northern hemisphere summer are 75 percent, according to Donald Keeney, senior agricultural meteorologist at MDA Weather Services.
The last El Nino occurred in 2009 to 2010, and since then the other two phases of the cycle, a cooling called La Nina and a period of neutral conditions, have held sway, according to the Climate Prediction Center. Rubber, sugar, coffee, and natural gas are among the commodities that can fluctuate because of an El Nino, which usually occurs every three to five years and can last for months.
The pattern is usually associated with below-normal rain across large parts of southern and inland eastern Australia in the second half, the bureau said. Daytime temperatures also tend to be above-normal in southern areas, it said.
A record 79 percent of Australia’s Queensland state is in drought, threatening cotton and sugar production and boosting cattle slaughter. Rubber output in Thailand, Indonesia and Malaysia is set to drop 6 percent to 8 percent this year because of dry conditions, according to the International Rubber Consortium Ltd. Dry weather parched oil-palm trees in Indonesia and Malaysia this year.
El Nino typically creates very ideal growing conditions in the U.S. Midwest during the summer, Art Douglas, meteorologist at Creighton University in Omaha, Nebraska, said Feb. 5.
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