The chances of a La Nina developing this year have increased to 50 percent as the Pacific Ocean cools, according to Australia’s government forecaster, which upgraded its outlook for the weather pattern to “watch.”
Five of eight climate models surveyed suggest La Nina is likely by spring, with three neutral, the Bureau of Meteorology said on its website on Tuesday. Australia’s spring starts in September. A La Nina watch means there is about a 50 percent chance of the pattern developing in 2016, about twice the normal likelihood, it said.
La Nina weather, which cools the equatorial Pacific Ocean, is sometimes thought of as El Nino’s opposite. The two are extreme phases of a naturally occurring cycle, according to the National Oceanic and Atmospheric Administration. Forecasters from Japan to the U.S. and Indonesia have predicted a La Nina could develop this year, potentially changing weather globally.
“While the current El Nino is expected to persist until late autumn or early winter, there are early signs that the chance of a La Nina developing by spring 2016 has increased,” the Australian bureau said. “La Nina watch criteria have been met following expert assessment of the steady cooling in the surface and sub-surface of the tropical Pacific Ocean and updated model outlooks indicating increased likelihood of cooling to La Nina thresholds by spring 2016.”
The 2015-16 El Nino remains weak to moderate and is expected to return to neutral levels by mid-2016, the bureau said. The current event is the strongest since the record 1997-98 El Nino and has reduced Indian rainfall, parched farmland in Asia and curbed cocoa production in West Africa.
La Nina can also roil agricultural markets as it changes weather. More rain could fall across Indonesia and parts of Australia and Brazil. At the same time, the U.S. Great Plains, Rocky Mountains and Florida could get less. The previous La Nina began in 2010 and endured into 2012.