Boston: A La Nina could begin as soon as summer in the Northern Hemisphere as one of the strongest El Ninos on record keeps weakening in the equatorial Pacific Ocean.
La Nina is a cooling of the ocean’s surface, in contrast to the warming that characterizes an El Nino. Both phenomena can alter global weather patterns, even affecting the number of hurricanes that develop in the Atlantic.
“We are still technically in an El Nino but we are seeing a lot of cold water bubbling up near the coast of South America,” said Michelle L’Heureux, a forecaster with the US Climate Prediction Center in College Park, Maryland. “It is not widespread at this point, but it is indicative to a transition and a fairly quick one.”
More hurricanes tend to develop in the Atlantic in a La Nina year because it cuts down on wind shear across the basin that can rip budding storms apart. Strong La Ninas also threaten to bring drier conditions across agricultural areas of southern Brazil and flooding to parts of Australia.
The center isn’t making forecasts on the strength of the La Nina yet, in part because many predictive models aren’t always as accurate during spring in the Northern Hemisphere. US forecasters believe there is a 75% chance a La Nina will form by the end of 2016, and they are favouring it to develop over the summer, L’Heureux said.
Earlier this week, Australia’s Bureau of Meteorology maintained its La Nina watch and said there was a 50% chance it could form by the end of the year. Bloomberg