Unusual weather across the U.S. and other parts of the world just became more likely for this summer and autumn. That’s because the chances have gone up that El Niño—an atmospheric pattern driven by water temperature changes in the Pacific Ocean—will develop during that time, according to the nation’s leading climate experts. When El Niño settles in, it has major effects on weather conditions nationally and globally.



Scientists speaking at a press conference yesterday afternoon said the odds that El Niño will develop during the summer have risen from 65 to 70 percent. The prediction comes in a new monthly report from the U.S. National Weather Service and the International Research Institute for Climate and Society at Columbia University. The experts also said there is up to an 80% chance that El Niño will develop during the fall and winter.



Regions across the U.S. that are normally wet can dry out during El Niño conditions, while normally dry regions can flood. Worldwide expectations related to El Niño are not always accurate, however. “There is an expectation of drought, but not in every single El Niño event do we actually have drought,” Lisa Goddard, director of the International Research Institute for Climate and Society, said during the briefing.



In fact, the majority of the continental U.S. has a higher chance of experiencing above-average precipitation in both summer and fall of El Niño years, according to data from the U.S. National Oceanic and Atmospheric Administration. In addition, data from Golden Gate Weather Services, a consultancy in California, show particularly increased amounts of precipitation for southern California in stronger El Niño years, which could potentially help drought-stricken areas there and in other parts of the U.S. Southwest.



Regardless of the pros and cons, El Niño events could strengthen further as global warming continues, climate experts say. Two studies published within the last year generally support the conclusion that El Niño is increasing in intensity due to global warming, according to Kim Cobb, associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.



How strong the 2014 El Niño will become is unclear. Gerald A. Meehl, senior scientist in the Climate and Global Dynamics Division at the U.S. National Center for Atmospheric Research, said that if it does turn out to be strong, there could be a greater chance of a new record global average temperature in 2015.



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