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FILE: Workers maintain their picket lines in San Francisco despite rain showers on Nov. 11, 2024.\u00a0<\/p>\n
Charles Russo\/SFGATE<\/p>\n
As signs of El Ni\u00f1o<\/a> brew in the Pacific Ocean, forecasters are closely tracking not only when the seasonal climate pattern could officially emerge but also just how strong it could become.<\/p>\n There is a 61% chance that El Ni\u00f1o conditions will begin between May and July and last at least through the end of the year, the National Weather Service\u2019s Climate Prediction Center said on Thursday<\/a>. La Ni\u00f1a, which began last fall<\/a> and reigned over the recent winter, just ended.<\/p>\n Article continues below this ad<\/p>\n The new outlook also found a 25% chance of a \u201cvery strong\u201d El\u00a0Ni\u00f1o developing.<\/p>\n \u201cThe forecast has been homing in on what looks like a good-sized El Ni\u00f1o event,\u201d Alexander Gershunov, a research meteorologist at Scripps Institution of Oceanography at UC San Diego, told SFGATE. \u201cBut of course, there\u2019s a big spread in model predictions, so it could still be anything from neutral conditions to a very strong El Ni\u00f1o.\u201d<\/p>\n El\u00a0Ni\u00f1o is the warm phase of a pattern that develops in the tropical Pacific Ocean, called the El Ni\u00f1o-Southern Oscillation, or ENSO. During El Ni\u00f1o events, weak trade winds are associated with above-average surface temperatures in those waters. The other phase, La\u00a0Ni\u00f1a, brings stronger winds that promote cooler ocean conditions. The pattern alternates irregularly, with neutral phases in between.<\/p>\n Make SFGATE a preferred source so your search results prioritize writing by actual people, not AI.<\/p>\n <\/p>\n Add Preferred Source<\/p>\n <\/a><\/p>\n El Ni\u00f1o and La Ni\u00f1a bring a cascade of global weather impacts. In California, people often assume<\/a> that El Ni\u00f1o brings a wet winter and La Ni\u00f1a, a dry one. Not only does the El Ni\u00f1o pattern tip the odds in favor of a wetter season, especially in Southern California, but endless rain from the El Ni\u00f1o winters such as 1997-98<\/a> loom large in collective memory.\u00a0<\/p>\n Article continues below this ad<\/p>\n Yet scientists have to come to appreciate that El Ni\u00f1o years can lead to a variety of outcomes locally.\u00a0In the winter of 2015-2016, for example, the infamous \u201cGodzilla<\/a>\u201d El Ni\u00f1o \u2014 one of the strongest ever recorded \u2014 did not deliver the expected precipitation in Southern California.<\/p>\n Michelle\u00a0L\u2019Heureux, who leads the ENSO team at the Climate Prediction Center, explained the potential significance of a stronger El Ni\u00f1o.<\/p>\n \u201cThe advantage of seeing stronger El Ni\u00f1os (vs. weaker events) is that we generally see a pattern of weather and climate impacts over the globe that looks more like what is expected during El Ni\u00f1o,\u201d L\u2019Heureux wrote to SFGATE. She added, \u201cWith that said, especially since you are in California, it is important to keep in mind that even the strongest El Ni\u00f1os in our record do not always appear exactly as anticipated.\u201d<\/p>\n Since 1950, there have only been five strong El Ni\u00f1os and five very strong El Ni\u00f1os, L\u2019Heureux said. These strength categories refer to how much sea surface temperatures depart from normal in the east-central tropical Pacific, L\u2019Heureux explained. \u201cIt does not necessarily mean that the El Ni\u00f1o impact will be stronger over a particular location\u2014 our outlooks will only provide a tilt in the odds for certain outcomes to occur. Even stronger El Ni\u00f1o\u00a0events will never provide guaranteed outcomes\u2014 it can only favor certain outcomes,\u201d she wrote.\u00a0<\/p>\n Article continues below this ad<\/p>\n<\/p>\n