A “super” El Niño is now 95% likely to develop this year as the climate pattern gains dramatic strength in the Pacific Ocean — leaving officials across California and beyond bracing for a wet and potentially destructive winter.
The National Oceanic and Atmospheric Administration’s Climate Prediction Center said Thursday that El Niño has strengthened in the past month, and there’s about a seven-in-10 chance it will be the strongest such pattern since 1950.
Of the three other powerful El Niños on record during that span — in 1982-83, 1997-98 and 2015-16 — two brought above-average rain to Southern California. The 2015-16 El Niño, while very strong in the ocean, did not, though the pattern was blamed for record beach erosion along the California coast.
El Niño is a climate pattern characterized by warmer ocean waters in the central and eastern tropical Pacific, coupled with changing atmospheric conditions, in which the typical east-to-west trade winds weaken or even reverse.
That shift can put Southern California in the crosshairs of potentially potent tropical moisture, though the pattern’s effects vary by area.
In the modern historical record, past El Niños have never been warmer than 4.5 degrees above baseline. But there is now a 69% chance that this El Niño will reach or exceed that threshold in the tropical Pacific.
That “has never happened in our historical record dating back to 1950,” Michelle L’Heureux, the El Niño team lead for NOAA’s Climate Prediction Center, told The Times.
The last record set was during the 1982-83 El Niño season, where the Relative Oceanic Niño Index was 4.32 degrees above baseline.
The most powerful type of El Niño is officially designated as “very strong,” though it’s often referred to as a “super” El Niño. Reaching that threshold requires temperatures in the equatorial Pacific to be at least 3.6 degrees above baseline.
For the three-month period of October, November and December, NOAA’s Climate Prediction Center forecasts a 95% chance that El Niño will be “very strong,” and a 5% chance it will merely be “strong.”
Historically, the effects of El Niño on Southern California’s rainfall and snowfall become more obvious from December onward, with January to March “as the prime season for impacts,” L’Heureux said.
So far, there’s no conclusive evidence that El Niño is affecting the West Coast, NOAA research oceanographer Michael Jacox told The Times. The California coast is, however, being affected by a marine heat wave that isn’t currently related to El Niño, especially in Southern California, which experts say is a factor in the mugginess being felt along some coastal areas.
“But we are into the time of year now when El Niño’s impacts could be felt any time; this initial impact should be due to coastal trapped waves coming from the south,” Jacox said.
When looking at July alone, ocean temperatures in the equatorial Pacific are the second-highest for the month on record, according to L’Heureux. Temperatures in the area of the ocean used to calculate El Niño were already 2.41 degrees above baseline.
The only July in modern times where that reading was stronger was in 1997, when the ocean temperatures there were 2.74 degrees above the baseline.
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