El Niño odds rise sharply

The National Oceanic and Atmospheric Administration’s Climate Prediction Center said on May 14 that El Niño is likely to develop in May-July 2026 and continue through Northern Hemisphere winter 2026-27. The agency put the chance of emergence in May-July at 82% and the chance of El Niño persisting into December 2026-February 2027 at 96%, according to its latest ENSO Diagnostic Discussion. The update marked a faster shift than earlier spring outlooks, which had still favored neutral conditions into early summer. The World Meteorological Organization said on April 24 that an El Niño event was expected to develop from mid-2026, citing forecasts from global producing centers. ### How much did the forecast change in a matter of weeks? April forecasts were materially lower. NOAA’s official April 2026 ENSO probabilities showed a 61% chance of El Niño emerging in May-July 2026 and said it was likely to persist through at least the end of 2026. By the May 14 discussion, that May-July probability had risen to 82%, and the winter 2026-27 persistence probability had reached 96%. The International Research Institute for Climate and Society at Columbia University also showed the shift. Its latest plume-based outlook said El Niño had a 70% chance in April-June 2026 and remained the dominant outcome through the rest of 2026 at roughly 88% to 94%, while its March quick-look had shown El Niño probabilities only becoming the leading category from May-July onward. ### What are forecasters actually seeing in the Pacific? NOAA said weekly Niño 3.4 readings from mid-April to early May ranged from about +0.5 degrees Celsius to +0.9 degrees Celsius, above the standard El Niño threshold. The agency said oceanic and atmospheric conditions had become more consistent with an emerging warm event, even though the basin had only recently moved out of La Niña and into neutral conditions. The World Meteorological Organization said in its February 2026 update that neutral conditions were then the most likely outcome for spring and early summer. By April 24, WMO said the likelihood of El Niño had increased and that the event was expected to develop from mid-2026, reflecting newer model guidance. ### Is there official support for calling this a “super” El Niño yet? NOAA has not labeled the developing event a “super El Niño” in its official forecasts. The Climate Prediction Center’s May discussion said El Niño was likely to emerge and persist, but it did not assign a “super” classification or say the event would be historically extreme. NOAA’s Geophysical Fluid Dynamics Laboratory published May 2026 model forecasts showing a range of outcomes through April 2027, with stronger positive Niño 3.4 anomalies in some ensemble runs. Those model spreads show a path to a stronger event, but the official CPC discussion stops short of naming a peak intensity beyond saying El Niño is likely. ### Why are engineers and local planners paying attention now? A faster-developing El Niño matters because design assumptions for rainfall, runoff and coastal exposure are often set months before the wettest season arrives. El Niño is associated with shifts in temperature and rainfall patterns around the world, the WMO said, though local impacts vary by region and event strength. In the U.S. West, state and local agencies typically use seasonal outlooks, stormwater criteria and coastal hazard planning together rather than relying on ENSO alone. The current forecasts do not dictate a single design standard, but they do increase the value of tracking official updates as winter 2026-27 approaches. ### What should readers watch next? NOAA updates oceanic and atmospheric ENSO conditions weekly on the Climate Prediction Center website. The agency’s monthly ENSO Diagnostic Discussion is issued on a regular cycle, and those reports will show whether probabilities continue to rise and whether forecasters begin attaching stronger intensity language to the event. The next milestones are the June CPC outlook and subsequent WMO and IRI updates, which will show whether model agreement strengthens into late 2026 and early 2027.