El Nino returns, likely will intensify into a strong event this year, NOAA says

The National Oceanic and Atmospheric Administration (NOAA) issued an El Niño Advisory on Thursday, confirming the presence of El Niño conditions and forecasting their likely intensification into a strong event by fall 2026. There is a 63% chance of a very strong El Niño developing between November 2026 and January 2027, potentially ranking among the strongest on record. NOAA emphasizes that stronger El Niño events increase the likelihood of extreme weather impacts, such as drought, heavy rainfall, and heatwaves, though they do not guarantee these outcomes. El Niño refers to the warmer-than-average phase of the El Niño–Southern Oscillation (ENSO), a natural cycle involving sea surface temperature fluctuations in the central and eastern equatorial Pacific Ocean. NOAA classifies El Niño events as weak, moderate, strong, or very strong based on temperature anomalies, while rejecting informal terms like 'super' or 'extreme' for operational forecasts. The World Meteorological Organization (WMO) aligns with this classification system. Forecasters report increased confidence in a strong El Niño due to the passage of spring in the Northern Hemisphere, a transitional period that previously reduced model accuracy. The WMO’s Secretary-General, Celeste Saulo, urged preparedness for potential exacerbation of drought, heavy rainfall, and heatwaves on land and in oceans. Meanwhile, Dr. Tim Stockdale of the European Centre for Medium-Range Weather Forecasts (ECMWF) noted that climate warming complicates El Niño measurements, as rising baseline ocean temperatures can distort anomaly readings. To address these challenges, NOAA and ECMWF introduced the Relative Oceanic Niño Index (RONI) this year, comparing central Pacific sea surface temperatures to global tropical ocean conditions rather than historical data alone. This adjustment aims to mitigate the effects of long-term ocean warming on El Niño assessments. The WMO clarified that there is no evidence climate change increases the frequency or intensity of El Niño events, though it makes their measurement more complex. El Niño events typically occur every 2 to 7 years, alternating with cooler La Niña phases. The updated RONI index and improved forecasting models now provide clearer insights into potential impacts, including disruptions to the upcoming hurricane season and global temperature trends. NOAA and the WMO continue to monitor developments closely to refine predictions and mitigate risks.