An intensifying El Niño is increasing the risk of heavy rain in the southwestern United States, scientists told the Associated Press on November 2. The report followed Sunday flash floods that prompted evacuations in northern New Mexico and central Arizona, bringing renewed attention to weather risks extending into winter.
Experts cited by AP said unusually warm Pacific waters add atmospheric moisture and alter winds, helping storms develop. They cautioned that El Niño was not the only cause of the flooding and that attributing any individual storm to the phenomenon is difficult.
The broader outlook predates these latest floods. In its October 15 winter forecast, the US National Oceanic and Atmospheric Administration, NOAA, projected wetter conditions across the southern United States and East Coast for December 2026 through February 2027. Northern areas were expected to be warmer than average.
NOAA weather service director Ken Graham explained that a strong El Niño can move the jet stream southward and eastward, favouring southern storms. Additional precipitation may ease drought, but excessive rain on dry ground can trigger flash floods and mudslides. The agency's outlook describes seasonal probabilities rather than snowfall totals.
The World Meteorological Organization warned on October 21 that tropical Pacific surface temperatures could reach 3.8°C above average during November through January. It anticipated a peak around December, with effects lasting beyond it. Its outlook identified flood risks in parts of East Africa and threats to crops and water supplies from drier conditions in southern Africa.
WMO also highlighted heat and rainfall deficits in Southeast Asia, and urged governments and humanitarian agencies to prepare for vulnerable communities. It stressed that seasonal outlooks cannot predict individual events: regional and national forecasts remain essential. NOAA's next winter outlook update is scheduled for November 19.
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