Potential Effects of Strong El Niño on U.S. Weather

A historic El Niño event is anticipated to strengthen significantly, raising concerns about its impact on U.S. weather patterns this winter. Federal forecasters noted on Thursday that the likelihood of a strong El Niño during fall and winter through 2026 has increased, with a greater than 90 percent probability it will become exceptionally intense.

Understanding El Niño

El Niño represents the warm phase of the El Niño-Southern Oscillation (ENSO), a recurring Pacific climate pattern that influences weather globally. La Niña, its counterpart, marks the cycle’s cool phase. El Niño typically results in stormier weather in the Southern U.S., drier conditions in northern areas, and alterations in hurricane activity.

The National Oceanic and Atmospheric Administration’s Climate Prediction Center updated its El Niño forecast, indicating a 75 percent chance of reaching historic strength between October and December. This likelihood increased from the 69 percent noted in August. While significant El Niño weather impacts are likely, they aren’t guaranteed.

Potential Winter Impacts

AccuWeather expert Paul Pastelok shared insights with Newsweek, forecasting potential heavy rainfall in central and Northern California and snow in the Sierras come December. The Northeast could also see substantial precipitation. Another storm track might emerge from the Gulf Coast through the Mid-Atlantic, influencing rain and thunderstorms in the Southeast and Mid-Atlantic. Mild conditions are anticipated for the Great Lakes, Midwest, and Northeast relative to averages.

During January and February, Pastelok predicts strong storm tracks hitting the West Coast, particularly California and Nevada, extending into the Four Corners region. Reduced snowfall and cold air masses might occur in the Northwest and northern parts of the nation. Continued wet and stormy weather is possible for the Gulf Coast, Mid-Atlantic, and Southeast.

Pastelok acknowledged that other factors could alter this El Niño pattern and noted ongoing research by AccuWeather.

Climate Predictions

Recent maps from the Climate Prediction Center (CPC) outline temperature and precipitation forecasts for December 2026 to February 2027. Temperature outlooks suggest above-normal conditions across a considerable part of the U.S., especially the northern tier, Pacific Northwest, and northern Rockies through the Plains, Midwest, and Northeast. Southern U.S. temperatures are similarly expected to be warmer than usual, although California and the Southwest are less clear-cut.

Precipitation forecasts by CPC favor wetter-than-normal conditions for Southern California, the Southwest, southern Plains, Gulf Coast, Florida, and parts of the East Coast.