Somewhere in the Cascade backcountry could be good again? Photo: Ben Kitching//Unsplash
The National Weather Service’s (NWS) Climate Prediction Center (CPC) released its most recent El Niño / Southern Oscillation (ENSO) update Thursday, a monthly update on observations of El Niño and La Niña conditions and how they impact long-range seasonal forecasts. The agency is continuing to call for a “weak” La Niña for the upcoming winter season which they expect to end between January and March.
“La Niña is expected to remain weak (three-month average Niño-3.4 index value at or between -0.5°C and -0.9°C),” the NWS wrote. “A weak La Niña would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance. In summary, La Niña is favored to continue into the Northern Hemisphere winter, with a transition to ENSO-neutral most likely in January-March 2026 (61 percent chance).”
The latest prediction isn’t far removed from the agency’s update last month, however, their confidence in La Niña’s transition to ENSO-neutral between January and March did slightly increase (from 55 percent in October).
What does this all mean? While forecasts of “weak” and “strong” El Niño or La Niña conditions might sound like markers of mild or extreme weather, they are also indicators of how well CPC forecasters can predict long-range weather conditions. La Niña is typically associated with higher winter snowfall totals in the northernmost parts of the United States and into Canada, dumping snow on places like the Pacific Northwest, for example. La Niña has the opposite impact on Southern California, meanwhile, while the Rockies also experience lower than average snowfall totals. A weak La Niña actually indicates that the historical patterns of La Niña conditions are less consistent.
A weak La Niña would be less likely to result in conventional winter impacts,” the CPC says.
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