Chatter about this year's Super El Niño and how that will influence our winter season has been loud across social media. First off, we need to talk about what El Niño is. It is a weather pattern caused by warmer ocean waters off the coast of South America. When you hear "super" El Niño, that is referencing when sea surface temperatures in that region are 2.0°C above normal. This year, that intensity will be more than 3.0°C above normal, not necessarily that our local temperatures will be that far above average.
A typical El Niño pattern often results in milder than average temperatures, with around normal precipitation amounts. The warmer waters off the South America coastlines often push the Pacific jet stream along the Southern parts of the country, while the Polar jet takes a more Northwest track. This could limit the number and strength of big winter storms but may lead to an increase in quicker moving clipper systems from the Northwest.
How do our past El Niño winters compare to average? Meteorological winter runs from December 1st through February 28th, so all of these numbers below are averages across that time span. Typically, Rockford's normal winter will bring an average temperature of 24.2 degrees with 4.76" of measurable precipitation, and 29.2" of snowfall.
Two years in which the El Niño strength is comparable to this year were the winters of 1997-98 and 2015-16. In 1997-98, that winter saw a warmer than average trend with about normal precipitation and below average snowfall. The winter of 2015-16 saw another warm winter with below average snowfall. A simple analog forecast may come to a similar conclusion, but there are other factors that go into a winter forecast besides just what stage of El Niño we are seeing. But when El Niño is this strong, it may become the more dominant overarching pattern.
The National Oceanic and Atmospheric Association (NOAA) has put out their winter forecast, which closely resembles a typical El Niño pattern. Locally across the upper Midwest, we will likely see a warmer than average winter with equal chances of above average or below average precipitation. How that translates to individual snowfall events is not a direct correlation, so we will likely still see several instances of snow, potentially some heavy at times. But the frequency of those storms may be a bit lower compared to historical averages.
My personal forecast for Rockford this winter 2026-27 is that we will see above average temperatures, near average to just below average precipitation, and below average snowfall. But again, I want to emphasize that the 3.0°C above average you read about is NOT correlated exactly to what we will see locally.
It is also worth noting that Rockford has not seen a "typical" season of snowfall since the winter of 2020-21. Every winter since then has been below average, with the highest season of snowfall during that time receiving just below 20" of snow during the winter of 2023-24. Snow lovers may again have to wait another winter before we see abundant snowfall.
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