La Niña Could Make Things Extra Snowy in Illinois This Winter

I get it. School just started. We're all enjoying that faux fall, before the heat ramps back up and the real deal finally takes over, so the last thing you want to hear about is snow. Unfortunately, that's exactly what we're covering today after the latest climate prediction from the NOAA and the National Weather Service.

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El Niño/La Niña, whichever one it is, it's sure to bring either extremely hot temperatures and storms, or ice-cold jet streams and precipitation of the icy sort. This time it's the latter, as La Niña stakes its claim over parts of Illinois, at least that's what the National Weather Service is predicting.

So what does that actually mean for us? In simple terms, La Niña is a natural climate pattern triggered by cooler-than-average water temperatures in the equatorial Pacific Ocean. That shift in the Pacific sends ripple effects through the atmosphere, tugging on the position of the jet stream. When La Niña is in charge, the jet stream tends to shift north, which usually favors colder, stormier conditions across the northern tier of the U.S. This time around, Illinois is right in that path as the stream dips to parts of Michigan, Indiana, Ohio, and Kentucky.

The Climate Prediction Center recently issued a La Niña Watch for the winter months, giving about a 50–60% chance that conditions will lock in this fall and stick around into early winter. Right now, forecasters expect this one to be weak, but even a weak La Niña can tilt the odds toward snowier conditions here in the Midwest.

Here’s the kicker: historical data shows a split personality. Strong La Niñas tend to dump heavy snow in the Northwest and Rockies but leave places like the Plains and Northeast drier. Weak La Niñas, on the other hand, are often snowier for the Midwest and the central U.S. I mean, remember a few years ago; polar vortex, and massive amounts of snow? That’s because weaker Pacific forcing gives other atmospheric players, like the Arctic Oscillation, a bigger role. When those bring in cold concurently, Illinois and the Tri-States end up with more chances to be on the snowy side of storms. This year, the predicted forecast seems to target most of Eastern Illinois.

Of course, a forecast for “more snow” doesn’t guarantee a whiteout winter. Snowfall depends not just on how much precipitation we get, but also on temperatures staying low enough during storm events. If we end up warmer than normal, those flakes can turn to slush or rain very fast. Still, the odds of Illinois seeing more than average snow are looking better this year compared to winters without La Niña.

Bottom line: if you live in Illinois, it’s worth digging the snow shovel out of the garage sooner rather than later. While last winter leaned more mild, this one could look a bit different, with La Niña giving us a better shot at those classic Midwest snow days (and all the kiddies cheered). Whether you’re pumped for snowmen or dreading the return of the shovel, this winter has the potential to keep things interesting.