El Niño significantly impacting the Chicago area's winter weather outlook: NWS

from the warming of Pacific Ocean waters near the Americas. According to that latest outlook, a shift in the Pacific Jetstream could have significant impacts on the southern United States, pushing more rain than normal into those areas. “As we know from decades of observations, a very strong El Nino will likely bring a southward and eastward shift to the jet stream for the contiguous U.S., which tilts the odds toward stormier weather across the South,” said Ken Graham, director of NOAA’s the weather service,” in a statement. But what would an ongoing El Niño pattern mean for the Midwest, specifically the Chicago area? According to Illinois’ official climatologist, El Niño patterns typically result in warmer-than-normal winters in the Chicago area, along with drier-than-normal conditions. The newest winter weather outlook, which covers the meteorological winter beginning December 1 and ending Feb. 28, 2027, certainly jibes with the first portion of that, with the upper Midwest and the entire Chicago area firmly within the “above average” portion of the map in terms of winter temperatures. Still, forecasters and researchers caution that not all El Niño patterns are the same, and that an overall trend of above-average temperatures does not preclude cold snaps and winter snowstorms. As for precipitation, the forecast is far murkier in the Midwest. While confidence is growing that the south could see above-average precipitation during the winter months, the CPC says the Midwest, including the Chicago area, is still looking at roughly equal chances of above or below-average precipitation during the winter months. For context, the Chicago area typically sees around two inches of liquid precipitation per month during the winter months. For snowfall, the Chicago area typically sees an average of around seven inches of snow in December, then around 11 inches in both January and February, making them by far the snowiest months of the year. While the pattern of an El Niño typically comes with below-average precipitation, it would only take one or two major snowfalls to drastically alter the amount of snowfall the area will see during the winter, with forecast models still dialing in those amounts.