The Climate Prediction Center issued an update on the outlook for the upcoming winter, and there's a decent chance that La Niña conditions in the Pacific may affect our winter weather here at home.
For reference, La Niña conditions occur when the ocean waters near the Equator along South America are colder than average during the winter. This results in the trade winds pushing colder water closer to that end of the Pacific. The colder waters, in turn, divert or change the general pattern of the polar jet stream over North America. In short- the colder waters change the jet stream, which adds to what we get this winter.
La Niña winters generally bring wetter than average conditions to Illinois during the winter. This isn't a guarantee that we will get a ton of snow; it all depends on the temperatures as well as the exact track of the jet stream across the area. However, conditions are usually a little wetter with La Niña locally, so snow amounts may be higher, especially compared to the much drier and warmer winters lately that have cut down on our snow amounts. Rockford gets 29.2" of snow during a typical winter.
La Niña is the opposite side of El Niño, which we have seen a little more often lately. The two generally cycle back and forth, so its our turn for La Niña this time around. Across the country, the southern half of the U.S. is generally drier than average, with the Gulf States and the southern East Coast drier and warmer than average. The Pacific Northwest also ends up wetter than average, and areas like the Dakotas and Montana getting more bone-chilling cold than usual.