Summary: According to NOAA, La Niña has arrived and there is a 65-75 percent chance that it will persist through this winter before fading sometime in the spring. We talked about La Niña in an earlier post here. Illinois has an increased chance of being wetter than normal for this winter and spring with an increased chance of being warmer than normal in spring in central and southern Illinois.
November So Far
November this year is starting out much colder than last year. The statewide average temperature for November 1-16 of this year was 41.7 degrees, 1.4 degrees below normal. Most stations have reported lows below freezing at some point in November and many sites in northern Illinois reached down into the low teens. By contrast, the statewide average temperature for November 1-16 of last year, was 52.3 degrees, 8.1 degrees above normal. And stations in northern Illinois had only reached down into the mid-20s by this point.
The outlook for December is not very interesting for Illinois. We have equal chances (EC) of above-, below-, and near-normal temperatures and precipitation. In other words, there are no clear climate signals to indicate any unusual conditions during December. Wetter than normal conditions are favored in states to the north of us and drier than normal conditions are favored in states to the south of us. Click on the maps to enlarge.
For the winter months of December, January, and February, wetter than normal conditions are favored for Illinois, as well as the northern and Great Lakes states. Neither warmer nor colder than normal conditions are favored in Illinois. However, many states to the south of Illinois are favored to be warmer than normal. Northern tier states from Washington to Minnesota are favored to be colder than normal. Hmm, colder and wetter than normal conditions expected in the Dakotas and MN this winter – sure sounds like a recipe for more snow to me.
For the spring months of March, April, and May, wetter than normal conditions are favored for all of Illinois. Warmer than normal conditions are favored in central and southern Illinois. Meanwhile, neither warmer nor colder than normal conditions are favored in northern Illinois (labeled EC on the map).