Recently, the weather has been more appreciable of December weather, with temperatures sometimes unable to get out of the 20’s and a couple instances of snow. Over the past two weeks, two main concerns have been brought to meteorologists in Chicago:

1. The weather pattern that was originally warmer with a ridge of warm air in place has taken a significant turn. Now, a trough of cold air is locked over the eastern part of the Contiguous United States (CONUS) which has been providing extreme temperatures as low as 20 degrees below average. The trough of cold air over the eastern CONUS is a direct response of the ridge of warm and dry air over the western part of the country, responsible for the damaging California Wildfires.
2. A clipper system that recently impacted Chicago on Nov. 9 was responsible for the local three inches of snow. Since we don’t typically see our first measurable snow (0.1 in) until Nov. 16, these two to three inches come as an early surprise. This is especially surprising given that we have not seen more than one inch of snow before Nov. 10 since 1989. On average, the first snowfall of an inch or more is on Dec. 2, so we are ahead of schedule. This early snowfall may be signaling a potentially more severe winter compared to the last few years.

For people wishing for milder weather, it will return to the region by the 17th. This weather won’t be very mild, but rather will nudge us near our average temperatures, currently in the low 40’s. Beyond the 24th and into December, the Climate Forecast System, CFSv2, predicts another series of arctic blasts, likely keeping our high temperatures in the 20’s. The Thanksgiving forecast calls for temperatures in the lower 40’s with partly cloudy skies. Snow is not likely, but I wouldn’t be surprised to see some flurry action.