December 2013 will go down in the record books as the coldest December in years and one of the coldest on record. As of yesterday, the month has a mean temperature of 11.4 degrees??7.2 degrees below the long-term average. The average mean for the entire month is 18.5 degrees.
The coldest December on record was 1983 with a bone-chilling mean of 8.7 degrees. Six years later, December 1989 came in at 9.2 degrees. Since then, Decembers have been generally quite mild. The last cold December was five years ago. In 2008, the mean temperature for the month was 13.3 degrees. Back in 2000, the mean wound up at 12.1 degrees.
Today with the high barely getting to zero and the low well below the zero mark, the day will come in at least 15 degrees below average. This will likely knock the mean temperature for the month down below 11 degrees. It will not challenge the cold of the 80s, but the figure is impressive nonetheless.
January 2014 will get out of the cold gate quickly. There will be a brief warm up on Friday into Saturday. Then, it appears that the ??mother lode?? of cold air will be taking aim on Upper Michigan early next week. An arctic upper low over far northern Canada this morning will dive southward. It is this disturbance that will park itself close by early next week (Image 1 above). If this scenario unfolds as forecast, the coldest air over the Northern Hemisphere will flow into Upper Michigan on strong northwesterly winds next Monday and Tuesday.