Cold weather is here: will it last?

The cold weather did indeed arrive--the high today in Madison was only 20 after a morning low of 10, 20 degrees below normal. Milwaukee was not much warmer at 22 and 15. Temperatures in Madison have been 20 degrees above normal recently in both September and October, but it's been since last winter that we've seen 20 degrees below average. It looks like we'll see a bit of a warmup in the next few days, with 40s possible on both Sunday and Monday, which will probably feel very comfortable after the 20 degrees today. However, the eastern-US upper level trough that is causing our cold weather now looks like it may return by Tuesday and Wednesday, with another couple days of very cold weather possible by then. After that, the exact location of the boundary between warm weather in the west and very cold weather in the east will determine whether we're going to be warm, cool, or frigid. It looks like a good bet that in the 7-14 day time frame Colorado will be warmer than average and Maryland colder, but for Wisconsin it's still uncertain.

Risk of cold weather in coming week or two increasing

A very cold arctic airmass has been building in Alaska and far northern Canada over the last week. Over the first eight days of November, Fairbanks, Alaska has had an average high of 0 and average low of -13, fifteen degrees below normal for the beginning of November. So far, this very cold air has been held up by the jet stream over the far north, but that may change over the next week or two. The computer models have a difficult time forecasting weather patterns this time of year, especially the track of storm systems and the movement of very cold arctic air masses, and so a few minor changes in the flow could result in major changes to the forecast in the day five to day ten period. Depending on the evolution of the jet stream, Wisconsin could see two or more days next week with high temperatures in the 20s and a chance of snow, or the cold air could get held up and the weather could remain relatively mild. As of today, the colder scenario appears more likely.