What a pattern we have been stuck in… 15 of the first 21 days of December we have seen at least a trace of snow at the airport and temperatures averaging almost 8 degrees below average and unfortunately it looks to continue right into 2014. Several more Alberta Clippers are expected to push southward out of Canada and keep the region entrenched in a cold and unsettled pattern for at least another week. The Climate Prediction Center is seeing the same scenario as they issued their 14 day forecast showing continued cold conditions for Minnesota, Wisconsin, and Michigan. The first image below is their significant weather forecast for the December 23 to 27 time period and the second image is the same forecast for the 28th through January 3th.
You can see that they continue to predict periods of well below average temperatures specifically from the 23rd-24th and the 26th-27th, plus again from the 28th through the 3rd of January. If this forecast rings true, this could be one of the top 10 coldest Decembers on record for the state and coldest in some 30 years… but those numbers have yet to be worked out.
So how do we know this pattern will continue?? Well, we don't know for sure, but we have very good indications. The following images show the forecast vorticity. Vorticity is basically just a fancy word for spin. If there is spin, then there is likely a low pressure nearby because that essentially is what a pressure low is… they are eddies in the overall flow of the atmosphere.
Notice that you see a similar situation in all of these images… bright colors showing up over the state indicating some spin, or as we know it, an area of low pressure. As they travel southeast, they bring cold Canadian air with them and continue to reinforce our chilly conditions that we have been experiencing for more than 2 weeks. Each low will provide a shot at some more light snow, with a more significant wave possible late next weekend. As you can see in the final Sunday Night image, there are 2 different lows across the country which could provide fuel for another large storm somewhere in the country.