Brrrrrrr, it's cold out here!

In the wake of the 2 systems that have passed through the past 48 hours we will be getting some very cold, arctic air filtering down into the region.  This cold air has been positioned over much of the central United States after it moved down from Canada early in the week.  It has brought some very cold single digit highs, highs in the 20s and even Phoenix, AZ experienced a high of 53 on Monday, a temperature very unlikely for this time of year.  These will be the coldest temperatures we've felt in quite some time; with high temperatures only reaching the lower 30s and lows in the teens.  One positive of these colder temperatures is that it will bring some sunshine back for the weekend.  How long will these temperatures last you might be asking?  Temperatures will return to the 40s again early next week and it has also been forecasted that the average December 2011 temperature will be above normal.  One of the reasons for this is the position of the jet stream.  The jet stream has not dug too far south below us yet and it isn't expected to either as there is no blocking system set up and there seems to be no drastic pattern change in sight to bring us significantly colder temperatures.

Here's a really cool image showing the temperature changes in the US over the past 24 hours or so:

Image from: The Weather Channel (www.weather.com)