Update - December 28, 2014

In the last post (click here) I discussed several things.  One was the opportunity for a little snow across the high plains (2 to 4 inches) for Friday into Saturday, but with a lot of uncertainty of the location.  Again, it's very difficult to impossible to pin point amounts or location when it's several days or more out.  In advance of the minor storm that produced the snow it warmed up considerably on Christmas Day with many locations reaching the 50s and 60s.  The snow that fell was concentrated in two locations across the plains. See the map below...(click for a larger version).

Attention now turns to a extreme Arctic outbreak, one that has been predicted for some time.  As of Sunday afternoon the leading edge was moving into the Dakotas.

Looking at the satellite, the polar jet stream was making a plunge into the U.S. and the cold has only one to go...SOUTH!  By Tuesday temperatures will have fallen into the single digits across most of the high plains (and perhaps below at a few spots).  Readings will stay primarily in the single digits during the day and with stiff north winds the wind chill index will be in the dangerous category.  There is even some evidence that temperatures may not get much above zero at a few spots.  Even with not much clearing Tuesday night it appears readings will fall below zero at many locations (see maps below). 

BTW, those temperatures you see on the above map?  That is NOT the wind chill index, it is the air temperature!

Snow will accompany this cold outbreak.  The liquid to snow ratio will be high so it should be a pretty fluffy snow.  I have high confidence of 1 to 4 inches across much of the high plains.  Details of course this far out are impossible so stay informed through the NWS website weather.gov/.