The prospects for a white Christmas for most of the Salt Lake Valley are going to go down to the wire. We had a brief flirtation with dendrites this morning, but alas, it left only a dusting on the grass.
That means we're going to need a Christmas Eve miracle, which is likely to happen. The models bring a multi-part storm into the state starting tonight and continuing through early morning on Christmas. The first part of this storm is fairly warm. At midnight tonight, we are moist southwesterly flow with a 700-mb temperature of almost -6C. That usually means snow levels will be near bench level.
Snow levels drop, however, overnight and a second colder system moves in during the day on Christmas Eve.
Given the higher snow levels during the first part of the storm, accumulations are likely to be heaviest on the upper-elevation benches, but even the valley floor should should get a coating during the day tomorrow. Keep your fingers crossed.
With regards to the mountains, this storm is going to spread the Christmas cheer. Everyone is going to get some snow out of this given the gradual transition from southwesterly to northwesterly flow. In addition, this is the type of storm that lays down the Greatest Snow on Earth. It will start out warm, laying down some higher density snow, then transition to cold, so it finishes with some cold smoke. Our algorithms have it starting out at around 8% water content tonight, decreasing to 4% on Monday morning. That's ideal snow for deep powder skiing. Merry Christmas!