Hot air rises, and cold air sinks. Denver, as you know, is in the bottom of a bowl. When it gets really cold in Denver, the air sinks down into the bowl, and really doesn't have a lot of energy to get out. Expect the cold temperatures to last longer than people want it to.
The temperature inversion happens with fronts that move North to South. These are usually called Alberta Clippers. For storms moving in from the NW the storm must come over the continental divide, 13,000-14,000ft around here. The wind from the front being squeezed over the divide can be over 100mph, but the NW wind coming down over the divide warms up (PV=nRT). Sometimes we warm up to 20F!