As can be seen in the sounding below, we have a whopper of an inversion over the Salt Lake Valley today. The surface temperature when the sounding was taken was -1.7ºC, but at upper levels, they were much warmer, including a +6.0ºC at 700 mb (about 10,000 feet).
Mountain dwellers, however, are going to experience an exceptionally warm January day. In fact, AT 8 AM MST THIS MORNING, IT WAS ALREADY 39ºF ON THE TOP OF MT. BALDY AT 11,000 FEET!
If you are skiing today, you will experience some of the warmest January temperatures on record.