Patchy freezing Fog to start

Plenty of cold air is trapped in the valley creating the freezing fog you may run across ahead of mid-morning.  Low clouds first, then cold sunshine and falling short of freezing, around 28 in Idaho Falls. N 5-10 and wind chills at 0. After clearing this afternoon, we'll have single digit lows tonight around 9 with 5-10 mph winds. That makes wind chills below zero.We'll continue in this cycle of cold dry trapped air into Tuesday with patchy freezing fog tonight and into the early morning. High 29. Cold again Tuesday night with single digit lows, around 10.  The warm up above freezing comes Wednesday afternoon - around 36 in the valley. 
As we look ahead, moisture and snow are back in the forecast by Saturday with a 50% chance of snow. 
Jeff Roper, First Alert Weather