Tonight and into tomorrow, January 18, 2022, the Colorado region will experience an array of winter weather from freezing fog, drizzle, snow, sleet, graupel and sleet/ice pellets. This is in part due to the above average temperatures from previous days combined with a slow moving northwesterly disturbance resulting in weak low-level mixing. This weak mixing will effectively trap pockets of warmer air between layers of the atmosphere which limits snow production overall. However, this enhances other interesting types of precipitation such as sleet and graupel, which are similar to hail, just very small and soft more like popcorn.
Overnight tonight and into daybreak tomorrow, any and all precipitation should fall as snow, mainly in the foothills as areas along the plains will stay relatively dry through this evening. Isolated areas of patchy freezing fog could be possible on the plains early tomorrow morning with off an on freezing drizzle/sleet/snow during the morning and into tomorrow afternoon.
Here is a list provided by the National Weather Service on the different types of precipitation:
Also a few Winter Weather Definitions: