CBS2 Boise – Rain is expected Sunday night into early Monday morning as the next burst of moisture moves through the state. Snow depth will be between 5,500 and 6,000 feet. This means it will snow in the upper half of our ski areas. However, many mountain valleys will see a mix of rain and snow. The window remains wide open, allowing one surge of moisture after another to spread across the region. The only thing these storms lack is cold air. As a result, the periods of showers we will see will be valley rain and mountain snow. Highs this week will remain in the 40s. The moisture transported in this way consists largely of subtropical air. These atmospheric rivers will bring lots of very mild air through the end of the week.

So far this year our temperatures have been very mild. That’s because we didn’t see a cold air outbreak. This means we always take advantage of the mild air from the Central Pacific. The jet stream was active, but the orientation was west to east. If you want cold air and valley snow and a white Christmas, the orientation needs to be changed to a northwest-southeast flow. The computer models say that won’t happen this week. That’s why temperatures at this time of year remain 7-10 degrees above normal. Sometimes weather conditions can get stuck in the rut. But at least we see precipitation and mountain snow. This is certainly better than high pressure and inversion.