Deep moist southerly flow will continue bringing intermittent rain to southwestern Idaho and southeastern Oregon through the holiday, with a significant weather pattern change expected this weekend that will bring mountain snow and valley fog conditions.
Tonight Through Holiday: Warm Rain Persists
The strong surface pressure gradient responsible for recent windy conditions will relax tonight, allowing winds to subside this evening. However, the moist flow from an upper-level trough and storm system will continue bringing intermittent periods of rain to the area through the holiday.
Even mountain areas will see rain rather than snow, as snow levels remain above 6,500 feet through the holiday. Temperatures will cool a few degrees in the rain but will still run about 15 degrees above normal for the holiday.
The unseasonably warm and wet pattern represents a stark departure from typical late December weather, with rain dominating instead of the snow typically expected this time of year.
Friday: Transition Begins
Temperatures will cool by another 5 to 10 degrees Friday as the main upper-level trough and storm system move through the area. This cooling will bring snow levels down to the 4,000 to 5,000-foot range, finally allowing for snow accumulations above these elevations…