The cold northerly flow continues across Star Valley. Fast moving disturbances embedded in the flow will bring periods of clouds and light snow. One such system brought 1-2 inches Saturday night and another one is scheduled to drop southward and bring no more than an inch or two on Sunday.
Of more importance, this next system is going to be followed by very cold air, originating over Northwest Canada. Although this is still not a true Arctic air mass as temperatures this morning over the Yukon are generally above zero, the ingredients are coming into place to drop temperatures over Star Valley Sunday night to well below zero. Skies should clear in the wake of Sundays system and the combination of light winds and the cold air aloft will lead to ideal conditions for a very cold night.
It now appears that 10-15 below zero will be common in the valley locations by sunrise Monday, with the coldest locations dropping to 20 below or lower. The only areas that may be spared the extreme cold would be the communities above the valley floor such as Star Valley Ranch where it could go no lower than about 5 below.
Gradual moderation in temperatures will occur into the middle of the coming week, however they are expected to remain well below normal for the first week in December. The pattern remains unfavorable for a significant snowstorm in Star Valley, probably through the coming week.