Winter weather creating rainy Sunday for lowlands and snow in mountain areas

A wintry weather pattern has settled over Eastern Idaho and Western Wyoming this Sunday, bringing rain to our valley and plains and snow to the higher elevations. Abnormal temperatures on this Winter solstice mean we are still experiencing a warmer creep into the winter season.

Heavy mountain snow is expected from this early Sunday through Monday morning, especially in the Central Mountains. A winter storm warning from 2 am Sunday to 11 am Monday for Sawtooth/Stanley Basin, Sun Valley Region, and Galena Summit. A winter weather advisory will also be in effect from 2 am Sunday to 11 am Monday for the Island Park/Centennial Mountains area, the Big Hole Mountains, and Emigration Summit.

There will be ample moisture across the eastern Magic Valley and Snake River Plain, but temperatures remain mild, with snow levels for this area around 6,000 ft early Sunday AM and rising throughout the day. Total precipitation here will range from 0.50" to 1.00" for many and will generally fall as all rain. Some higher elevations will exceed 1.50" of liquid equivalent precipitation. Snowfall will increase rapidly with elevation, with the primary impacts for travelers crossing mountain passes.

By Sunday afternoon and early evening, most of Eastern Idaho and Western Wyoming will experience rain replacing earlier precipitation. Temperatures are expected to rise into the low 40s, with steady rain at times, and a 100% chance of precipitation during the day, continuing into Sunday night and early Monday morning. Wind gusts will increase Sunday night into Monday, but remain below advisory levels. Gusts will range from 20 to 30 mph for most. Rain continues through Monday, with highs near 46°.

While snow levels remain high, mountain regions will continue to accumulate snow, whereas valleys will remain mostly rainy. Looking ahead to Christmas Eve, Christmas Day, and the following days, the forecast remains wet. With temperatures significantly above normal, a white Christmas in lower elevations is unlikely. Any snow on Christmas morning will probably fall early and melt quickly as warmer air settles in.

Checking our region's forecast for Christmas Eve, Christmas Day, and the day after, it remains wet. With well-above-normal temperatures, the chances of a white Christmas in lower elevations are slim. Any snow that falls on Christmas morning would likely fall early and melt quickly as warmer air moves in.