There are two components to the incoming storm. A warm plume of Pacific moisture and a robust cold front. The timing of the two coming together has been quite complex. It now appears that far SW Montana and Western Montana along the Idaho border will see the heaviest snow, with storm totals of 6 - 12" through Mon. High-pressure returns Tues - Weds, with unsettled skies Thurs into next weekend.

A storm will arrive early on Sunday morning, leading to off and on snow showers throughout Sunday and Sunday night with light to moderate totals expected. Snow will trend drier/more powdery over time. Winds will be strong on Sunday and Monday AM will offer the best skiing conditions. After a break on Tue-Wed, snow chances are expected Dec 12-15 but with low confidence in the details.

Very warm temperatures have overspread the Cascades, and rain is falling in many areas. Colder air will overspread the PNW by later Saturday, bringing moderate to heavy snowfall to many places through Sunday. Leftovers will move into the Panhandle of Idaho and northern Montana before weakening over the Rockies. Moisture will continue mid to late next week, favoring northern areas of the west.

The West will finally see a storm this weekend following an extended dry spell. The storm will favor the interior of Canada for the highest totals, while the Washington Cascades and BC Coast Range will start as rain before changing to snow. Lighter snow will fall in the U.S. Rockies. New England will see more snow this weekend with a combination of rain, snow, and mixed precipitation next week.

Thanks for reading this summer! For the rest of this week, a cold front moving across the Central Rockies will bring showers & t-storms to WY, CO, & NM Wed-Thu while the West Coast states will see a late-season heat wave. Next week, isolated to scattered showers & t-storms develop across the West with continued mild temps. Heading into mid-month, the PNW will trend wetter and cooler.