The words “northwest flow” should be etched into your mind if you’ve been paying attention to the recent weather in the Rockies. This pattern brings moisture from the Pacific Ocean into British Columbia, then pushes it southeast toward Idaho, Montana, Wyoming and northern Colorado. The reason it’s called a “northwest flow” is because the storms move in from the northwest. Wind directions always describe where the weather is coming from.
Two storms will move through this northwest flow over the coming week.
The first storm will bring snow on New Years Eve and New Years Day with about 3-6" likely for Montana, Wyoming and northern Colorado. Some mountains might see more snow than this, but I feel that 3-6" is an average range for most areas.
The second storm will move through on Friday evening and Saturday. Accumulations will favor the same locations as the New Years storm, but might be a bit deeper with 4-8" falling on the mountains.
On Sunday and beyond, the forecast is impossible to pin down. The current weather pattern (northwest flow) is trying to change, and as usual during these periods of transition, the models just can’t get a handle on how things will evolve. So do your snow dance, wash the car and hope for a more west-to-east pattern that will bring snow back to Utah and other areas of the central and southern Rockies.
Joel Gratz is a Meteorologist and the creator of OpenSnow.com.