September 22, 2016
Welcome to the first day of Autumn! Appropriately, a very moist system is racing up from the Baja (Leftovers of tropical storm Paine) and will take a direct path through Utah/Wyoming/Montana over the next 3 days. Heavy rain be falling at most elevations early with a shift to snow primarily above 7500 feet Friday/Saturday.
Specifics: Strong SW winds and warm temps will preclude a cold front racing down from Canada. 2-3 inches of moisture are likely in most of Utah, western Wyoming, and southern Montana through Saturday. Heavy snow will be falling after midnight into Friday over the Wasatch (Light accumulations at 7500 and most bases of the Cottonwoods, with 7-11 inches likely on the summits by early Saturday).
Peak snowfall will be Friday morning with the approach of the cold unstable air however “Lake Effect” snow bands will continue into Saturday morning. Can you believe we are talking “Lake Effect” in September? Heavy snow is also likely in SE Idaho near the Utah border above 8,000 feet. The Tetons edge out 3-7 inches above mid mountain and Big Sky in Montana could deliver 4-9 near the summit. Road impacts will be minimal due to the warm temperatures precluding the cold front (Top of Little Cottonwood near Alta could be interesting by late Friday).
Colorado remains on the Eastern edge of the bulk of moisture. Most snowfall ranges will be in the 2-4 inch range above 7500 feet Friday night into late Saturday. Higher amounts are possible above 10,000 feet.
– Powderchaser Steve