The cold front is now entering Colorado with light snow falling at most ski areas currently along I-70. Snow intensity picks up later Tuesday before ending on Wednesday morning. The Wasatch is gambling on some lake effect today where 8-14 inches are likely for the Cottonwoods (Wildcard). Colorado snow totals will be widely variable with some surprises-both low or high from this storm. Temps at mountain top locations are already in the single digits in many areas and will drop below 0 tonight.
Light snow is falling over most of the I-70 corridor currently, with moderate amounts near Denver and areas East.
In looking at various models this morning my confidence is high for significant snowfall along the eastern foothills near Denver, Boulder, Rocky Mountain National Park, and areas south and east of Denver on I-25 (Eastern plains south of Denver). These areas could easily see 9-15 inches or more by Wednesday morning. Most of the deepest amounts will fall east of most ski areas.
When looking at the short term resolution HRR and GFS this morning all agree that significant snow is likely south of Summit County towards Leadville, Ski Cooper or even Monarch. The winds are veering N or NE as the day progresses in the Front Range (Good for the eastern portions of the State and Foothills). On the western side of the State winds but remain SW initially before veering W or NW late Tuesday. The NW winds on the western side of the State will ramp up snowfall tonight for the western mountains. Moisture is not significant but the snow ratios are 15 or 20:1. This makes for a tricky forecast (Wind directions and exact areas with the highest precipitation will dictate the winners). This system is not overly moist but has good cold air orographics especially on the eastern side of the Divide (Upslope).
My chase forecast is going with 5-11 inches along the Continental Divide (Loveland, Winter Park), 4-9 for Summit County, and a few surprises possible for Steamboat. The models show higher amounts on Rabbit Ears Pass (2 inches fell in the past few hours). Areas north of I-70 towards Rocky Mountain National Park or even Berthoud Pass may come in with higher amounts.
Further west in Colorado it's possible that Beaver Creek, Vail score some surprises in the 5-9 inch range. Aspen will see slightly less. Wind direction stays more W or NW which is good for those areas.
I would closely watch Monarch or Ski Cooper as the models are advertising some decent totals south of Summit into Lake and Chaffee Counties. Areas further south in the San Juan range (Telluride) will see some lighter amounts (2-5).
Bottom Line: Moderate event for Summit County. Decent event for areas along or north of the Divide. Surprises possible for Steamboat, Beaver Creek or Vail (Wildcards). Ski Cooper is worth watching as well as Monarch with very high moisture totals in those areas (Monarch does best with a West-NW wind so the NE upslope can sometimes score big totals in Salida with much less on the pass).
Most of the Wasatch will grab 4-8 inches today (Northern areas see less than the southern counterparts). Lake effect is very possible initially impacting the Cottonwoods late AM Tuesday (W-NW flow). This could quickly accumulate with Little Cottonwood favored in the 9-15 inch range by 5 PM. Winds shift more N or NE later Tuesday pushing higher amounts east of Salt Lake (Lake Effect in the Tooele Valley).
Bottom Line: Moderate event for most ski areas. Wildcard Lake effect may produce significant amounts in the Cottonwoods.
A weak system will usher in some light or moderate snow late this week for most of Montana and perhaps areas in Wyoming Thursday and Friday (central Montana and Wyoming might be your best picks). The amounts should stay on the light side.
High pressure builds into the west after these departing systems with some signals of another system possible around November 4th
Below: Some signal of a weak or moderate trough for the northern Rockies on November 3-4 timeframe