Noon MST, Friday, March 12, 2021

There is a lot more forecast guidance now available for the main snowy period from late Saturday afternoon to Sunday afternoon, including the short range, high resolution weather models. Although there is a still a large range of snowfall possibility, a majority of the guidance does point to less precipitation and slightly denser snow than the previous outlook. It still looks like the heaviest amounts will be in southeastern Wyoming, fairly minor amounts in Colorado Springs, and a transition to the lesser amounts somewhere south of Denver. A small portion of the guidance suggests rain in the urban corridor through Saturday evening, but I still think it is likely that most precipitation will be snow when the heavier period begins late Saturday afternoon.

Updated most likely accumulation

20-30 inches: southeastern Wyoming (some 36-inch amounts on east-facing slopes).

18-28 inches: east slopes of Colorado mountains above 6500 feet and north of I-70.

10-20 inches: east slopes above 6500 feet south of I-70 and north of Pikes Peak

12-20 inches: Fort Collins, Boulder, Broomfield, and northwest Denver suburbs

8-15 inches: most of metro Denver, Longmont

less than 6 inches: Colorado Springs

Outlier possibilities on the high end

The very big amounts that have been talked about the last few days (and die hard on social media), are still possible, but the chances appear to be around 10%.

Outlier possibility on the low end

Similarly on the low end is an unlikely but still plausible scenario where the numbers above can be cut in half. That’s about a 10% chance in Wyoming and maybe 20% in Colorado.