6:30 AM MST, Saturday, March 13, 2021
Since yesterday there is more forecast confidence that there won’t be a significant rain phase in the lower elevations, although there will probably be some rain and drizzle today. The heaviest period is expected to be snow later this afternoon through Sunday morning. At this time of year nighttime snowfall allows for better accumulation efficiency than during the day. Periods of accumulating snow are likely all the way into Sunday evening. We are now seeing the storm organize to the southwest and moisture streaming toward the Front Range from the east (lots of fog over the high plains). The short range models have moistened this storm a little since yesterday.
So I’ve bumped up some of the accumulation ranges a little. There are still some modeled solutions calling for widespread 5 feet in the mountains and 2-3 feet in the lower elevations, but I continue to believe that is unlikely.
20-36 inches: southeastern Wyoming, Colorado Front Range above 6500 feet for Larimer, Boulder, Gilpin, and Jefferson counties (lesser amounts as you move south toward the Pikes Peak region). I do expect some reports over 3 feet, most likely in Wyoming, or some small regions of either Larimer or Boulder Counties in Colorado.
18-24 inches: Fort Collins, Boulder, Broomfield, west and northwest Denver suburbs.
12-18 inches: most of Denver area, Longmont
4-9 inches: Colorado Springs (heaviest on north side)