1:30 PM, Wednesday, April 13, 2016
A long-duration period of wet weather (Friday-Monday) is likely to bring heavy snow to the mountains, and a mix a rain and wet snow in the lower foothills and plains.
The center of the storm system is slower than we thought a couple days ago, and likely to spin in place near or just south of the four corners region this weekend. In fact it may just slowly weaken in place and never move east of us. The impacts for the Front Range region may come as intervals of heavy precipitation separated by intervals of a relative lull, with heavier precipitation less likely by Monday.
The initial precipitation (Friday afternoon or evening) is likely to be rain and maybe some thunder at most elevations. There may even be a strong thunderstorm with hail and heavy rain, especially out on the high plains. Snow levels will probably work there way down to the lower foothills by Saturday morning. In the urban corridor, the changeover to snow will probably be very variable, but it’s too early to call right now.
Potential accumulations through the weekend:
Mountains and Palmer Divide above 7000 feet: 1-2 feet (and likely more in some local areas, especially above treeline)
Lower foothills (and Cheyenne): Highly variable from a few inches (after rain initially) to around a foot.
Colorado Springs, metro Denver, Boulder, Fort Collins: Mainly rain, but some heavy wet accumulation of a few inches in some local areas. Although a heavy wet snow is unlikely, it can’t be completely ruled out yet. Generally 1-2 inches of liquid is likely.
This storm is arriving almost 95 years to the day after the infamous Silver Lake snowstorm that produced 76 inches of snow in 24 hours on April 14-15, 1921, and 100 inches in 4 days. Silver Lake is in Boulder County at 10,240 feet elevation. Denver and Boulder had much less snow but saw a sloppy mess. Denver recorded 9 inches downtown. Boulder did not record the snow but reported 3.37″ of liquid and commented that the snow brought the city to a standstill.