12:35 PM MST, Thursday, February 28, 2019
Cold front #1 late Friday will start the colder trend. Cold front #2 on Saturday afternoon and early evening will bring in a bitterly cold arctic air mass. Snow in the eastern foothills and plains could occur at any time from Friday evening through Sunday morning, but it appears that late Saturday may bring the best chance for significant accumulations.
Eastern foothills and plains, including the urban corridor:
Friday evening and overnight will bring the first chance, but this is looking fairly minor and spotty. There may be an east-west band that can produce a couple of inches, but if that happens it will most likely be north of the Denver-Boulder area.
Saturday into early Sunday is forecast to bring a better chance of significant snow, with 4-8 inches from the Palmer Divide northward (probably a little less in Colorado Springs). Snow will likely be underway in southeastern Wyoming during the morning Saturday, and then spread north to south along the Colorado Front Range Saturday afternoon. Some east-west bands (aligned with the jet stream) may propagate north-to-south resulting in occasional heavy snowfall rates. Although the heaviest snow may end up near the foothills, the chance for blowing & drifting snow increases as you go east.
The Pacific moisture helping to feed the Front Range snow will bring some heavy snow to the mountains and west-facing slopes first, especially on Friday. Over a foot is likely in parts of Colorado’s northern and central mountains, and Wyoming’s Medicine Bow range.
Friday should start mild but colder air should be working it’s way in from the northeast during the afternoon. Saturday may still reach the 30s along the Colorado Front Range urban corridor but fall during the afternoon with the arctic front. Then, temperatures are likely to tumble into the singles digits Saturday night, only get to the teens Sunday, and if skies clear, there may be widespread readings near or a little below zero on Monday morning.
The record low maximum temperature for Sunday is 15 in Boulder and 14 in Denver.
The record low for Monday morning is -1 in Boulder and -3 in Denver.
All of the above records were set in 1978 and could be within reach.