As a major winter storm barrels toward the metro area, there’s a clearer picture of just how much snow Denver will receive.
Scattered rain and snow showers are expected to start Thursday afternoon and continue into the evening. Most of the activity will be over the mountains and foothills, where up to 3 inches of snow will be possible tonight. Some showers may move off the hills and onto the plains.
Denver’s highest chance for precipitation is after 1 p.m. today amid partly sunny skies and a high of 45 degrees, according to the National Weather Service. Thursday night has a slight chance of snow around midnight when the temperature is expected to drop to 30 degrees.
Light precipitation is expected during the day on Friday with low impacts. Parts of the northern foothills could see a couple of inches of snow. It will be 43 degrees in Denver with not much accumulation.
A winter storm warning goes into effect Friday night and lasts until Sunday night as the powerful snowmaking system finally begins dumping powder. It impacts Fort Collins, Boulder and the western suburbs of Denver, Denver, Castle Rock, and Greeley.
“Heavy snow is possible. Total snow accumulations of 15 to 25 inches is possible. Accumulations up to 30 inches possible near Boulder and Fort Collins. Winds could gust as high as 35 mph,” the warning from the NWS reads.
Updated storm total snow map! 15-25″ expected across urban corridor with up to 30″ in Boulder and Fort Collins. 2 to 4 feet of snow in the foothills. Lower amounts west of Continental Divide and east of DIA. #COwx pic.twitter.com/ykTuxhsuiC
— NWS Boulder (@NWSBoulder) March 11, 2021
“A cut-off trough which is currently spinning just off the California coast will move slowly to the east today and tomorrow winding up just south of Las Vegas tomorrow afternoon,” the NWS wrote. “The trough will continue to move eastward Friday, eventually winding up almost directly over the Four Corners by Saturday morning. This period of the storm has quite a bit of uncertainty because of the convective potential that exists.”
Snowfall amounts across the urban corridor will be between one and two feet, with the foothills seeing up to four feet. Accumulation will be lighter west of the Continental Divide and east of Denver International Airport. Travel across the urban corridor and foothills may become impossible Saturday through much of Sunday.
“An elevated layer of instability will end up being across eastern Colorado late Friday night into the day on Saturday. A few elevated thunderstorms appear likely to develop over southeastern Colorado and will track northward across our forecast area,” the NWS said. “The area east of DIA is the biggest question mark in terms of precipitation type as warm surface/low-level temperatures should lead to very little snow accumulation during this time. However, if for some reason snow does fall and stick, it could accumulate rapidly.”
Friday night will drop down to 30 degrees, and Saturday will jump only to 34 degrees during the middle of the storm.
“By late Saturday and into Saturday night, the cut-off trough will enter southern Colorado. The exact positioning of the trough will be crucial for determining snowfall amounts across our forecast area,” the NWS explained. “This is because the trough position will determine the position of the mechanism that will create the heaviest snowfall bands and totals from this storm. A track that is farther to the south would mean higher amounts for our area with a farther north track meaning less snow.”
Saturday night’s temperature will be 29 degrees, with Sunday reaching a high of 33 degrees.
The National Weather Service says the foothills could see snowfall rates of nearly three inches per hour on Saturday. Boulder and Fort Collins could see tow inches per hour during the same period.
“The system will become vertically stacked on Sunday as it almost becomes stationary over far southeastern Colorado or western Kansas. This will weaken the system and snowfall rates are expected to decrease substantially,” the NWS explains. “The chance for snow will linger into Sunday night and Monday morning before ending around midday Monday. Winds should be strongest during the day Sunday, with blowing and drifting snow possible. Gusts could reach up to 45 mph across the plains, which may create near-blizzard conditions at times.”