12:45 PM, Wednesday, May 17, 2017
The coming storm may be one for the record books! The storm is expected to move across southern Colorado tonight through Friday. The current track suggests the heaviest impacts are likely from the mountains and plains around Denver north to Cheyenne. Lesser impacts are likely from Colorado Springs southward. The area between Colorado Springs and south Denver will probably be on the edge of the intense part and should probably prepare for a heavy storm. The rest of this post will be referring to the likely heavy precipitation areas from Denver north to Cheyenne.
Rain should develop this evening and there may even be some areas that get a heavy thunderstorm. Rain should change to snow above 8500 feet this evening, and the snowline is likely to descend to the lower foothills by morning, with some heavy snow during the night. It is unlikely that there will be snow below 6000 feet, but there could be some heavy rain and an occasional mix with snow.
As the storm makes its close approach late Thursday through early Friday the temperatures should drop a few more degrees and that may be enough to bring the snowline down to the urban corridor. There is a lot of uncertainty for the lower elevations.
Amounts through Friday
1-4 inches of liquid (rain and melted snow) throughout the region
Above 7500 feet: 1.5 -3 feet of snow
6000-7500 feet: 6-20 inches of snow (very variable depending on elevation and convective snow bursts)
Below 6000 feet: most likely a trace-3 inches with some areas of 3-6 inches (we cannot rule out more widespread amounts of 6+ inches and will re-evaluate tomorrow)
**Some model guidance suggest there could be some localized high elevation areas of the Front Range with more than 4 inches of liquid and 3 feet of snow.
Difficult travel in the mountains and foothills
Although it’s less likely, if a 6-inch snowfall does occur in the lower elevations, that would result in serious tree damage and power disruptions. Be prepared for power outages and don’t park under trees.
A hard freeze is not likely in the lower elevations through Thursday afternoon. There is a good chance for temperatures near or below freezing Thursday night.
With clearing expected Friday night, areas of frosts and freezes are likely Saturday morning. If there is snow cover the chance for a freeze increases.