One of the joys or drawbacks of living along the Colorado Front Range (depending on one's point of view) is that snow may fall from early September through early June. Today's snowstorm is thus not unusual; indeed, following a mild winter and a nearly snowless March, we were due for snow in April and May (and certainly in need of its moisture).
The current storm is the product of a deep atmospheric trough that, yesterday, brought cold temperatures as far south as Northern Arizona and the mountains of New Mexico. As the trough pushed eastward across Colorado, it produced heavy snow in the mountains and ignited thunderstorms along the Front Range urban corridor last evening. By this morning, the rain had changed to snow as upslope winds developed on the backside of the storm system. Large, wet flakes pummeled our Littleton farm, leaving three inches of snow within a few hours and weighing down the shrubs and small trees (most of which are fully leafed-out).
As I write this post, the storm is centered over the southeast corner of Colorado (usually an ideal location to produce an upslope snowstorm in Metro Denver) and periods of heavy snow continue, occasionally mixed with rain. The temperature sits just above freezing and is forecast to remain stable through the night. Meanwhile, on the eastern edge of the system, severe thunderstorms and tornadoes are expected to rake the High Plains. See also: Upslope Slop in Colorado and Denver's Upslope Snowstorms.
