A look at the Wed/Thu storm system (snow for the mountains)

04/28/25 8pm: Heads up: seeing an interesting setup for the Wed/Thu storm as models continue to show a fairly potent little short-wave and cold-front. Still some uncertainty in overall strength and how cold it will get but at at the minimum looking like an early May snow-storm for the mountains and some cold rain, maybe a little bit of snow for Den/Bou.

Models show the left exit region of the jet-stream moving across northern CO Wed night into Thu am...this combined with a larger trough and low to our west will pull in some colder air from the north and some northeasterly upslope on the front-range. Also look like some good surface convergence over the Front Range mountains and foothills above 8500ft, that area will be favored for heaviest snow (I circled the area with biggest impacts on the first image below).

For the north-central mountains including Summit, Grand, ClearCreek, western Boulder/Larimer counties moderate snow expected from about 6pm Wed through 9pm Thu, heaviest Thu morning. Generally 2-8" of new snow for some of the ski areas and mountains passes, favoring areas along/east of the Cont. Divide: Front Range mountains, including Loveland, Berthoud, Jones passes, Winter Park, IPW, RMNP and Cameron Pass (maybe up to 12" in some of those areas).

For Den/Bou, foothills and the northern front-range, the main rain/snow event will be from 9pm Wed to 12pm Thu. Initially looks like all rain below 8kft on Wed night, then by 6am Thu snow-line may drop to around 5300ft so some snow possible on grassy surfaces mostly in the western and southern suburbs (above 5400ft): Trace-2" possible for urban areas. Foothills west of Den/Bou can expect 1-5" in spots (best chances above 8k ft).

The cold-front will also move all the way down the front-range on Thu bringing rain/snow to areas like Colorado Springs, Pueblo and Trinidad (by Thu evening).

And prior to all of this a round of rain/snow showers expected for both the mountains and front-range tomorrow afternoon / evening after 3pm into early Wed (some light snow accum in the mountains as well). I'll have more on that tomorrow am.

First image shows forecast total snowfall from now through 6am Fri from latest NWS Blend of Models, take with grain of salt but I circled where biggest impacts are expected. Image 2 show equivalent but for total liquid precip through 6am Fri. Image 3 shows forecast total snowfall from latest GFS through 6am Fri, take with big grain of salt but you can see some stronger signals (ECMWF shows less). Image 4 shows the setup at the surface (precip-type, mslp and thickness) from latest GFS valid 12am Thu.