A look at forecast details for first part of the storm system from Sun afternoon through Tue morning

05/04/25 10:15am: Hi, lets take a look at some details for the first part of the storm system through Tue am, since we are in range of the high-res models now (at least for the first part). Overall forecast remains on track with a few changes. Still some uncertainty in how far north the main upper-level low sets up on Tue into Wed and that will ultimately determine rain and snow amounts over northern CO.

This is looking like a big event for southern CO / southern front-range and still should be pretty big as well for the northern front-range near Den/Bou and the adjacent front-range mountains and foothills (but just higher uncertainty there).

One thing that is a bit more clear is that from this afternoon through Tue am, the focus for heaviest rain/snow will be over southern CO (and generally along/south of I-70 in the mountains).

The main heavy rain event (and snow above 8k ft) for Den/Bou and the northern front-range (and north-central mountains) now appears to be from 12pm Tue to 12pm Wed...prior to this some on/off rounds of rain (and snow up high)...but likely not that much by Tue am....with big amounts by Wed am.

For today, over southern CO including San Juans, parts of the Elks, Collegiate Range, SLV, Sangres, etc (areas from Leadville south), rounds for thunderstorms and rain and snow showers (snow-level above 10k ft) from 2pm today through 2am Tue. High-res models show 10-20" of snow for the higher terrain above 9500ft (San Juans, Collegiates (southern Sawatch), Sangres will be favored initially, also some in the Elks as well an)

For the north-central mountains / I-70 mountain corridor (and the front-range mountains), on/off rounds of rain and snow from about 2pm today through 11pm Mon (with a big break Mon am: 3am-11am). Heavier rain/snow by Mon night into Tue. But generally looking at initially 2-6" of new snow by Tue am for some ski area, higher terrain and mountain passes (above 9k ft), favoring areas closer to Hoosier Pass to A-Basin (areas south and east of Summit Co.), less snow from Berthoud north with this first round.

For Den/Bou and the front-range some isolated, high-based storms mostly in the foothills west / southwest of Denver (and from the Palmer Divide south) from 6pm-11pm today (most areas stay dry). Then a round of rain showers and weak thunderstorms likely from about 12pm-10pm Mon....again best coverage expected south and west of Denver.... Springs to Pueblo will likely get heavy rain on Mon afternoon (with heavy snow for Pikes Peak).

Then the heavier rain moves back towards the front-range on Tue...starting in southeast CO and filling in north.

For Den/Bou foothills and the northern front-range the main rain event will be from 12pm Tue to 12pm Wed, snow level will remain above about 8k ft. Stil looking at 1-2" of liquid precip. Foothills can expect 4-10"+ of new snow.

North-central mountains and especially Front Range mountains will also get some heavy snow (above 8k ft) from a 9am Tue through 12pm Wed, with snow showers lingering into early Thu am: Look like an additional 6-14"of new snow favoring areas along/east of the Cont. Divide (A-Basin, Loveland, Berthoud, Winter Park, IPW, RMNP and Cameron Pass areas will be favored for second half of event), so totals of 8-18" in spots by Thu am.

More rain/snow for southern CO, southern front-range, San Juans, Sangres, etc especially from 6pm Tue through 12am Thu....additional 6-12"+ for the higher terrain above 9k ft down there (so that will bring snow totals into the 16-24" range including the Sun-Tue wave).

The storm clears out by Thu am. I see Tue pm, Wed all day and Thu am as the best powder days (Mauary will be in effect lol).

That is all for now. Its a complex and big storm system with two parts so we will see how this all goes, I'm sure some details will change.

First image below shows forecast radar over the next 48hrs (from 6am this morning through 6am Tue) from latest HRRR, just the first part of the event. Images 2 and 3 shows forecast total liquid precip and snowfall through just 6am Tue (first part) from latest HRRR. Image 4 shows forecast total liquid precip from now through 6am Thu from very latest 12z GFS. Fifth image shows forecast total snowfall from now through 6am Thu from latest NWS Blend of Models for both parts of the storm system combined, take forecast precip and snow amounts with grain of salt as details will change.

Stoked for heavy rain/snow! And stoked Nugs won last night! Rough ending for the Avs, oh well.