If there were any doubts that changes were on the way, those quickly went out the window early this morning. After reaching a high of 22 degrees at 4:45am this morning, temperatures across the region have fallen into the teens this afternoon, and will drop into the single digits this evening.

Latest surface observations have temperatures in the single digits and below zero across Wyoming and Montana, that’s where we’ll be tomorrow.

MOS guidance for temperatures Tuesday keeps “highs” in the lower single digits for Denver, though we main struggle to make it above 0 in many locations. This is a very cold airmass. Latest GFS MOS is printing out -15 degrees for a low Tuesday night into Wednesday.

As for the snow…
One thing we knew for certain is that this system would be packing very high SLR, meaning a very light, fluffy snow, that can quickly accumulate to several inches. Snowfall ratios of nearly 30:1 have already been reported across parts of the region.

With that, many locations will do quite well with this system, as long as we keep the snow going. The Denver area has already seen 1 - 3” of snow since early this morning, and we expect snow to continue off and on into Tuesday.

Snowfall reports as of 1pm:

• 2.6” 2 miles SSW Boulder
• 5.0” 4 miles West Boulder
• 3.0” Genesee
• 2.5” Denver

We will likely not be changing the snowfall forecast map already published, the general forecast looks okay. Higher snowfall totals will favor upslope areas prone for over-performing, but these locations are already in the 4 - 7”+ range, which covers locally higher amounts. For Denver, we’ll likely see snowfall continue through much of Monday night, but outside of heavier bursts, snowfall will generally be light. We’re watching a bit more energy move in, which might enhance snowfall for a period later this evening. We think that most locations are covered in the 2 - 6” range we already have -- with higher end totals being near 6” in the city. On the flip-side, the National Weather Service is calling for 5 - 9” for Denver, so we’ll see how this goes.

Roads will remain treacherous over the next day or so here until we can get a break in the snow and crews can get ahead of this thing. Side roads will likely remain a mess far after the snow stops falling as there won’t be much help from Mother Nature in melting them.