The State of the Atmosphere: Sunday, February 16th, 2020

As we discussed on Friday, our next change in the weather across Eastern Colorado arrives tomorrow. While some of the more bullish snowfall outputs we saw some models producing last week look much less likely today, we do expect to see pockets of snow across Eastern Colorado over the coming days. First Monday afternoon and overnight into Tuesday, then again possibly on Wednesday.

For today and tonight the snow will remain confined largely to the high country. HEAVY snow is ongoing across the northern and central mountains, where some locales could top two feet of snow by Monday evening. The GFS forecast below shows where the heaviest snowfall is expected through midday Monday:

By Monday afternoon and overnight Monday into Tuesday some of that snow will make its way onto the plains. A cold front is due to arrive Monday afternoon, and behind it a shallow upslope flow. While not a terribly moisture-heavy system, we do expect to see snow develop across the greater Denver metro area, foothills, and Palmer Divide Monday PM –– continuing off and on through the overnight hours and into Tuesday.

This setup isn't all that favorable for the urban corridor to see a lot of snow. Instead we expect the greatest totals to end up in the Foothills and across the Palmer Divide where at least some upslope is forecast. Colorado Springs may end up with a bit more snow than the northern cities with this setup as it looks right now.

The GFS depiction of this is below, showing mainly 0 - 2" for the northern urban corridor, Trace - 3" for the Denver area, and some spotty 2 - 6" totals for the foothills.

The NAM model once showed much greater snowfall potential has since backed off considerably. Here's the latest snowfall forecast through early Wednesday –– clearly if correct, a non-event for the urban corridor.

Importantly, these are both through Wednesday morning. Yet another surge of cold air is expected to arrive Wednesday, and with it an increase chance of snow. Given how this month has gone it seems reasonable that at least one if not both of these snow chances will deliver some accumulation across the region. At the moment, for Denver anyway, it seems like the secondary push on Wednesday may off a bit more potential in that regard, but should Denver manage a coating to 2" Monday into Tuesday I would not be surprised.

With that, we'll go 0 - 2" for most of Denver and points north/northeast. With a Trace - 3" for the western and southern suburbs, and 1 - 4" where we may see a bit better upslope Monday night and Tuesday. Again, these totals are Monday and Tuesday, and do not include any additional snow we may see Wednesday.

For temperatures... look for another chilly week, at least through Thursday, as temperatures will warm into the 40s ahead of the cold front on Wednesday, then stay in the 30s both Tuesday and Wednesday behind the two shots of cold air discussed above. The GEFS anomaly forecast for Tuesday (below, top) shows plenty of cold air in place across the state:

With even cold anomalies for Wednesday:

GFS MOS guidance has a high of 35°F on Tuesday and 33°F on Wednesday in Denver, but a BALMY 59°F showing up for Friday if you care to believe!

For you planning, look for a that chance of snow to increase Monday afternoon and evening, with some potential for a slow Tuesday commute should we see snowfall materialize across the urban corridor. We'll then keep an eye on Wednesday's front, and update as needed over the coming days.

Your hourly planner for Denver: