Quick Update: Chance of Rain and Snow Late Sunday and Monday

Our next storm system is still on track to bring rain and snow to portions of eastern Colorado late Sunday and through the day Monday, and a good round of accumulating snow for parts of the mountains. As it stands, there’s good confidence we’ll see precipitation out of this system, but whether any of that falls (and/or accumulates) as snow still remains quite uncertain. The latest runs of the GFS/Euro remain generally too warm for snow in Denver, but do have accumulating snow for higher elevations west and south of the metro by Monday night.

Latest infrared imagery shows our storm system spinning through Nevada this afternoon. Out ahead of it are the high clouds and breezy conditions we are experiencing today across eastern Colorado.

Environment Canada

Precipitation
Models produce anywhere from 0.2 to 0.4” QPF with this system, with most of that falling from early Monday morning through Monday evening. The GEM and Euro both setup the heaviest band of precipitation between Denver and Fort Collins, with the GFS focusing the heaviest totals along the Palmer Divide.

Snow
The typically cold-biased Canadian model continues with the best chance for precipitation falling in snow in Denver. Its latest run produces anywhere from 1 to 6” of snow, mainly west of I-25, with the focus of the heaviest snowfall along the Front Range in Boulder county. The Euro is slightly warmer and confines snowfall to slightly higher elevations across the southern and western Denver suburbs, and generally produces <1” of snow at that. The GFS… well, it’s just too warm for snow at elevations less than 7000 feet or so.

With the ECMWF being the compromise, I’m tempted to lean toward this solution. Even should temperatures cool enough for snow -- keep in mind how warm ground temperatures are after weeks of unseasonably warm temperatures, and with with most of the precipitation expected during the daylight hours, any snow that does fall may be mostly confined to grassy and raised surfaces.

The SREF mean also produces some snow for the greater Denver area. It too has greatest chances for anything measurable along and west of I-25, with mean snowfall ~1” over the last several runs. A few of it’s members produce upwards of 3” for DEN, but remain outliers at the moment. Again, will there be enough cold air?

SREF NOAA

We’ll see how things look after another set of model runs tonight, but for now, plan on much cooler temperatures, and a good chance for rain or snow by late in the night Sunday, through Monday. Here’s a look at today’s 12z GFS for 6hr precip + type early Monday. Note good snowfall across the mountains, with moisture working into northeast Colorado.

Weather5280 Models

I promised to keep this quick! More to come as needed… stay tuned!

Brendan Heberton

Brendan is founder of Weather5280. He is co-founder of FreshyMap, and develops software for geospatial data analysis and visualization.

Denver, Colorado
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