Brendan Heberton

Call it shortwave season
[https://www.weather5280.com/blog/2015/04/07/the-importance-of-shortwave-troughs-and-how-to-identify-them]
, call it picking up the scraps of the more meaningful weather systems to our
east, call it what you will – but the relatively active weather pattern we've
seen this month continues today and through the next week at least for Denver
and eastern Colorado. 

While today's event
[https://www.weather5280.com/2022/01/18/icing-possible-with-wednesdays-temperature-drop] 
won't deliver much in the way of moisture, we are sitting light snow and
freezing drizzle along the Front Range and Eastern Plains today making for some
slick roads and sidewalks, and will keep the region feeling very wintry through
the night. 

The next system to impact the region will drop out of the northern Rockies
Thursday night into Friday, and eventually form a closed low southwest of
Colorado Friday into Friday night. 

This setup isn't exactly ideal for snow across the northern urban corridor, but
there could be enough moisture and lift in place to provide another round of
light snow for the Denver metro area, and perhaps several inches for the
foothills west of town and western Palmer Divide similar to last week's snow.
With the track of the low, and so much of the energy dropping southwest, the
southern foothills and adjacent plains would be favored for the more meaningful
snow with this event, as indicated by the latest European 24 hour snowfall
forecast ending Saturday morning: 

Still, we'll need to keep an eye on this system. Some models have a bit more
snow for the western and southern suburbs of Denver, and there remain a good
deal of wobbles in run-to-run outputs from models on the eventual track of the
low. 

For Denver this equates to about a 50% chance for snow on Friday: 

With a bit better chance for Colorado Springs: 

The weekend will dry out across the region, with cool temperatures in place
Saturday, and seasonal temperatures with highs near 50°F for Sunday. 

Next week
A lot of murmurs about the potential for a more meaningful/widespread snow event
during the early to middle part of next week. And while it's true, models are at
times advertising a nice snow event for the Front Range and Eastern Plains of
Colorado as yet another shortwave (albeit slightly stronger shortwave) moves
through, the details are far from certain, and the pattern overall doesn't favor
terribly wet or long-lasting snowstorms. 

If we look at the GEFS precipitation forecasts by ensemble member (y axis), we
see there's definitely something showing up for next Tuesday/Wednesday, but very
little consensus on timing and how much precipitation we are likely to see.
You'll note that this particular model is in much better agreement around our
odds of seeing moisture today (though light) and Friday vs next week. Each green
rectangle represents a 6 hour precipitation total as forecast by the 30 model
ensemble members. Some of those members are entirely dry next week! 

To that end, we are not surprisingly seeing large swings in solutions between
models and even between themselves run-to-run. Take the European's 24 hour
snowfall forecast ending next Wednesday morning from it's overnight run: 

And compare that to this morning's run, which is way faster with the progression
of the trough, and has a fraction of the snow across the region! Ouch. 

So, an active pattern? Yes. A wet one? Not terribly, though next week's system
should be watched in case we can piece together something more meaningful. 

With help from these continued quick-hitting shortwaves, the European ensemble
keeps the Front Range foothills of Colorado just above average for precipitation
through the remainder of the month. The Eastern Plains will be near average
(which doesn't mean much in January!), and the Western U.S. will remain locked
in a dry pattern – on average. 

The presence of these quick-hitting systems moving through every few days will
keep us on the cool side regionally, at least for the next week, with
temperatures in the 30s and 40s most days, outside a brief warmup Sunday/Monday. 

February? 
The pattern will try to revert to a more active storm track across the West as
we head into the final days of January and on into February. Most guidance
supports a return of the -PNA for February, even as the flip has been delayed
several times. 

Should this materialize as expected, the cold that is locked in the east for the
next couple of weeks... 

Should be focused across the Pacific Northwest and northern tier for the first
weeks of February...

And, should things progress as anticipated, we should see the more active storm
track emerge in the west once more, after a very dry January which proceeded our
wet December. You'll note, for Eastern Colorado and the central plains states,
average to below average precipitation is forecast currently for February, even
as the large-scale pattern shifts.

Tracking additional snow chances for Denver, Eastern Colorado through end of January