The active storm track of late will continue through the weekend and into much of next week. We discuss the four (yes four!) storms that will impact Colorado over the weekend and early next week. The last in the series has potential to bring significant snow to eastern Colorado.
The recent pattern has only been “active” in the sense that the jet stream is close by and has been helping to sling small-scale disturbances across Colorado about every 1 to 3 days or so. Since nearly all of these waves were quick-moving, weak, and lacked moisture, they didn’t change things much down here in the Metro area. We’ve enjoyed a stretch of unseasonably mild and dry weather, while the Mountains have seen bursts of accumulating snow and strong winds. The last day of below normal temperatures in Boulder was two full weeks ago on December 7th. Things are about to change, however.
NOTE: We are about to discuss the weather forecast for the next five days. This period will feature a strong 150 mph stationary jet streak near the Pacific Northwest. This jet will be spawning a multitude of weak sub-storms that then track into the northern Rockies. This is usually a recipe for uncertainty.
Animation of 500 mb height and vorticity from the GFS model for the next five days showing all the storms we will discuss.
Storm #1: Chilly Saturday with light snow
First up is a speedy storm that will move across the Front Range on Saturday. Shown below is the 500 mb vorticity map (left) and 800 mb temperature map (right). A combination of decent large-scale lift and low-level upslope will allow colder temperatures and light snow to overtake the region. Saturday will be our first day of below normal temperatures in more than two weeks. Highs will remain in the 30’s with scattered snow showers possible through the daytime hours. A few flakes up to 1″ of accumulation is possible across the lower elevations on Saturday, with up to 2″ in the highest Foothills west of town. The Mountains will catch the brunt of this first storm with 2 to 5″ expected by Saturday night.
Storms #2 / #3: Mountain snow late Sunday & Monday
As the first storm exits eastward, two quick-moving storms will follow in its tracks on Sunday and then Monday. These systems will likely be even weaker than the first storm leading to less impacts for the Front Range. In the 500 mb map for Sunday evening (below on left), we can trace the flow into Colorado backwards to Oregon and Northern California. This specific pipeline of winds favors the Steamboat area for heavy snow. Despite Sunday and Monday’s storms being quite tame, the persistent northwest flow with Pacific origins will likely lead to a lengthy period of snow in the Mountains. Some models are indicating more than a foot around Steamboat Sunday night into Monday night. In fact, most of the northern mountains should do quite well during this time.
Downslope with be the story for the Metro area on Sunday and Monday with mostly sunny skies and temperatures in the 40’s.
Storm #4: Christmas night into Wednesday – The BIG one?
Our final discussion covers a potential major winter storm which you have undoubtedly already heard about. As we have been talking about with our Premium subscribers, a strong piece of upper-level energy is forecast to take a deep dive southward into the Four Corners region on Christmas Day. We have been watching this system quite closely the last few days, with models wavering all over the place on its location and intensity (as one would expect this far out). Despite this, currently the GFS and Euro models have come into relatively good agreement on its timing and track. Not bad for five days out. The storm’s projected position in central Arizona at 5:00PM on Christmas Day is depicted below…
You may be thinking to yourself…”Hey…isn’t that storm a little bit too far south for snow in Boulder?” Usually, yes, this positioning would bring about some serious cause for concern in our minds when making a snowfall forecast. However, there is some good news, if you want lots of snow, that is. The models are in surprisingly good agreement that this storm will then slowly take a northeast track into southeastern Colorado by Wednesday evening….putting it just about in the “sweet spot” for juicy Front Range snow.
One thing is a near-certainty, somewhere is going to get slammed by this storm with heavy snow. It has all the makings for it to happen: the huge breadth, slow movement, strong intensity, deep moisture (see below), and cold air. It’s all going to be there. We just need to wait and see where this monster will end-up come next week. 
The latest run of the GFS model produces some big snow totals across much of Colorado (see below). Typically this model is the one that will grab the attention of news outlets desperate for some snowstorm readers. Admittedly, the GFS is a key factor in all of our forecasts as well, but we of course have a deep understanding of its biases, especially in the western United States and Colorado.
This far out, we must look at the ensembles as well. Here you will see that the picture isn’t so clear, even in the eyes of just the GFS. Most runs indicate a swath of 6 to 12″ of snowfall stretching eastward across the Plains of Colorado. Some even develop this around Boulder and Denver. The highest snow amount in this panel for Denver is 9″. The lowest is 1″. The median is just 3″! This should help to keep your expectations tempered.
The take-away for now:
The Front Range is definitely in the “zone to watch” for significant snow, but we cannot (and will not) put faith in the forecast track of a cut-off low pressure system five days out. No ifs, ands, or buts about it. There is a substantial chance that Denver and Boulder will see some snow beginning Christmas evening or night through Wednesday of next week. We will need to wait and see exactly how much snow that will be. It’s still far too early. Our gut feeling right now is that this storm isn’t going to bounce back as far north as the models are showing. That just isn’t a climatologically favorable track. Please, Mother Nature, prove us wrong.
Share this forecast:
.
You must be logged in to post a comment.