Our quiet weather pattern will give way to a colder and perhaps snowier weekend across Northeast Colorado as we round out 2019.
This system has been long broadcast by weather models to move through the region. In the last 24 to 48 hours or so we've seen a bit of a shift in the track –– and with that shift, we see a greater chance for snow across the Northeast Plains than was indicated in our update earlier this week.
The greatest confidence of an impactful snow is shaping up to be east of Denver, including most of the northeastern and east-central plains of Colorado and on into NW Kansas and Western Nebraska. Here we see a Winter Storm Watch posted for tomorrow night through much of Saturday night with 4 - 8" of snow expected and very gusty winds at times causing poor visibility and tough travel conditions. The Watch is in the shaded blue below:
Closer to the urban corridor the eventual impacts are a bit more up in the air. The GFS, for example, has been covering the Denver area in several inches of snow in its most recent runs... while most other data shows the heaviest snow will end up east of the urban corridor, as pictured above.
Considering the GFS is such an outlier, we'll hedge toward an eastern solution as well. Not to say we won't see any snow in Denver, but accumulation if any is expected to be on the low side at this time.
For the Palmer Divide south of Denver we could see a period of heavier snowfall making for tough travel Saturday morning and amounting to several inches, with again a less favorable set up for the Colorado Springs area south of the Palmer.
For Denver we've got highs near 40 on Friday with an increasing chance of rain and snow showers through the afternoon and evening. The best chance of snow looks to come between midnight tomorrow night and 6pm Saturday, with probabilities dropping off Saturday night. Temperatures will be cold, but not frigid, with the city perhaps even climbing above freezing Saturday with those scattered snow showers around:
East of Denver the system looks more impactful. A look at probabilities near Akron, CO shows snow is likely most of the day Saturday, with even some good odds we'll see some showers move through by midday on Friday. You'll also note the gusty winds expected Saturday across the Plains:
For snow totals the map below is a great starting point. We'd like to see another round of data tonight before getting too attached to any numbers as we've seen a great amount of fluctuation in the track of this thing in recent days.
That said, some ballpark numbers from where things sit as of midday today are as follows:
Also worth noting, the Southwest Mountains are again going to get buried with this system, with the higher peaks expected to see 1 to 2 feet of snow through Saturday night.
Now, since plenty of folks are asking about the GFS, could it be right? Absolutely. Probabilistically it doesn't appear to be, however, with even its own ensemble suit not showing near the potential for heavy snow in Denver that its operational model is.
A look at probabilities from the morning run of the European ensemble, we see about an 80 to 90% chance of 1" or more of snow for Denver (much lower for points north of the city), and those high probabilities extend well south and east of the Denver area:
When you look at the probability for 3" or more... well, it appears to be around 10% from this model for Denver. Higher east? ✅But actually not all that impressive odds even there given our 4 - 8" outlook.
And finally, our gamblers. They also reenforce our caution on jumping on some of the big numbers from the operational models we've seen. A couple inches in play for most cities along the Front Range, but not a done deal. We're still showing Colorado Springs with higher boom potential than Denver given the tendency for this thing to want to lean southeast as it moves through:
Again, uncertainty weighs into this. The eventual track isn't fully agreed upon just yet. We've seen it move much further north in recent days than early data would have suggested... so a better setup for Denver is still on the table, if a low probability for such an event at this time.
For now plan on a wetter, cooler, and windier weekend beginning Friday afternoon and carrying into Sunday morning for the Eastern Plains. The best chance of accumulating snow at this time looks to be across the Palmer Divide and east-central/northeast Plains. We'll be tracking the storm closely and let you know if anything changes in that regard. Maybe the GFS has one final surprise up its sleeve for 2019.