In this week’s forecast, we cover the pleasant weather for Christmas Eve and Day, potential snow amounts for Wednesday’s storm, and the big cool-down coming later this week. Unfortunately, this Christmas will not be a white one for the lower elevations. Head to the Mountains if you want snow.
Christmas Eve & Day will be pleasant
As we discussed in our forecast update on Friday, a weak disturbance is moving across Colorado today embedded in the west-northwest flow. This can be seen in the 500 mb map below. This particular system has a stream of Pacific moisture with it which has been producing fairly widespread snow in the Mountains of western Colorado this morning.
GFS 500 mb vorticity map for Monday
Snow showers will continue into the evening hours for many areas….really adding to the Christmas ambiance in the High Country. Winter Weather Advisories are in place around Steamboat and Aspen where 4 to 8″ of snow are expected today. Elsewhere, 1 to 4″ are in the forecast.
PowderCAST snowfall forecast for Monday
Surprisingly, some of this moisture is making it out across the Plains in the form of wavy cloud cover. The view from GOES-East is shown below at 8 AM. We anticipate a mix of clouds and sunshine through the day Monday. No precipitation is expected east of the Continental Divide with low-level downslope in place. Highs around Boulder and Denver will top out in the 40’s.
GOES-East visible satellite image from 8AM Monday
Christmas Day will be similar across the lower elevations, but we do expect a little more sunshine. This is because a small-scale ridge will briefly be moving across the state (see below). Tuesday will also have temperatures in the 40’s with partly cloudy skies. Sorry folks….you’ll need to head to the Mountains this year to find any snow on Christmas.
GFS 500 mb vorticity map for Tuesday
A chance of snow Wednesday
Unfortunately, a “chance of snow” in Boulder and Denver is all we can say for the strong southern-track storm system that will be moving across the Desert Southwest mid-week. We hoped that we would be wrong, but despite some early hints that the Front Range could be in the mix for significant snowfall, it will be a swing and a miss for us. The reason: the storm gets tugged apart by the polar and sub-tropical jet streams. The northern portion that moves into Colorado is currently projected to be very weak. You can see the tiniest hint of rotation at 500 mb below over Denver. The bulk of the energy from this storm will remain too far south, entering West Texas Wednesday night. We’ll refrain from calling this storm system a “Four Corners Low” as its track is too far south for even that.
GFS 500 mb vorticity map for Wednesday
So where does this leave us? Well for one, the Mountains are a lot less dependent on track for snowfall than the Metro area is. They will do okay from this system, particularly across southwestern Colorado late Tuesday night into Wednesday night where up to a foot of snow is possible. The northern Mountains will see less, likely somewhere around 3 to 6″.
For the Denver Metro, chances for snow are looking fairly good Wednesday afternoon into Wednesday night, but nothing too widespread or heavy is anticipated. We’d still like to see how the wind-fields evolve in the models for this northern branch of the system around our area. The weather models are still torn on this facet…which ultimately will determine if we see a few inches of snow or almost nothing at all. Our forecast for now has a few flakes up to a maximum of 3″.
GFS ensembles precipitation plumes for the week in Denver.
Cold late-week
After Wednesday’s disappointing snow event, the story to end the week will be the cold air. This air will be driven southward in the wake of the departing low pressure system into eastern Colorado (see below). The GFS and Euro models are both showing the potential for weak upslope to set-up across the Metro area during this time. You can see this below if you look closely around Boulder. Due to this upslope, there is some indication that a few snow flurries may accompany the cold air to end the week (this is noted in the GFS ensembles plumes above for Denver). We’re not convinced yet on this facet, but nonetheless, if there is any snow, it should be very light and not amount to much. High temperatures Thursday and Friday will be in the 20’s. Yes…the 20’s!
GFS 800 mb temperature and wind forecast for Thursday morning
Another strong storm system is expected to move well to our south again to end the week on Friday. At this juncture, it likely won’t have any impacts on the Front Range. Snow in the southern Mountains will be the primary concern with another 6+ inches possible. Fortunately, this is the portion of the state that needs it most.
PowderCAST snowfall forecast for Friday (left) and the current snowpack in Colorado (right)
From all of us at BoulderCAST, have a safe and joyous holiday!
Forecast Specifics:
Monday: Partly cloudy and mild. Highs in the upper 40’s on the Plains and upper 30’s in the Foothills.
Christmas Day: Partly cloudy and dry. Highs in the middle 40’s on the Plains and in the low 30’s in the Foothills.
Wednesday: Mostly cloudy and cooler with a chance of snow showers in the afternoon and evening. Light accumulations will be possible. Highs in the middle 30’s on the Plains and middle 20’s in the Foothills.
Thursday: Partly to mostly cloudy and cold. Highs in the upper 20’s on the Plains and upper 10’s in the Foothills.
Friday: Partly to mostly cloudy and cold with a slight chance of isolated flurries. Highs in the low to middle 20’s on the Plains and in the upper 10’s in the Foothills.
High Country: Snow will be widespread across the Mountains of western Colorado through the day Monday. Amounts will range from 4 to 8″ around Aspen and Steamboat, with 1 to 4″ elsewhere. Tuesday morning will see a lull in the action, with snow returning again Tuesday evening through Wednesday evening. This second wave will favor southern Colorado with 6 to 12″ possible, 3 to 6″ elsewhere. Finally, another strong southern storm will impact mainly the mountains of southern Colorado on Friday, with yet around dumping of 6+” of snow looking possible. Check PowderCAST for forecasts for all the Colorado ski resorts.
DISCLAIMER: This weekly outlook forecast was created Monday morning and covers the entire upcoming week. Accuracy will decrease as the week progresses as this post is NOT updated. To receive daily updated forecasts, subscribe to BoulderCAST Premium.
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