San Juans: Telluride, Red Mountain Pass, Silverton, Coal Bank Pass, Purgatory, Wolf Creek
6am New Snow
6am Powder Potential
Denver and surrounding suburbs: Lakewood, Westminster, Aurora, Highlands Ranch
6am New Snow
6am Snow Accum. Chance
Thursday will be another mild/warm day. Highs in the 70s on the Front Range.
Changes coming on Friday ahead of a one-two punch of systems.
Warmer storm on Friday (heaviest snow with SW flow initially in the San Juans in the late morning/afternoon), with a transition to westerly/NW flow on Friday night / Saturday morning. A few inches of snow for northern Colorado, better totals in the San Juans. Some thunder is possible. Precipitation would generally fall as rain on the Front Range.
First wave ends on Saturday afternoon, colder and stronger wave on Saturday evening / night and into Sunday night. Initially favors the San Juans with SW flow, then a good shot of NW by Sunday afternoon with decent totals in the northern mountains by Monday morning. The Front Range should get some snow with this wave.
Overall, best snow totals lean towards the San Juans and northern Front Range mountains (RMNP etc.) but totals should be a little more even distributed as compared to our last storm cycle.
Ongoing snow chances and colder temperatures across the state throughout next week, with snow favoring the northern mountains.
Retrospective & Short Term
Meteorological spring started on Tuesday, and it’s certainly felt like it! Denver tied the record high of 74 degrees for March 2 (previously set in 2009), and tomorrow’s forecast of about 75 degrees has a small chance of tying or besting March 3’s record of 76 degrees (set in 1921).
In fact, the 75th percentile forecast from the Blend has temperatures in the low 80s for Denver. This definitely seems too high, but it’s pretty interesting to be seeing these values in play:
The deterministic runs have had highs in the low to mid 70s, which is much more realistic. To counterbalance the past map, we’ll share how that looks:
With some upper-level moisture in play, mountain wave clouds over the Front Range will likely be the deciding factor in which areas get close to their record high temperatures and which areas don’t, as was the case today.
According to SWANN, Colorado’s high country is generally running a snowpack deficit, especially with snow melting pretty quickly this week:
The areas running the largest deficits appear to be the Tenmile/Mosquito, Sawatch, and Park Ranges. Data from SNOTEL sites backs up the idea that the previous storm cycle was certainly beneficial but not enough to tip the scales across most of the state:
We have a decent storm lined up for the weekend (actually, a one-two punch of two separate systems), and then we transition back to more zonal flow by the end of next week, which should be tilted just northwesterly enough to keep the door open for weak disturbances to provide some refreshers to the northern mountains every few days.
Friday will be another mild day, but cooler air will begin to advect into the state, knocking high temperatures down by a few degrees, with a rapid cooldown in by the evening hours. This transition will be earlier in southwest Colorado.
The culprit is a closed low which should track east across the desert southwest on Friday, which will help orient southwesterly flow aloft before an even stronger center of low pressure drops into the region later on Saturday.
For the San Juans (Telluride, Wolf Creek, etc.), this puts snow in the forecast for Friday morning, though the heavier stuff wont get going until the afternoon as better jet dynamics take hold.
Per usual, with southwesterly flow, totals drop off further to the north and east, with the onset of heavier snow being later as well. For instance, guidance doesn’t show better snow chances for Berthoud Pass until around sunset on Friday.
One thing to consider with this initial plume of subtropical moisture is that snow-liquid ratios will struggle to get too far above 10:1 – meaning fairly wet, dense snow.
As the low tracks over the mountains and down onto the plains, it will undergo lee cyclogenesis. Unfortunately, with the center of low pressure looking to emerge over the Cheyenne Ridge, the impacts of the re-intensifying system look to mostly be contained north of the Colorado border.
This should at least get more westerly, even northwesterly flow going on Friday night and into Saturday morning, but there’s a decent amount of uncertainty there. Still, expect the northern mountains to see the best snowfall production on Friday night and into Saturday morning.
In the Front Range, the placement of the surface low to our north will cause downsloping westerly winds. This not only reduces the chances of precipitation but will also keep things warm enough where the initial chances of precipitation on Friday evening come in the form of rain, maybe even with a rumble of thunder or two! Actually, thunder is possible across Colorado with this initial wave of warmer, more unstable air:
Though it will still be snowing at this time, here’s a look at what you might expect on Saturday morning, when thinking about skiing:
The above totals from the Blend are fairly in line with the latest Euro model guidance. Probabilistic guidance paints a similar story:
Saturday and Sunday
Snow looks to briefly wind down by Saturday afternoon before the next system brings in colder air and another, more productive round of snow. Snow should be a little fluffier with these colder temperatures aloft.
The heavier stuff starts back up on Saturday night and continues into Sunday afternoon, when flow begins to turn northwesterly and dry out. This does provide a window on Sunday afternoon and evening for the northern mountains to pick up more consistent snowfall.
In the Front Range, the best chance of snow comes from Saturday night to Sunday night.
Here’s what the Blend thinks for totals from Saturday morning to Sunday morning:
…and Sunday morning to Monday morning:
You can certainly see how northwest flow should do some work later on Sunday!
Altogether, guidance actually has pretty even totals across Colorado’s mountain ranges. For both waves of snow, the San Juans and Elks will pick up the heavier snow first, with productive shots of westerly and northwesterly flow at the end of each of those waves.
Deterministic totals aren’t too shabby:
The real question is – do we think this guidance is too conservative, or too optimistic? It’s hard to say right now. The interactions between two closed lows are tough to model, and uncertainty is quite high at the moment. We can see on probabilistic guidance that the deterministic snow totals in the above map are kind of sitting nicely in the middle of most area’s interquartile ranges.
It also reveals that the San Juans certainly have the highest powder potential, despite how similar totals look across Colorado’s mountains on the deterministic map.
The other potential winner looks to be the northern Front Range, which could get walloped with snow depending on how lee cyclogenesis pans out.
Model guidance is a mess after the weekend, but in general, meridional flow slowly returns to more zonal flow over the course of next week. Any shortwave in flow aloft will get another round of snow going in the mountains, with the northern mountains favored. Models currently expect anywhere between 3-12” of snow from Monday to the following weekend, but it’s difficult to pinpoint exact impacts at this time.
We’ll say goodbye to more spring-like conditions for at least a week or so, with much colder air in place during that time and snow chances (even if only light/moderate) every couple days or so. Nothing like last week though…that was kind of brutal!
We’ll post up a more solid snow forecast tomorrow, probably with the comparison/verification tool.
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