Winter Weather Highlights in Place, Heavy Snow for Some, Avoid Travel West and South of Denver This Evening if Possible

Not much change this morning as compared to our update yesterday. Models have done their usual back and forth with placement of heaviest QPF, but... all in all everything appears to be on track.

Main updates today are that the National Weather Service has issued a Winter Weather Advisory for Denver for this evening, and a Warning for Colorado Springs. The Denver Advisory focuses on heavy snow potential this evening, mainly along and west of I-25. We continue to expect a sharp gradient of snow accumulation from southwest to northeast across the city, barring any rogue bands that manage to set up on the northeast side.

Timing
The Advisory goes from 6pm this evening through 8am Thursday morning, though we expect for the Denver area at least the bulk of what snow we do see will come this evening, and will be winding down pretty quickly after midnight. The latest precipitation and temperature timeline shows probabilities jumping up after about 4pm this afternoon, and remaining high through the overnight hours. Thursday morning's commute is likely to be slick for areas that see the heavy snow, but most of the snowfall should be done –– especially north of the Palmer Divide.

A look at the latest HRRR reiterates a number of things we've been discussing for several days now. The timing, which looks on track, and where the focus of the heaviest snowfall is likely to be: at higher elevations south and west of Denver. While Fort Collins, Greeley, and even DIA are likely to see some rain and snow today, the greatest potential for heavy snow will be south and west of these areas.

Below are a couple of snapshots of the HRRR forecast for later today. Keep in mind this is just one model and one model run... but the IDEA is likely a good one, for both timing and placement of the snow. This will vary in detail with each run, but is meant to give a sense of what we expect later today...

5pm: Snow is picking up across the Front Range foothills west of Denver and rain and snow across the Palmer Divide:

7pm: Snow has picked up across town, with greatest snow production south and west of the city (notably nothing at DIA):

9pm: Snow is ongoing, with heaviest focused along and west of I-25 from Denver/Boulder through Douglas County and on into Colorado Springs:

12am: Snow is ongoing in the foothills, but bulk of heaviest snowfall is shifting into Southern Colorado:

Snowfall totals
We haven't made any adjustments to our going snowfall forecast. Given the convective nature of this event, we expect plenty of boom and bust reports come Thursday morning. These wide ranging total potentials are hard to capture on a map... so instead we try to generalize, with the areas in general that stand the greatest chances at seeing the heavier snow.

Last night one model brought upwards of 6" of snow to Denver, this morning it backed off considerably. Is that possible? Absolutely. The atmosphere is juiced and this one certainly has the potential to over perform in spots. That said, probabilistically, Denver's odds for over performing aren't great, and 1 - 4" should cover the city well in most scenarios, with highest of those totals southwest, lower northeast.

I personally will be on the lookout for a rogue snow band north/northwest of Denver busting our forecast up between Denver and Boulder, but otherwise think this forecast will hold pretty well all things considered.

It'll be a fun one to watch. Plenty of moisture and a roaring jet is prime setup for surprise totals. As we outlined yesterday areas we favor for a boom remain the same... areas like Castle Rock and Colorado Springs where snowfall rates could reach 2" and hour at times. Denver... I'm torn. It feels like the boom potential is ↓ this morning and bust potential ↑, but I like myself a good snow band so I for one am rooting for one nonetheless.

Impacts
Travel will be impacted from this afternoon through Thursday morning from the Denver area south to the state line. If you can avoid travel between Denver and Colorado Springs this evening and overnight... please do.

For most areas this Wednesday evening commute should be okay. For higher elevations to the west and across the Palmer Divide we could see some heavy snow showers impact that evening commute, however, with lower odds in the cities –– but not an impossibility.

Worst of the travel is expected to be between 6pm and 3am between Denver and Colorado Springs, but with the heavy snow that's expected in this area, a slow Thursday morning commute should be planned for.

Conditions will improve through the morning on Thursday, with a dry Thursday evening commute in the forecast.

Brendan Heberton

Brendan is founder of Weather5280. He is co-founder of FreshyMap, and develops software for geospatial data analysis and visualization.

Denver, Colorado
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