Winter storm warning for Denver on Friday; Heavy snowfall will bury the plains

I can't really remember the last time a multi-day, multi-stage, highly complex system not only outperformed its initial offering, but then performed better in the second half of the event. It looks like this system is trying to do just that, at least for Denver and the areas to the south and southeast.

Further north – we hear you – it's frustrating to be left out of the action, but it actually looks like there's hope of getting in on the action with this final push, we'll see.

How much snow so far?
Through this morning Denver has a record 6.2 inches of snow official (at DIA), with more for many of us, especially in the western and southern parts of the city. What a change from October!

The total number of snowfalls over three days shows who saw how much. Much of the state has seen measurable snowfall over the past few days, and there's a lot more to come!

The structure
Despite the snow we are seeing today, the main feature (low) is still So in our southwest. After the initial energy died down by Tuesday evening, there hasn't been much development – and that won't be the case until we move into the day on Friday and Friday evening turns into Saturday.

You can see in the current water vapor the low (red L) that is over Arizona this morning. It will gradually creep east and then turn northeast through this evening, eventually moving along the Colorado-Kansas border Friday night into Saturday.

You can see this in the animation below, which shows the positioning of the circles/blue as they move from our south to the east and eventually exit to the northeast.

This is a beautiful setting for lots of snow in eastern Colorado.

While the energy could Although areas further south and east are favored (versus Loveland, Fort Collins), I would say the trend today would be for more of these southern cities to get measurable snow before anything is said and done on Saturday.

When we look at the forecast QPF (precipitation) between now and Saturday night, we see a tremendous amount of water forecast for Southeast Colorado. More than 2 inches for a good portion of this area on this particular model. You'll notice lower totals towards Denver and north…but not dry!

Snowfall forecast
As mentioned above, a Winter storm warning takes effect tomorrow morning for the Denver metropolitan area and is valid until Saturday morning:

WINTER STORM WARNING IN EFFECT FROM 5 AM FRIDAY TO 12 PM SATURDAY MST…

* WHAT…Heavy snow expected. Overall snow accumulations will range from 7 to 14 inches, with the largest amounts south of I-70. Lighter totals of only 1 to 4 inches north of Boulder.

* WHERE…The Southern Front Range Foothills, Boulder and the western suburbs of Denver and Denver.

* WHEN… From 5am Friday to 12pm MST Saturday.

* IMPACT… Travel could be very difficult. The dangerous conditions could impact Friday morning and evening commutes.

We assume the following for the overall numbers, with room for adjustments by Friday.

Fort Collins: 3-8″
Boulder: 6-12″
Denver (downtown): 6-12″
Southeast Denver: 7 – 14″+
Conifer: 6-12″
Castle rock: 6 – 12″+
Elizabeth: 10-16″
Colorado Springs: 6 – 12″
Lemon: 10-16″

Modeled forecasts:
The European ensemble average is probably a good starting point, but is at the high end of what we think is potential in Denver. Still, overall it's hard to argue much here, and it shows that some of our northern communities could still stand a few inches off before things get through:

The HRRR (below) is closest to our current forecast. Note the highest totals in the southern and eastern Denver metropolitan area, with less gradient to the north and west:

And the 3 km long NAM, which shows high-end potential throughout the area – would undoubtedly be a boom Scenario!

Greatest boom and bust potential
Eventual route and to a lesser extent temperatures will impact snow totals. A slightly further east track would limit snowfall to Denver and the northwest, while a further west track would result in “boom” snowfall amounts in those areas. It is also worth mentioning, some The forecasts show snow mixing with rain at times at lower elevations, which would obviously affect the snowfall forecasts!

For the greatest boom We believe that the southern and eastern suburbs of Denver could end up under an impressive range when things really get going later on Friday, which could lead to another outperformance in these areas. Think Southeast Aurora.

For the greatest bust Potential, likely Denver and points to the north where temperatures and/or track could deprive us of uphill and peak snow levels.

All this to say: utmost confidence in the Plains, where BIG totals are expected, with Denver on the sidelines – a foot of snow is almost as likely as 4 inches. Yikes!

Planning and impact
This was an impressive event and will continue to be so through the end of the week and into the early part of the weekend. Some areas will also see a significant increase in winds throughout the day Friday into early Saturday. The areas at greatest risk for snowstorms are in the following areas: Elbert County, east/northeast El Paso County, Lincoln County, Kit Carson County, Cheyenne County and most of the southeastern corner of Colorado where snow has fallen or will come. These areas may experience gusts of 30 to 45 mph. There will be heavy snowdrifts and drifts, creating a dangerous situation, especially on Friday night. Below is an overview of where the greatest impacts are expected as the storm progresses. The impact could be adjusted by Friday. Stay tuned.

As for timing, look for snow showers to taper off today with a low chance of snow for most of tonight.

The chance of snow increases from south to north on Friday, with the best window for snow accumulation in Denver being between 6 a.m. Friday and 9 a.m. Saturday.