The first 17 days of December have been dry, with most of the western US seeing less than 40% of average precipitation.

Following dry and mostly sunny weather on Monday, Tuesday, and Wednesday, the final 10 days of December should be more active with perhaps average or above-average precipitation.

The first storm will arrive late Wednesday night or early Thursday morning, and snow should fall for most of the day on Thursday and perhaps linger through Thursday night.

An early look at the forecasted snow amounts shows 3-6 inches for most mountains, via the European model.

The University of Utah ensemble forecast, which is a collection of many versions of the American GFS and Canadian models, shows 1-10 inches by Friday morning with an average of 4-5 inches. This is forecast is for McClure Pass, which I often pick as a forecast point 3-5 days before a storm because it lies in the middle of Colorado.

Notice that most of the model versions show additional snowfall from late on the 22nd through late on the 23rd ... can we add another 3-6 inch storm in the days leading up to Christmas?

I think so, but I'll talk about that below in the extended forecast.

For this week, if you want to ski fresh snow, target Thursday midday through the afternoon, and also Friday morning. Snow totals should be roughly 3-6 inches.

The snow on Thursday should end late Thursday night or very early Friday morning. As I mentioned, there might be soft turns on Friday morning, and then the weather on Friday will likely be dry for most of the state with the potential for snow showers in the northern mountains.

On the night of Friday, December 22nd, an Arctic cold front will arrive in Colorado.

The combination of the cold front near the ground and energy in the middle of the atmosphere will create snow from late Friday night through late Saturday night. My best estimate at this point is for another 3-6 inches from Friday night through Saturday night, with soft skiing on Saturday and again perhaps on Sunday morning.

When the Arctic air moves into Colorado later on Saturday and into Sunday, temperatures will plummet to near or below 0F, especially near and east of the divide and north of I-70. The coldest air may push further south and west than this, but that's not the most likely scenario at this point.

The Arctic air mass will be very dry, which is why we will likely not see much accumulating snowfall once the truly frigid air moves in, though any moisture that does linger could turn into an inch or two of super fluffy snow.

Here is the forecast for the temperature compared to average, starting on Wednesday night and ending on the day after Christmas. You can see the initial push of cooler air on Thursday (blue colors) and then the second push of Arctic air on Saturday night and Sunday (purple colors).

The bottom line is that you'll likely ski fresh snow on Thursday, Friday, and Saturday, then Sunday and Monday will be very, very cold with the possibility of somewhat warmer temperatures starting around December 26th.

The weather pattern will be active across the west during the final few days of December and into early January, though I have no idea what exactly that will mean for snow here in Colorado. Stay tuned.

Thanks for reading, and it's nice to have some action to talk about!

JOEL GRATZ

Ten years ago today, on December 18th, 2007, I wrote my first public snow forecast via an email called "Colorado Powder Forecast".

On that date, there was no website, no idea about "OpenSnow", and no business plan. I was just a guy who had liked weather and snow since age 6, had a degree in meteorology, became addicted to powder when I moved to Colorado, and resolved to hunt down powder and to loop in a list of 38 friends who also liked to ski deep snow.

Ten years later and now Colorado Powder Forecast has morphed into a group of weather forecasters across the country, a profitable and growing business, and I honestly cannot think of any work that could bring me more joy than writing snow forecasts and learning about and running this business.

Thank you so much for your support over the years. About 99% of the growth of this business is due to word-of-mouth, and that means so much to me because it's a sign that you trust me and my team to provide useful information in your hunt for snow.

If you are near Boulder tonight (Monday, December 18th), you are invited to my 10-year anniversary party.

* West Flanders Brewing in Boulder, CO
* Starts at 700pm
* I will give a short talk to begin the evening
* Wear your Colorado Powder Forecast t-shirt from 2011 and I'll buy your drinks:-)
* Happy hour prices all night for drinks and appetizers
* Details and RSVP: https://www.facebook.com/events/836050909911243/ 

Also, in honor of my first forecast, here is a coupon for 50% off a 1-year OpenSnow All-Access subscription. This code will only work on our website as Apple and Google do not allow discounts for in-app purchases.

Coupon code: cpf2017

The code will only work today, Monday, December 18th. 

If you already have a subscription (thank you!) and would like to apply 50% toward your renewal, email [email protected] and I'll apply this discount to the first 50 people. UPDATE at 1000am: we have already reached 50 people. If you ALREADY HAVE a subscription, sorry that you weren't a part of this first 50 group, and thanks for your support! If you do NOT have a subscription, please use the code cpf2017 to sign up for 50% off.

Again, thank you for your support, and I am looking forward to another 10+ years of forecasting deep powder!

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https://opensnow.com/state/co

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Geography Key

Northern Mountains
Steamboat, Granby, Beaver Creek, Vail, Ski Cooper, Copper, Breckenridge, Keystone, Loveland, Abasin, Winter Park, Berthoud Pass, Eldora, Rocky Mountain National Park, Cameron Pass

Along the Divide
Loveland, Abasin, Winter Park, Berthoud Pass

East of the Divide
Eldora, Echo, Rocky Mountain National Park, Cameron Pass

Central Mountains
Aspen, Sunlight, Monarch, Crested Butte, Irwin, Powderhorn

Southern Mountains
Telluride, Silverton – north side of the southern mountains | Purgatory, Wolf Creek – south side of the southern mountains