Wednesday, Thursday, Friday, Saturday

The forecast is easy. Mostly sunny, warm, and dry. The only wrinkle will be stronger and gusty winds on Saturday afternoon through the evening.

This forecast is great for outdoor adventures for most of the state, and bad for wildfire growth and smoke, which will cover areas near the Colorado/Wyoming border and across some of the northern mountains and the northern front range. To see a high-resolution map of the smoke forecast for the next 18 hours, updated hourly, head over to our OpenSummit.com website and mobile apps.

Sunday, Monday, Tuesday

The cooler air will arrive late on Saturday night or on Sunday morning. Our best chance for snow will be from Sunday afternoon through Monday midday, though depending on the model, snow showers could stick around through Tuesday.

Temperatures will be cold enough for snow to accumulate down to 9,000 feet, and perhaps lower. These cold temperatures will also allow some mountains to make snow for at least a few days.

How much snow? It depends on which model you like.

Below are the snow forecasts from four models, ordered from least snow to most snow.

The American GFS model has trended toward a storm that almost entirely misses us to the north and brings just a few inches to the northern mountains.

The German ICON model is only slightly more optimistic with 1-5 inches for the northern and central mountains.

The Canadian GDPS model is more excited. It brings the storm in a little stronger and a little farther to the south, tracking directly through Colorado and dropping 5-10 inches on many mountains.

And the European ECMWF model is the most excited with a strong storm and double-digit totals for most mountain areas.

For the weather nerds out there (yes, that's YOU, because you're reading a detailed snow forecast in early October:-), you might be surprised to see me post the ECMWF forecast model. While the US and many governments have been providing their weather model data for free for decades, the ECMWF, which is a consortium of many European countries, has been charging hundreds of thousands of dollars for their data and maps and restricted sharing of those data and maps. Today, the ECMWF announced that access to and sharing of their maps is now free which is awesome news and should give us the ability to share ECMWF forecast maps. While the ECMWF forecasts are on average the most accurate forecasts, that doesn't mean that they are the most accurate forecast for each storm. But I look at these maps every day and I am excited to be able to share them with you!

Back to the forecast…which model should we believe? That's not really a great question because there is no way to provide a scientifically-supported answer. The best we can do is to look at the range of possibilities and average them out.

This chart does that, at least for the drier American GFS model and the snowier Canadian GDPS model. Like yesterday, it shows that the best chances are for 1-5 inches of snow over the northern mountains, with a few higher outliers.

The data that we present here on OpenSnow average together a few forecast versions and I am happy to see that the numbers below are reasonable – they show the chance for snow, but don't get us overly excited in case the lower-end scenarios pan out.

The 10-day detailed forecast comparison above, for Colorado, is available here on our website and you can also see it on our iOS and Android apps by going to Search > By Country, State & Region > United States > Colorado and selecting the "10-Day Forecast" tab.

To recap, expect colder temperatures on Sunday, Monday, and likely Tuesday as well. Our best time for snow will be Sunday afternoon, Sunday night, and Monday, and the best region for snow will likely be the northern half of Colorado where 1-5 inches is possible.

To get a sense of what might happen for the longer-range forecast out to 15 days, we can look at something called the Pacific North American Index (PNA).

If the PNA is positive, chances are we'll see drier weather.

If the PNA is negative, chances are we'll see stormier weather.

Below is the PNA forecast from today through October 23rd from the American GFS model.

• The black line shows a single forecast.
• The green line shows the average forecast from 31 model versions.
• The blue bars show the range of the forecast from 31 model versions.

The storm on Sunday into Monday is nicely shown where the lines dip down into negative territory.

Looking farther into the future, it appears that there's a chance for a storm around Thursday, October 15th, though the average of the models is not excited about this storm. From what I see on other charts, the most likely scenario on October 15th is for cooler air but likely not much or any precipitation.

And then looking into the third week of October, the green line and blue bars generally stay positive, signaling that the probability is for drier weather.

Of course, 10+ day forecasts can and will change, but this is what I'm seeing now.

Earn It

My son just turned three and there have been some toddler milestones over the last few months. Potty training. Riding a Stryder bike. Hiking to the top of a mountain (1.8mi, 750ft, woohoo!). For these and other feats, we encouraged him with a small toy that he would get if he completed the task. These rewards kept him motivated when the going got tough.

Occasionally, like most children, he became impatient when the going got tough and wanted to get the toy before he completed the task. In response, my wife and I calmly explained that the toy was something that he had to earn. He had to earn it. It wasn't just given to him. 

After we repeated the "earn it" mantra a few times, he got it. And he was so proud when, eventually, he completed his goals and earned his reward. He told all of his friends that he earned it. He was thrilled that his hard work paid off, and as parents, we were thrilled as well.

Relating to OpenSnow and the Colorado Daily Snow, here's my goal: I want to earn your subscription dollars this season.

I hope my daily forecasts for the past 10 years and the work of our team to develop our website, iOS, and Android apps have shown you how much we care about the weather, about snow, about the ski industry, and about creating innovative new features and views to help you find the best snow. Literally every day, I write down notes about how we can improve what we do. What we've done already, including local forecasters and comparison views across many ski areas, are things that you cannot find in any other weather app.

Most people that read the Colorado Daily Snow and that use our website and apps do so without paying us.

From a business perspective, keeping most features on OpenSnow freely available has worked thanks to the 100 advertisers that pay us each season to promote their product and service. I still remember how excited I was over 10 years ago when Copper Mountain and Hestra were the first to reach out to me to support a young snow forecaster.

While we will continue to welcome and be super appreciative of companies supporting us and keeping some of OpenSnow and OpenSummit free to check out, the simple math is that for us to provide the best real-time and forecasting data here in Colorado and worldwide, and to continue to invest for years into the future, we need to earn more subscription sign-ups. Acquiring, adjusting, and displaying a lot of weather and snow data is complex and requires a skilled team.

What you can do:

• If you're an All-Access subscriber, thank you, and tell your friends to sign up.
• If you're not a subscriber and you think we've earned your subscription, sign up now for $19/yr.
• If you're not a subscriber and we haven't earned your subscription, tell us how we can earn it.

How we are improving:

• So many maps. Some are on iOS, coming to Android and web soon.
• Providing easy access to avalanche forecasts.
• Worldwide coverage with hourly forecasts.
• Worldwide coverage with 10-day forecasts.
• Worldwide coverage with 30-day outlooks.
• Super High-Resolution forecast models for popular ski regions.
• And a lot more.

Our approach to the business:

• We are owned by ourselves. We do not have big-company pressure to grow.
• We want to grow so that we can hire the best people so that they can develop the best features.
• We are super conservative financially because bad things can and do happen (eg. COVID).
• Unlike other ski publishers that just shut down (OnTheSnow.com, Powder Magazine), we are not in danger of shutting down.
• We want to earn your subscription dollars because those dollars keep us profitable and focused on innovation.
• We will not beg for money to keep the lights on. This is a for-profit business. We want to work really hard to provide a product that will earn your money because we provide something that is unique, easy-to-use, and helps you to find your best days of the winter (and summer).

If you are one of the people that read the Colorado Daily Snow most days, and if my work has earned your trust and brought you a few (or many) insanely fun days in the snow, please take the next 2 minutes to subscribe. The list of what you get as an All-Access subscriber is here. 

Lastly, our pricing is going to change in a few weeks, so signing up now for $19/year will lock in that lower rate.

Thanks so much for allowing me and my team to earn your support!

And thanks for reading!

JOEL GRATZ

PS – Join me for a virtual talk on October 15th. I'll cover the forecast for the season and lots of other (fun) weather geekery. You'll also have the chance to win real-life prizes. This is all hosted by Neptune Mountaineering in Boulder! Details and tickets here!

Geography Key

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

Along the Divide
Loveland, Arapahoe Basin, 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