Summary

Sunday's cold front dropped temperatures 10-20°F and readings were low enough that Arapahoe Basin fired up their snow guns. The atmosphere also delivered a dusting of snow to the eastern foothills. But we'll head back toward warm and dry weather for most of the next two weeks, with the next chance for a storm around October 12th to 18th.

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Short Term Forecast

Last week we talked about how a cold front on Sunday would push temperatures down by 10-20°F and that happened as expected.

The green and blue colors on the map below show how Monday morning's temperatures were much cooler than Sunday morning's temperatures.

On Sunday night into Monday morning, temperatures at Arapahoe Basin fell to about 16°F at mid-mountain, so the crew fired up the snow guns.

With the forecast for the next two weeks showing a swing back to warmer weather, snowmaking weather will be marginal at best, so my guess is that this is more of a 'test the system' snowmaking run rather than the start of a sustained push.

Elsewhere along the eastern mountains of Colorado, snow also fell on Sunday night, and this snow was produced by the atmosphere rather than machines.

La Veta Pass in southeastern Colorado saw a dusting of snow at around 9,000 feet.

Snow showers and low clouds are still hanging around the southeast mountains now on Monday morning, including at La Veta Pass, while the satellite image shows the rest of Colorado enjoying gorgeous clear skies.

Sunday's cold front and Sunday night's cold temperatures and light snow will be about as exciting as the weather will get this week.

The forecast for the upcoming week is for dry weather and a return to average to above-average temperatures for most of Colorado. The only wrinkle in this will be a push of cooler air over the eastern plains on Thursday with temperatures dropping by 5-10°F compared to Wednesday's readings.

Extended Forecast

Let's look for our next chance of cooler weather and snow.

Last week, NOAA updated the American GFS model to forecast conditions out to 35 days into the future. We should never trust the details of a 35-day forecast, but if we average together multiple versions of the forecast and see a significant trend, that's something we can pay attention to.

So here is the forecast for the next three weeks, averaged from multiple versions of the new American GFS model.

This week, September 28th to October 4th, the western United States will see a large area of high pressure (red colors and black lines arcing upwards to the north). This is a dry and warm weather pattern.

Next week, October 5th to October 11th, the western United States will likely continue to see a large area of high pressure (red colors and black lines arcing upwards to the north). This means that odds are pretty high that we'll continue with the generally warm and dry weather.

Finally, three weeks ahead, between October 12th to October 18th, odds are for the weather pattern to change over the western United States (white color and black lines oriented west-to-east). This is when there will be a higher chance for a colder storm to move into the western United States.

The takeaway is that the next two weeks should be mostly dry and warm and odds show that the next chance for snow and/or cooler weather could be between October 12-18.

I have also looked at the European long-range model and it generally agrees with the forecast images I show above.

Until our potential weather shake-up around the middle of October, let's enjoy the relative warmth and extended delightful autumn weather. And please, no fires! Our ground is dry and fire danger will remain very high until we see significant snow cover develop later this month or or in November.

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!

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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