Colorado Daily Snow

Significant snow on Thursday then VERY cold temperatures through Saturday morning

Summary

Monday, Tuesday, and Wednesday will be dry and warm. Then a strong storm will arrive on Wednesday night and bring snow through Thursday night. Accumulations in the central and northern mountains should be in the 2-10 inch range, and temperatures could drop to near 0F at elevations above 10,000 feet on Thursday and Friday night. After this storm, we’ll see a slow warm-up and I do not know when we’ll have the next chance for snow.

Short Term Forecast

As of Sunday, October 6, the only natural snow on the ground across the western United States and Canada is confined to the higher elevations of British Columbia, Alberta, Idaho, Montana, and Wyoming.

Here in Colorado, there is machine-made snow starting to provide a bit of cover on a few runs, but there is no natural snow on the ground. That’s going to change thanks to the storm coming on Thursday.

Storm Ingredients

The most important ingredient for Thursday's storm is that the system will make a near direct hit on northern and central Colorado.

A few days ago, we weren’t sure if this storm would stay to our north and graze Colorado, or drop farther south and make a direct hit. Now that the system is ~4 days away, we can trust the model consensus which is showing a direct hit on the northern 2/3rds of Colorado.

A secondary but still important ingredient for snowfall is the jet stream, which will be over Colorado on Thursday. The jet stream is an area of fast-moving air at about 30,000 feet (the cruise elevation for commercial aircraft).

When the jet stream is overhead, it helps to lift the air below it, and rising air is what creates precipitation. The jet stream often creates narrow bands of very intense precipitation. We care about this because snowfall rates can be greater than one inch per hour, which is the threshold between "snowing pretty nicely" and "it's totally dumping/nuking snow".

When will the storm hit, and how much snow will fall?

Wednesday night is when the snow will begin in the far northern mountains, and then nearly all mountains and the cities around Denver should see snow through the day on Thursday. The snow will end on Thursday night.

Snow amounts should be 2-10 inches with the greatest amounts in the northern and northeastern mountains. The map below shows a model average. I think that amounts will be greater than what this map shows because cold temperatures will create fluffy snow (which can lead to deeper accumulations) and the narrow bands of intense snow created by the jet stream could also inflate totals.

Even with the caveat that this map is likely under-forecasting the storm, I am showing the graphic above because it provides a pretty good idea of the region favored for snow. And this region includes valley bottoms and the cities around Denver. We’ll see snow everywhere, not just the mountains! If you're driving on Thursday, roads should be covered in snow, especially later in the day and Thursday night when the coldest air arrives.

I mentioned that the map above looks a little low to me, but the blend of forecast data that we show on OpenSnow looks pretty good.

Notice that you can compare forecasts across mountains in a Summary, Graph, or Table view. Also, all three of these views are available on all three platforms – our desktop website, our mobile website, and on the latest version of our mobile app for iPhone (the update for Android will likely arrive within the week). If you’re not seeing the comparative view options on our iPhone app, please update to the latest version.

Also, if a list view isn’t your thing, switch to the map view and customize the data that you see. You can switch between 1, 5, and 10-day forecasts, as well as see reported snow, and view to different regions.

I am promoting these features on our website and apps because I find that a lot of people do not know that they exist. Also, if you have ideas for how to make these features better, email me ([email protected]) and I’ll let you know if your ideas are already on our list, something we should do, or something that we can’t do for a certain reason.

It’s going to be VERY cold

The snow that we’ll receive from this storm won’t create a true powder day (unless you can find a slope with short grass and no rocks), so the actual big story will be very cold air. This cold air may set some records.

At mountain elevation, we could see nighttime lows near 0F on Friday morning and again on Saturday morning.

And in the cities around Denver, prepare for low temperatures around 20F.

Friday morning is going to look and feel like winter. There will be fresh, fluffy snow on the ground, temperatures will be cold, skies will be a deep blue over many areas, and the higher peaks of central and northern Colorado will see lingering low clouds in the morning which should give way to beautiful sunshine by midday (unless a little wave of energy and moisture pushes through on Friday, then some clouds will hang over the mountains).

In short, Thursday and Friday are going to feel awesome, and after a 3.5-month break, it’s good to be talking about a snowstorm once again. The last storm was on June 21st, the summer solstice.

Extended Forecast

As you see in the temperature forecast above, after the Thursday storm, we’ll slowly warm up through next weekend.

After that, I do not have confidence in when we'll see our next chance of a significant storm. The best I can do is say that all models are hinting at something around October 20-22nd. That’s a long way out, so the forecast is unlikely to verify, and also, maybe something will pop up between the Thursday storm and the potential storminess around October 20-22.

I say this every year, and I’ll keep saying it – there is no correlation that I’ve found between early-season snow and snowfall during the rest of the season. I like to talk about storms, but I do not allow these early-season systems to set my expectations for a great season or a poor season. We’ll take each storm as it comes.

I’ll update each day this week because it’s going to snow and I am excited:-)

Thanks for reading!

JOEL GRATZ

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