Colorado Daily Snow

Heads up, there may be fresher snow! Read the latest Colorado Daily Snow

By Joel Gratz, Founding Meteorologist Posted 6 years ago September 22, 2017

Dry weather is done and high-elevation snow is likely through end of month

Summary

A slow-moving storm will bring showers on Friday and Saturday with snow levels near or above treeline, and then temperatures will cool on Sunday, Monday, and Tuesday with snow likely falling below 10,000 feet. Most mountains will receive 4-8 inches by the middle of next week, and it's possible that another storm will keep showers around Colorado through the end of September.

Short Term Forecast

Storm #4

Our fourth storm of the season is a sloooooooow mover. Expect showers through at least Tuesday, September 26th.

As of Friday morning, the storm is spinning over central Idaho.

Zooming into Colorado, the Friday morning radar shows a few showers over the southern mountains.

Webcams in the south corroborate the radar.

Telluride is waking up to higher elevation rain and snow showers (shown as the white fuzzy look in the upper-right part of the image).

Across the peaks and over in Silverton, looking north, it's the same story. That white fuzzy look near the top-right of the image is high-elevation rain and snow showers. And, check out the colors of those Aspens!

Friday and Saturday

Expect on-and-off showers both days with a snow level at or above treeline (roughly 11,000 feet). Temperatures will NOT be very cold during the early part of this storm.

Sunday through Tuesday

This is the cooler part of the storm. Snow levels should gradually drop to about 9,000 feet, ish. Any heavier shower can push snow levels even lower in elevation.

Showers?

It's unlikely that there will be one period of steady precipitation during the next five days. Instead, the storm will create times of showers, and these will be followed by times of dry weather and some sunshine.

Snowfall

Since we'll see showers versus steady precipitation, forecasting snowfall accumulation is tough. Any single heavier shower can drop 1-2 inches per hour and the snow line could push down to 9,000 feet or lower. Light showers would drop much less snow will a snow line around 10,000-11,000 feet.

With this variability in mind, it's best to look at ensemble forecasts. The ensemble forecasts below show the average of 51 versions of the European weather model. Averaging 51 versions of a model usually results in a more accurate forecast than looking at a single version of a model.

First, the snow forecast for Silverton. The green bars show the average of 51 models, which is 14 inches. That's a pretty high average, so my confidence in significant snow above treeline in the southern mountains is rather high. However, the blue bar is the forecast from just one of the versions, which is about 6 inches. So, plenty of uncertainty.

Below is the snow forecast for Berthoud Pass in the northern mountains. The model average (green bars) is about 5 inches, while the blue bar, showing one version of the model, is predicting 11 inches. Again, lots of uncertainty.

Ugh, uncertainty

Yup, that's the name of the game with slow-moving storms. Bottom line – expect snow near and above treeline for all mountains, with 4-8 inches likely by Tuesday and perhaps a foot or more, especially in the southern mountains.

Extended Forecast

Previously, I thought we'd return to dry and warmer weather during the last few days of September, once Storm #4 moves away.

However, the latest models show that our slow-moving Storm #4 will spawn a child, and this child storm will hang out over the southwest through most of the rest of September. Here is the precipitation outlook for late September and early October.

It's possible that there will be showers and snow in Colorado each day from now (Sep 22) through the end of September. I'll keep you updated!

Thanks for reading and have a great weekend!

JOEL GRATZ

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About Our Forecaster

Joel Gratz

Founding Meteorologist

Joel Gratz is the Founding Meteorologist of OpenSnow and has lived in Boulder, Colorado since 2003. Before moving to Colorado, he spent his childhood as a (not very fast) ski racer in eastern Pennsylvania.

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