The second snowstorm of the year is going to bring a bigger impact to southern Colorado than the first bout of snow did, as some of our local mountain communities may see more than a foot of snow.
Winter Storm Watches have been posted for Wednesday night and Thursday for the eastern mountains, from the foothills west of Denver to the New Mexico state line. The Palmer Divide and southern I-25 corridor are also included in the Winter Storm Watch. The confidence is high that these areas will see a moderate to heavy accumulation of snow with major winter travel impacts early Thursday.
The storm is approaching from the northwest. As it moves into Colorado Wednesday night, a jet streak on the back side of the storm may induce a circulation in the mid-levels of the atmosphere. Storm circulations are significant features of storms because they increase the vertical motion and the resultant moisture that falls. Over the last two days, most computer forecasting models have been converging on the idea that a circulation will develop over southern Colorado. This, along with several other important features, points to a heavier snow than the first storm of the season.
As you can see in the image above, which shows the expected snow from the same two computer models through 6 p.m. Thursday, the model with the circulation has heavier snow for more areas than the storm that doesn’t develop a circulation over southwest Colorado.
Every forecast contains elements of uncertainty. It’s our job as broadcast meteorologists to take the oftentimes ugliness of that uncertainty and provide an easy-to-understand forecast in a nice, clean package in three minutes on your television. Some of the most significant forecasting work behind the scenes involves dealing with the differences in the models, why they exist, how they are likely to change, and ultimately, what is the most likely outcome. It’s that most likely outcome that we present as our forecast.
Part of what we do is use a number of computer models to create probabilities that a certain amount of snow will fall. By doing this, we begin to take the uncertainty, the variability of the atmosphere and begin to hone in on what is the most likely scenario. Below, you see the probabilities of certain amounts of snow falling in Colorado Springs and Pueblo with the incoming storm.
So while we’re still working on it, and we’ll make the normal snowfall maps with ranges that we usually present in advance of storms, the above graphics “lift the curtain” a little into how we come up with these ranges behind the scenes. With where we sit Tuesday morning, here’s what I’m thinking as of now:
Palmer Divide: 3″-8″
Teller County: 6″-12″
Colorado Springs: 2″-5″
Cañon City: 2″-5″
Fremont County: 3″-8″
Pueblo: Trace – 3″
Wet Mountains: 6″-12″+
Sangre de Cristos: 6″-12″
Right now, it looks like the first of the showers could fall in the Pikes Peak region Wednesday afternoon. It seems most likely at this point that roads in and around Colorado Springs will remain okay through the evening commute, but if showers come in fast enough and the initial rain changes to snow fast enough, visibility could drop enough to cause a little bit of on impact over northern El Paso County and Teller County.
People driving home from Denver have a higher likelihood of being impacted as the snow moves in from the north. Roads appear most likely to just remain wet during the afternoon between Denver and Monument, but as the sun sets, roads may slush up under the heaviest showers.
The Thursday morning commute will be a slow one in the Pikes Peak region and up to Denver and Highway 50 west of Pueblo. The mountains southwest of Pueblo will still be getting heavy snow early Thursday and travel along I-25 south of Denver will be snow-packed too.