The State of the Atmosphere: Sunday, December 22nd, 2019

For snow lovers, a disappointing outlook this Christmas week as no snow is expected across Eastern Colorado before the holiday. For travelers, a collective sigh of relief –– especially after many Thanksgiving holiday plans were thrown up in the air thanks to heavy snowfall along the Front Range just a few short weeks ago.

Instead of cold and snow to kick off the official start to winter this weekend, most of us spent the weekend enjoying warmth like we haven't seen in over a month. It looks like the high today maxed out at 67°F at Denver International Airport. A degree cooler than forecast, but as warm as it's been in Denver since early November:

As we covered in our outlook on Friday the week ahead will feature a gradual cooling trend as the ridge loosens its grip and a series of storms being to push in from the west.

Below is a look at the temperature forecast through Wednesday evening for Denver. Mid 60s again on Monday, mid 50s for Tuesday, then into the 40s for highs on Christmas Day. Not much precipitation is expected over the next three days, though a stray rain or snow shower over the plains by Tuesday night and Wednesday cannot be ruled out.

Our focus turns toward late this week and next weekend for our next potential weather maker. Right now this system looks to favor southern Colorado, but some rain and snow will be possible across Northern Colorado as well even if the track doesn't change all that much.

Operational model runs are all over the place. Some have a rather potent storm for Raton Pass and the Southeast Plains. Most keep the heaviest snow well south of the Denver area. A few bring a least a quick shot of snow to the Front Range.

The global ensembles are in better agreement, with most of theme showing a positively tilted trough digging through Southern California, Arizona, and New Mexico late this week and next weekend, but never really lining up for a big impact event across Eastern Colorado. Below is the latest European ensemble forecast, showing the trough (blues) moving pretty far south of Colorado early Saturday. The Canadian and American models look similar.

This would equate to some good snowfall across the Four Corners region, but less so across Northern Colorado (especially northeast). For Southern Colorado we seeing probabilities for 3" of snow or more next weekend in the 30%+ range, so something to watch over the next several days:

A quick look at the GEFS ensemble forecast for Denver shows a dry outlook most of this week, but turning more unsettled by the weekend. You'll also note a steady drop in temperatures over the next seven days (top red line), as ridging moves to the east:

If you're leaving in Northeast Colorado and hoping for a big snow to round out the month... I'd tell you there's a chance, but most likely it's not to be. The latest European ensemble forecast shows plenty of wet weather across the Southwest United States, perhaps even moving into Southern Colorado, but this particular model shows Northern Colorado ending the year below average for precipitation:

Again, enough activity nearby to keep an eye on things, but odds are with a more southerly bias to the next few systems set to move through.

We'll keep an eye on things. Enjoy your holiday week, and stay tuned!

Brendan Heberton

Brendan is founder of Weather5280. He is co-founder of FreshyMap, and develops software for geospatial data analysis and visualization.

Denver, Colorado
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