December 2020 was marred by a series of weak storm systems that resulted in very little snowfall. This lack of moisture further exacerbated the ongoing drought in Colorado and dashed the hopes of many for a white Christmas in our area. Overall, it was yet another warm and fairly dry month. In fact, this was the sixth month in a row that ended warmer and drier than normal. Here’s a quick and colorful rundown of our weather during December and how it relates to climatology.

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Top Weather Highlights of December 2020:

REX BLOCK PATTERN KICKED OFF THE MONTH: A stagnant pattern known as a “rex block” developed late in November and persisted into early December across the western United States. During this time period (Nov 26-Dec 10), no measurable precipitation occurred across the Denver Metro area exacerbating existing severe drought conditions.


A TALE OF TINY SNOWSTORMS: The weather gods were not in our favor in December with most if not all storms arriving to the Front Range half-baked. Either the track was unfavorable, the storm was too weak, or the large-scale system was moving too fast. In all cases, though, the amount of snow produced was meager leading to underwhelming snow totals for the month as a whole. Boulder recorded 9 days with snowfall which is above normal. However, those 9 days only amounted to 5.8″ of snow which is less than half of normal. Similarly, Denver reported 10 days with snow falling but only 7.0″ of total accumulation.

Visit our 2020-2021 Winter Snow Summary

EAST COAST NOR’EASTER: The biggest snowstorm in 10 to 20 years dumped more than 3 FEET of wet snow in several East Coast states from December 16th to 18th.

Some of the craziest snow totals came out of the Binghamton, NY area at more than 44 inches!

THUNDERSNOW (!) AND STRONG WINDS: On December 22nd a strong Pacific cold front blew from west to east across the entire state of Colorado. Very cold air aloft fueled convective snow showers across the Mountains prompting a handful of Snow Squall Warnings to be issued. The most intense wintry cell near Steamboat Springs produced more than a dozen lightning strikes and a visibly horrifying snow squall line.

Across the lower elevations, the convective snow showers largely dissipated but the winds remained with gusts accompanying the frontal passage blowing in excess of 70 MPH. The highest gust on the Plains was 92 MPH in west Arvada at the normally very gusty intersection of Highway 72 and Highway 93.

A BROWN CHRISTMAS: Despite Boulder’s climatology painting Christmas Day as the most likely to have snow on the ground, 2020 failed to deliver notching the warmest Christmas temperature in 15 years. Skies were completely sunny and the ground was largely snow-free.

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December 2020 Recap Graphics:

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