Since 2020, the Omaha area has had the extremes in winter. From 2020-2021, the region saw one of its snowiest years on record with over 48" of snowfall. Then we reversed that in 2021-2022 with one of our least snowy years on record with just 10.8" of snowfall. For those who remember the constant snow events of 2020-2021, perhaps one sticks out above the rest, January 25, 2021.
On that day, Omaha and the surrounding area were walloped with over 1' of snow in many locations, with a few spots near Lincoln seeing up to 16"! In this week's This Week in WX History, let's look back on the set-up that brought the perfect storm to the Omaha area.
THE SET-UP
Winter storms are complex, with many moving parts attributed to them. The atmosphere is a 3D space, where the workings from the top of the cloud to the surface influence the snow amount, precipitation type, and where the heaviest snow falls.
Many factors go into heavy snowfall production. The first, and arguably the most important, is moisture. You need moisture to produce clouds and in turn, produce snow. On January 25, we had moisture in abundance across Nebraska and Iowa for the generation of heavy snow. If you do not have moisture, you will not have snow.
Another major ingredient is upper-level lift, which is effectively a front that forces the air to rise. If you get enough air in a particular section of the atmosphere where snow development is the most efficient, you get heavy snowfall. On January 25, upper-level lift was particularly strong atop Omaha. A secondary ingredient in the upper-level lift is instability, the ability for air to rise faster into the atmosphere. Instability is most commonly used to forecast thunderstorms, but if instability exists in the atmosphere in the winter, heavy snowfall becomes possible. Thundersnow also becomes a possibility.
At the surface, the final ingredient is the surface low, where on January 25 the low moved from Oklahoma to Missouri. This track of the low is very favorable for snow in Omaha, as the northwest quadrant is the location where snow is most efficient. It is these ingredients that all stacked up over Omaha where heavy snow became apparent, where snowfall amounts ranged from 1-2" of snow PER HOUR!
THE FORECAST
The forecast for January 25 was tricky, as it was one of those "track of the low will be crucial to snowfall totals" types of storm. The potential for heavy snowfall was there, but where would the heaviest snowfall? In the days leading up to that Monday, the focus was along and south of I-80, where forecasted snowfall amounts were centered around Nebraska City.
However, the subtle shift in the ingredients mentioned above moved around 30-50 miles northward, placing the axis of heaviest snowfall along the I-80 corridor.
THE STORM
Snow began near the NE/KS state line during the morning and quickly moved northward towards I-80. For most of the day, Omaha and Lincoln saw heavy snowfall between 1-2" per hour. Snow piled up before it was all said and done. At KMTV, the weather team had to sleep at the station to continue coverage as roads became nearly impassable.
When it was all said and done, many locations in the metro picked up over 1' of snow. In the 24 hours from midnight January 15 to 12 am January 26, Eppley Airfield picked up 11.9" of snow. This is the 7th largest 24-hour snowfall since record-keeping began in 1871 in Omaha. In Lincoln, 14.5" of snow in that same period meant it was the 2nd highest 24-hour snowfall in Lincoln's history.
Elsewhere, over 1' of snow fell from central Nebraska through southwest Iowa. Nebraska City picked up 12.5", Red Oak up to 12.6", and Clarinda picked up 14".
