AccuWeather graphic, 12/28/20.
SIOUX FALLS, S.D. (KELO.com) — The end of the year is quickly approaching, but Mother Nature is set to bring one more winter storm to the center of the country.
A significant amount of ice and the potential for blizzard conditions can lead to dangerous travel before the door closes on 2020.
The first “real storm” of the season in the southwestern United States arrived late Sunday and will push inland through Monday night. The storm has already delivered the biggest single-storm rainfall in many areas since last spring and late-winter to parts of Southern California.
After bringing a fresh accumulation of snow to the Rocky Mountains through Monday night, the storm will move out over the Plains. The storm is then expected to strengthen and spread precipitation across the center of the country on Tuesday and Tuesday night.
As the storm strengthens, it will draw in moisture and more mild air from the Gulf of Mexico, which will fuel areas of heavier precipitation into the middle of the week.
In the south, any downpours can lead to flash flooding, mainly in low-lying and poor drainage areas, including around Kansas City, Oklahoma City and Dallas. In addition, some of the thunderstorms across the South Central states are likely to be heavy and gusty and eventually may produce severe weather as the week progresses.
As this mild air pushes north, it will run into much-colder air that has settled over the central and northern Plains, which will cause precipitation to transition into an icy mix.
Cities that may fall in this icy zone include Omaha, Nebraska, Des Moines, Iowa, and even Madison, Wisconsin. Any untreated surfaces in this area can become slippery throughout the day.
Ice that accrues over 0.25 of an inch, is most likely to occur across southeast Nebraska, northeast Kansas, northern Missouri and southern Iowa. This ice can weigh down tree branches and power lines, which can lead to localized power outages.
Areas on the southern side of the icy mix, including Chicago, may have precipitation start as an a brief period of accumulating snow or an icy mix before changing over to rain into Tuesday night.
Even colder air to the north will allow for precipitation to fall as mostly snow from northern Kansas and Nebraska to Wisconsin and Michigan.
In just 24 hours, snowfall totals can reach 6-12 inches, including cities such as Rochester, Minnesota; Cedar Falls, Iowa, and Green Bay, Wisconsin. It will be in this band of heavy snowfall where the potential for the AccuWeather Local StormMax™ of 20 inches to occur.
Snowfall totals of 3-6 inches are expected from the eastern Dakotas to northern Michigan. A general 1-3 inches of snow is expected across the rest of the Midwest.
Exact totals on the southern side of the snow may fluctuate if more or less milder air moves over the region during the duration of the storm.
In addition to heavy snow, as the storm strengthens, wind speeds will also increase. The combination of these two factors may ultimately lead to near-blizzard conditions in some areas.
A blizzard is defined as a storm that brings sustained winds of 35 mph or greater and visibility less than one-quarter of a mile for three consecutive hours.
Major highways may once again be shut down across the region during the height of the storm, including long stretches of interstates 29, 70, 80, 90 and 94. People that must travel should make sure to pack emergency supplies in case they become stuck on a road shut down by snow or an accident.
Given the relatively flat terrain and lack of trees in portions of the Plains and Upper Midwest, some forecasters have nicknamed this zone of the country as “Blizzard Alley” during the winter months. Prior to the Christmas holiday, the Red River Valley in the Dakotas and Minnesota observed blizzard conditions as a powerful storm swept through the area, causing significant disruptions.
Minnesota state troopers helping to recover vehicles that were stranded off Highway 12 in Swift County, Minnesota, during blizzard conditions on Dec. 23, 2020. (Twitter/@MSPPIO_NW)
The storm will likely continue on across the Midwest Wednesday and into Thursday before widespread snow tapers off to lingering lake-effect snow showers. Upon departure from the Midwest, another round of winter weather for the Plains and potentially flooding rainfall across the Eastern Seaboard will be possible for New Years’ Eve.
( AccuWeather meteorologist, contributed this report.)
