AccuWeather map, 11/10/21.
SIOUX FALLS, S.D. (KELO.com) — Autumn has largely held its ground across much of the eastern United States and Canada, with only fleeting glimpses of winterlike weather in recent weeks. AccuWeather forecasters say that is all about to change as a large snowstorm develops and targets portions of the north-central U.S. and south-central Canada.
The weather setup started to unfold Tuesday as a storm bringing another dose of heavy rain and mountain snow to California sped inland across the West. By Wednesday the energy from the system will shift eastward into the Plains, and a large storm will begin to take shape across the region. As the expansive storm triggers severe thunderstorms farther south, it will turn wintry farther north.
A cold rain will spread across the Midwest, northern Plains and southern Canadian Prairies Wednesday, with widespread temperatures ranging from the mid-30s F to the upper 40s (single digits above zero Celsius). However, as the storm gains strength later Wednesday, it will tap into colder air and drag it southward, causing rain to change to snow. The change will first occur across southern portions of Saskatchewan, Manitoba and southwestern Ontario Wednesday night. Snow will then expand into portions of the Dakotas and Minnesota by Thursday.
As the center of the storm slides northeastward into the Upper Midwest Thursday, it will slow down and even stall near Lake Superior. This will direct prolonged heavy snow toward portions of southwestern Ontario and southern Manitoba. In these areas, more than a foot (30 cm) of snowfall is expected, with an AccuWeather Local StormMax™ of 30 inches (76 cm).
The snowstorm can cause long-lasting travel disruptions in places like Thunder Bay, Ontario, and Winnipeg, Manitoba. Treacherous travel is also likely along the Trans-Canada Highway cutting through southwestern Ontario into southern Manitoba.
Winnipeg has yet to record measurable snow this season, making this autumn the first time since 2016 it has taken until November for the city to receive the first measurable snow, which is 0.1 of an inch or greater. Last year, Winnipeg recorded its first measurable snow on Oct. 16 and had already recorded six days with measurable snow by Nov. 10.
Lighter snow will eventually swing southward around the storm spinning near Lake Superior, reaching the U.S. by Wednesday night and Thursday. While the snow is expected to be lighter in intensity south of the U.S. and Canada border, the wintry precipitation can persist from Thursday through much of Friday, allowing the potential for several inches of snow to pile up over the course of a couple of days. In Fargo and Grand Forks, North Dakota, 3-6 inches of snow is expected from Thursday through Friday.
Snow showers may also stretch into parts of Wisconsin and Iowa by later Friday, with a slushy coating possible in some spots as well. Should Minneapolis receive more than a coating of snow, it would also be the city’s first measurable snowfall of the season. On average, the first measurable snowfall arrives in Minneapolis on Nov. 4.
Strong winds will also develop around the storm, helping to draw the colder air southward from Canada as well as creating blowing and drifting of snow. Even where snow accumulations are lower, even just an inch or two, wind gusts of 40-50 mph can cause extensive blowing snow and even blizzard conditions in open areas from Thursday into Friday.
“In areas that feel the brunt of the storm, these strong winds combined with any snow could cause extensive disruptions,” said AccuWeather Meteorologist Jessica Storm. Significant travel delays can occur across portions of major U.S. routes, such as I-90, I-94 and I-25, despite lower snowfall totals than north of the border.
Just a couple of inches of snow combined with strong winds can create extensive blowing of snow, low visibility and snow-covered roads.
Even in areas that receive no snow, strong winds will still sweep southeastward through the Midwest and cause disruptions and localized damage. Wind gusts of 30-50 mph, with an AccuWeather Local StormMax™ of 70 mph are possible all the way from Bismarck, North Dakota, to places like Kansas City, St. Louis, Chicago and Springfield, Illinois. This can lead to dangerous crosswinds for high-profile vehicles, as well as localized downed trees and power lines.
Even as the storm winds down in the Plains by the weekend, the push of wintry weather will keep advancing. A significant lake-effect snow event will likely get underway late this week as the rush of cold air advances eastward. And the hits from Old Man Winter won’t stop there. Another storm system can bring more widespread accumulating snow through the Midwest into the Northeast at the end of the weekend, followed by a shot of even colder air.
(By AccuWeather meteorologist, contributed this report.)
