A substantial snowstorm is poised to unload hefty accumulations over parts of the Plains and Midwest late this week and early this weekend, and it won't stop there. AccuWeather forecasters warn that it will likely go on to bring snow and ice, leading to the potential for dangerous travel conditions, across parts of the Southeast -- including as far south as Atlanta, which hasn't seen measurable snowfall in just about four years.
The storm will be what meteorologists refer to as a "Saskatchewan screamer" rather than an "Alberta clipper," AccuWeather Meteorologist Matt Benz explained.
The storm is forecast to dive nearly due south from the Saskatchewan province of Canada, hence the nickname, instead of the more traditional starting point in Alberta, Canada. Storms that originate from western Canada tend to move fast and have limited moisture available. Sometimes, though, high-ratio snow can unfold where a mere few tenths of an inch of moisture can yield 6-12 inches of snow.
Winter storm watches have been issued from late Thursday night through Friday for northeastern South Dakota, southwestern Minnesota and northwestern Iowa due to the predicted heavy snowfall. These watches are likely to expand to surrounding areas over the next 24 hours.
A southward dip in the jet stream will play a role in the storm's path due in part to another system that will unleash blizzard conditions across Atlantic Canada. After aiming for the northern Plains Thursday night and Friday, the storm is likely to take a more southern route than is typical for this type of weather system. It will take a nearly north-to-south path over the Plains and part of the Mississippi Valley from Friday to Saturday.
"There will be a band of heavy snow that generally extends from the eastern Dakotas and Minnesota southward to at least much of Missouri and maybe the Ozarks in Arkansas, if the storm can get far enough south before it begins to turn eastward," Mr. Benz said.
The snowy eastern and northern sides of the storm will bring enough snow to shovel and plow to cities such as Fargo, North Dakota; Sioux Falls, South Dakota; Minneapolis; Des Moines, Iowa; Omaha, Nebraska; St. Louis and Kansas City, Missouri, to end the week. People living in these cities or planning on traveling through should anticipate delays on the highways and at the airports.
A wide swath of 6-12 inches of snowfall is expected to encompass the eastern Dakotas to western Minnesota and Iowa. Within this area, the AccuWeather Local StormMax™ of 15 inches is most likely to occur.
St. Louis has been in a snow hole so far this winter. Except for 0.1 of an inch of snow that fell on Jan. 2, St. Louis has missed out on accumulating snow. The city typically receives about 17 inches of snow during the winter season and is likely to receive enough snow to shovel and plow with the impending storm.
Outside of areas predicted to experience lake-effect snowfall, there will likely be a sharp eastern edge of the heavy snow around the upper Mississippi River Valley. It is possible that Chicago, Milwaukee and Indianapolis receive little to no snowfall with this event, should the center of the storm track through the Dakotas. The difference between a plowable and disruptive snowfall and a nuisance coating in some locations could be determined by a storm track shift of 50 miles or less.
"While there may not be a great deal of wind ahead of and in the wake of the storm, it is likely to be quite windy where snow is falling with the system," Mr. Benz said. Winds during the storm can average 15-25 mph with gusts to 40 mph, which can lead to blowing and drifting snow and poor visibility.
Instead of a major push of Arctic air in the wake of the storm, temperatures may only dip slightly over much of the Central states this weekend. Highs Saturday are forecast to be in the teens and 20s F over the northern Plains and Upper Midwest. That will pale in comparison to the bitter air from early this week when temperatures failed to reach zero over parts of the northern tier Monday. Meanwhile, in a large part of the Southeast, temperatures will be low enough for wintry precipitation to occur for at least a portion of the storm.
There is the potential for a few inches of snow in cities such as Nashville, Tennessee, and Lexington, Kentucky. After last week's storm dumped heavy snow, both cities have already picked up more than their average seasonal snowfall to date with nearly 8 inches in Nashville and close to 10 inches in Lexington.
Enough snow to make surfaces slick is also possible around Little Rock, Arkansas, Tupelo, Mississippi, and Birmingham, Alabama.
"Cold air could make for a wintry mess for many, regardless of the intensity of the precipitation," Mr. Benz said, referring to those expected to be impacted across the southern U.S. from Arkansas to the Carolinas and Virginia.
The track and strength of the storm will dictate snow accumulations and where an icy mix will develop in the northern parts of Mississippi, Alabama and Georgia, and a large part of the Carolinas and Virginia.
Even a small amount of snow and/or ice can lead to dangerous travel from the Interstate 20 corridor northward to I-64. There is the potential for at least a small amount of snow and/or wintry mix in Huntsville, Alabama; Atlanta; Greenville, South Carolina; Charlotte, North Carolina, and Richmond, Virginia, from Saturday night to Sunday.
The last time Atlanta officially received accumulating snow was during the winter of 2017-2018, when storms in December and January each brought between 2 and 3 inches of snow.
People who live in or plan on traveling through the area are being urged by meteorologists to closely monitor forecasts that will likely be adjusted in the coming days.
There is some indication that the storm's forward speed may slow substantially while it pivots across the Southeast this weekend. This deceleration might allow the storm to gain strength and pull in more moisture, which could result in a moderate or heavy wintry precipitation event.
"If all of the pieces come together perfectly on Sunday, snowfall amounts could exceed a foot from northern Georgia through portions of the Carolinas and Virginia as the storm strengthens," AccuWeather Meteorologist Randy Adkins said.
Forecasters are also keeping close watch on the southern side of the storm, where severe weather may be possible along the Gulf Coast over the weekend. Rain and thunderstorms in Tampa Sunday afternoon could throw a wrench in the NFL Wild Card game between the Philadelphia Eagles and the Tampa Bay Buccaneers scheduled for 1 p.m. EST.
The jury is still out as to the exact path of the storm beyond the South, but AccuWeather meteorologists are gaining confidence that the storm will make another turn, this time to the north, and impact much of the Eastern Seaboard early next week. This northward turn would open up the door for a major storm with heavy snow, mixed precipitation and high winds in the mid-Atlantic and New England from Sunday night to Monday.
The exact timing of that northward turn will determine whether a plowable snowfall is in the offing for the Interstate 95 corridor or if heavy snow will focus on the interior Northeast.