As Thanksgiving travelers prepare for their journeys home, they might find themselves facing a daunting challenge. A significant winter storm is set to sweep across half of the United States, potentially turning travel plans into a nightmare. Recent forecasts indicate that this fast-moving system is poised to unleash blizzard conditions over the Midwest before evolving into a prolonged lake-effect snow event around the Great Lakes and the Northeast. This formidable storm has been gaining momentum in the Central U.S. since mid-week, with meteorologists cautioning that its most severe impact will be felt from now through Sunday. More than a dozen states could experience continued snowfall into early next week.

The wintry onslaught threatens to deposit anywhere from several inches to three feet of snow in some regions, complicating post-Thanksgiving travel. This could lead to treacherous road conditions, reduced visibility, and extensive flight delays from Black Friday through at least Tuesday. AccuWeather meteorologist Elizabeth Danco has issued a stark warning: “Some highways may close due to the heavy snowfall rate and perhaps chain-reaction accidents.” Initially, the storm is expected to traverse eastward from the Midwest through Saturday, affecting Colorado, Wyoming, Montana, Kansas, Nebraska, Iowa, Minnesota, Wisconsin, Illinois, Indiana, Michigan, and the Dakotas with snow and substantial travel disruptions.

By Sunday, parts of Iowa, Minnesota, Wisconsin, Illinois, and Michigan could find themselves buried under up to 12 inches of snow, with AccuWeather suggesting that in some areas, totals could rise to 18 inches under extreme conditions. As the holiday weekend progresses, the storm is set to enter its lake-effect phase around the Great Lakes, with heavy snow bands extending into the Northeast and New England. This development is driven by the interaction of cold Canadian air and moisture from the Gulf Coast. States such as Ohio, Pennsylvania, West Virginia, New York, Connecticut, Rhode Island, Massachusetts, Vermont, New Hampshire, and Maine could see up to six inches of snow between Monday and Tuesday.

Meteorologists said this holiday snowstorm is acting like a speedy low-pressure system, often called a clipper, which formed over the the Plains and Rockies. It’s pulling in cold air down from Canada and moisture up from the Gulf, which has collided in the middle of the US to form a mix of rain and snow in the South, and heavy snow everywhere north of Missouri. This first part of the storm arrives over the Great Lakes around Michigan this weekend, and meteorologists said it will morph into a lake-effect storm system because of the Great Lakes’ ability to hold heat in the water.

The warm moisture from the lakes, combined with the cold air continuing to flow across the US will cause the storm to pump out large amounts of snow throughout the region, lingering in the Midwest for days while also leaking into the Northeast. Forecasters urged drivers planning to travel on Interstates 75, 79, 80, 81, 86, 90, and 196 to keep track of lake-effect and snow squall warnings. Drivers will also need to be prepared for sudden changes in road conditions during the storm and the possibility of stopping their trips if visibility drops.

The lake-effect portion of the storm this weekend could bring up to 36 inches of snow to parts of northern Michigan, northwestern Pennsylvania, and western New York, meteorologists explained. Director of forecasting operations Carl Erickson later said : ‘The period from Saturday to Saturday night is likely to be the worst for travel, considering that the snowstorm will be in progress over such a large area.’ AccuWeather supervisor of forecasting operations Alyson Hoegg added: ‘Downtown Cleveland is expected to experience heavy lake snow with enough to shovel and plow.’

AccuWeather vice president of forecast operations Dan DePodwin noted: ‘This will be the most widespread lake-effect snow event of the season so far.’ The National Weather Service has already issued winter storm warnings in Iowa, Montana, South Dakota, Nebraska , southern Minnesota, southern Wisconsin , and northern Illinois on Friday. This weekend’s winter blast has the potential to ground thousands of flights across the US, with the Federal Aviation Administration (FAA) likely to issue ground stops if snow and ice begins to build up on runways.

On Wednesday, 6,667 flights entering or leaving the US were delayed. Nearly 900 of those delays took place at Chicago O’Hare International Airport because of lake-effect snow hammering the upper Midwest all week. For travelers along the East Coast this weekend, AccuWeather warned rain and fog on Sunday will likely impact drivers along I-95, in cities such as New York, Philadelphia, and Atlanta. Boston, New York, and Philadelphia could also see snow and ice early next week, prolonging the post-Thanksgiving travel delays even further.