A potentially dangerous pre-Thanksgiving snowstorm is expected to arrive in South Dakota today, with parts of the southeast corner of the state expected to receive about a half-foot of snow.

An updated snowfall projection for the Mitchell area from the National Weather Service in Sioux Falls calls for 4 to 8 inches of snow, starting Tuesday morning and becoming heavier Tuesday afternoon and evening, with wind speeds expected to gust to 40 mph or more, leading to near-whiteout conditions and blowing and drifting snow.

The snow is expected to diminish early Wednesday morning, but it could cause some treacherous travel on a week where drivers are eager to visit family and friends with Thanksgiving on Thursday.

Higher snowfall totals are projected along the Missouri River and Nebraska border, calling for 7 to 12 inches of snow in Gregory and 6 to 9 inches of snow in the areas of southern Charles Mix, Bon Homme and Yankton counties.

NWS Sioux Falls’ Observing Program Leader Brad Adams said the heart of the system will be Tuesday and the snow is expected to pick up by mid-afternoon.

“We’re expecting accumulating snow throughout the night and we could have anywhere from 5 to 6 inches of snow in the Mitchell area and Davison County, and then definitely along the Missouri River 6 to 8 inches,” Adams said.

An area stretching from Chamberlain to Woonsocket and Huron and to north of Brookings is expected to be on the edge of the storm’s major impact areas, and the NWS says there’s a lower level of confidence in snow totals in that area. Chamberlain and Woonsocket are forecasted for as little as 2 inches of snow, but up to 7 inches on the high side.

With the major travel holiday on Thursday, Wednesday is traditionally a big day for people to be on the roads. Adams said the weather will be “between systems,” with a smaller snow threat on Thursday, as well.

“Roads will probably be in poor shape on Wednesday morning, and then get better in the afternoon and evening, so that might be the time to be on the roads if you’ve got somewhere to be,” Adams said. “There’s more snow building in on Thursday and the timing will probably be late morning, but we’re not expecting much, and again, higher totals along the Missouri River and an inch or so along Interstate 90.”

A white Thanksgiving, Adams said, is always a possibility when the November weather has a habit of changing quickly.

“It’s certainly common,” Adams said. “We’ll stay warm into November and then things can turn cold in a matter of a day or two.”

The snow has forced the cancellation of classes at Augustana University in Sioux Falls and on the University of South Dakota campuses in Vermillion and Sioux Falls. Dakota Wesleyan University’s Thanksgiving break was already underway, beginning Monday, with classes restarting at 8 a.m. Dec. 2.