A large winter storm with the potential to dump a foot or more of snow is grinding its way toward Minnesota, and its arrival is likely to mess up travel plans, complicate last-minute errands and ensure a very white Christmas.

"It's not definite yet, but it has an uncanny resemblance to the East Coast storm last Saturday," meteorologist Paul Douglas posted Monday on his Facebook page. "I want to see one to two more computer runs, but this could be the snowiest Christmas for Minnesota in 30 years."

According to a winter storm warning issued this afternoon for central and southern Minnesota and western Wisconsin, the mess is expected to begin Wednesday afternoon -- and go on and on.

"This is major," said James McQuirter, meteorologist at the Twin Cities office of the National Weather Service. "It might not get out of here until Saturday."

Douglas said in an interview that, depending on the temperature, freezing rain, sleet and/or ice could enter the picture, particularly to the east and south. Either way, "I think travel conditions Christmas Eve and Christmas Day may be pretty bad," he said, encouraging people to leave earlier on Wednesday if they have that option.

Computer models have been "all over the map," he said, and snow totals approaching 2 feet are not out of the question, though it's "way too early to know" exactly where in Minnesota that would happen.

The heaviest snowfall, 12 to 20 inches, likely will fall in a swath from Minneapolis to the Iowa border and west to the South Dakota border, said National Weather Service forecaster Jim Taggart. Duluth and the eastern part of the state also could see 6 inches or more of snow. The northwest part of the state will probably get clipped with 3 to 4 inches of snow, Taggart said.

"There's no doubt that we'll get heavy and a significant amount of snow," he said. "The question is the timetable and the amounts. ... It's going to be wave after wave of snowfall."

Some flights into Minneapolis-St. Paul International Airport from the eastern U.S. and Canada were still running behind schedule Monday as eastern cities continue to clean up from the massive weekend storm, and airport spokeswoman Melissa Scovronski said airlines might begin tinkering with schedules as the new storm moves into the Midwest. She encouraged fliers or people picking up others at the airport to check with individual airlines for schedule changes.

Minnesota Department of Transportation spokesman Kevin Gutknecht said that with many people taking time off work for the holidays "it eliminates the rush hour, which is good." But he noted that people may be out driving more continuously.

McQuirter said that the Twin Cities has rarely seen a major storm on Christmas Eve or Christmas Day. The snowiest Christmas Eve in the Twin Cities was in 1932, when 3 inches fell. The snowiest Christmas Day was 1945, with 9.6 inches, part of 11.3 inches that fell over the two days. The 3.4 inches of picturesque, fluffy snow that fell on Christmas Day in 2007 was the most since 1950.

Getting home from school

The storm poses a particular challenge for college students hoping to travel home after final exams, the latest of which will take place on Wednesday afternoon at large schools such as the University of Minnesota in the Twin Cities and the University of Wisconsin-Madison.

"Obviously, the situation is not optimal when the semester backs up so closely to the Christmas holiday," said Daniel Wolter, news service director at the U of M. But because the State Fair is intertwined with the St. Paul campus, the school can't begin classes until after Labor Day, which this year was on Sept. 7.

"This year's situation was purely a result of the calendar," he said. "Last year, when Labor Day fell on the 1st of September, our semester ended on December 18th."

Many private institutions, such as the University of St. Thomas, have slightly shorter semesters and wrapped up their finals last week. But the last exams at UW-Madison begin at 2:45 Wednesday, by which time snow and gusty winds could be hampering travel to Minnesota.

That's making Lauren Belisle of St. Paul anxious that she might be forced to spend another night in Madison. "I'll be bummed," said the UW-Madison student. Her father is driving Wednesday from the Twin Cities to pick her up. "I just want to be home in my warm house with my family. ... We'll just have to make the best of it," she said. "Maybe my dad and I will go out to dinner and do something fun."

Jim Foti • 612-673-4491 Bill McAuliffe • 612-673-7646