Prepare for just about anything to fall from the sky this weekend — in terms of precipitation, that is. A storm headed toward Minnesota, beginning just after midnight early Saturday, is expected to bring some combination of snow, sleet and rain, but which will go where is still uncertain, especially around the Twin Cities.

On Friday, Delta Air Lines offered a travel waiver for changes to flights for those traveling on Saturday and Sunday through some airports in the Upper Midwest. The airline is encouraging passengers to track weather and flight changes closely. The airports covered by the waiver include Minneapolis-St. Paul Airport and others in Minnesota, South Dakota and North Dakota.

“At this point, all precipitation types are on the table,” said Tyler Hasenstein, meteorologist with the National Weather Service in Chanhassen. “The scenario right now is still rather complicated. There’s quite a bit of uncertainty regarding it and it’s likely to change.”

According to forecasts so far, the western border of Minnesota will get snow, while precipitation in areas south and east of Alexandria, Minn., will likely be at least partly liquid — sleet or freezing rain or just plain rain. As it freezes, the concoction could leave roads, trees and power lines coated with slick and heavy ice.

The Minnesota Department of Transportation (MnDOT) is advising travelers to keep a close eye on road conditions along their routes, spokeswoman Anne Meyer said. MnDOT’s website offers detailed information about road conditions, including camera views of roads around the state.

“Really be weather aware; a lot’s going to change in next 48 hours,” Meyer said. “Slick spots in general are going to be worrisome.”

Winds will be relatively mild at about 10 mph, Hasenstein said. That’s good news, because wind can make road conditions particularly treacherous in open areas outside the Twin Cities.

Strong winds are also a threat to power lines, especially when lines and nearby trees get coated with heavy snow or ice, said Chris Ouellette, a spokeswoman for Xcel Energy. Damage is most likely to occur “if the winds pick up and start to move the extra weight around.” Xcel stations deploy extra crews in areas where conditions threaten potential power outages, she said.

Rain in December is not particularly unusual, Hasenstein said. In fact, about an inch of rain, along with about half an inch of snow, fell on the Twin Cities exactly a year ago, on Dec. 27, 2018.

Still, last winter was unusual overall, said Peter Boulay, assistant state climatologist.

“Last December wound up 6 degrees above normal — a balmy December,” he said. “Then everything changed and then we had winter.”

Winter more than made up for lost time. Overall snowfall of 72.8 inches from December through April was nearly 2.5 feet higher than average. In February alone, 39 inches fell, breaking the month’s previous snowfall record (26.5 inches in 1962) by more than a foot.

Most years, though, snowfalls have been about average lately. What has changed is that not as much remains piled on the ground, Boulay said. If you grew up here and remember trudging to school through much deeper snow, it’s not entirely because you were shorter back then. “We just don’t keep it on the ground like we used to,” he said.