Weather forecasters are increasing their predictions for this weekend's snowfall, with 5 to 8 inches expected for many in Minnesota but up to 10 inches possible in areas of southern Minnesota. 

The light, fluffy snow that began falling in the metro area around 3 p.m. Saturday was a problem enough for drivers, leading to scores of spinouts and crashes around the Twin Cities as the snow intensified. Authorities warned drivers to either slow down or stay home.

The highest total reported to the National Weather Service was 4 inches just south of the Twin Cities, as of 10 p.m. But in the metro, 2.3 inches fell at the National Weather Service office in Chanhassen through midnight. Also, 2 inches fell at the Minneapolis-St. Paul International Airport, a record for Dec. 10, according to the Weather Service. St. Cloud and Eau Claire saw about a half-inch.

The narrow band of heavy snow prompted a winter storm warning for areas of southern Minnesota. In effect until 6 p.m. Sunday, the warning included Dakota and Scott counties in the metro area as well as areas along the Interstate 90 corridor.

That band along I-90 was expected to have rates of a half-inch per hour, leading to higher accumulations through 4 a.m. Sunday, the National Weather Service in La Crosse, Wis., advised.  

As of 8:40 p.m., the State Patrol reported 347 crashes and spinouts across the state, with 34 injuries. Of those crashes and spinouts, 267 were in the metro area, with 27 people hurt. None of the injuries was considered serious, the patrol said.

Meanwhile, a cold air mass was moving in from the North Pole. It was expected to bring the season’s first subzero temperatures to the metro area by Tuesday or Wednesday.

Because the air is so cold and dry, Saturday and Sunday’s snowfall won’t contain a lot of moisture, said Eric Ahasic, a meteorologist with the National Weather Service in Chanhassen.

“It will be that light, fluffy snow. It shouldn’t be too hard to shovel,” he said.

After the state’s unusually warm autumn, shifting weather patterns are bringing the season’s first polar air, heralding what’s expected to be a colder-than-usual winter, Ahasic said.

“Part of the reason we were so warm in the fall was, all that cold air in the arctic was kind of pushed to the other side of the world — to Siberia and northern Europe,” he said. “Just in the last few days, that pattern has slipped, and now that air is coming across the North Pole.

“For December, January and February, we’re looking at a good chance of being below normal for temperatures, and right around average for precipitation.”

The average snowfall in the Twin Cities area during meteorological winter (December through February) is 54 inches, he said.

Despite the warm autumn, the arrival of subzero temperatures isn’t far off the historic norm, Ahasic said. In the Twin Cities, the average date of the first subzero temperature is Dec. 8. The area is likely to see a low below zero on Tuesday or Wednesday, he said, only about a week later than average.