April snow showers will bring “hazardous or impossible” driving conditions this week.

The National Weather Service issued an alert early Tuesday morning warning of an impending winter storm for several southern Minnesota counties, including Hennepin. A winter storm warning will go into effect 7 p.m. Tuesday and end 1 p.m. Thursday.

A “wintry mix” of rain and sleet will move toward the Twin Cities this afternoon, according to the alert, before spreading east later Tuesday night.

“Anytime you get a winter storm in April … it gets to be pretty unique. They don’t happen every year,” said Jacob Beitlich, a National Weather Service meteorologist. “This is a significant storm.”

A powerful storm system coming off the Pacific coast, combined with cold air from the north, will produce the snowfall, he said, adding that snowfall will occur mostly between late Wednesday and mid-Thursday.

“This is a long duration event,” Beitlich said.

A covering of ice is expected to form beginning late Tuesday due to sleet, according to the alert.

Although 15 to 18 inches of snow are expected near the western border of Minnesota, Beitlich said the south metro should anticipate three to seven inches in total. 

Travel will be “very hazardous or impossible” during the storm, the alert warns, adding that potentially powerful winds are possible.

Though travel will likely be difficult Wednesday morning, Beitlich said the worst snowfall — and the worst commute — will come Thursday morning.

“It’ll slow things down,” he said.