A major winter storm is knocking on Iowa’s door. Twenty counties in central and western Iowa are under a Winter Storm Warning late tonight through tomorrow night. The watch area includes the cities of Council Bluffs, Denison, Atlantic, Creston, Ames and Des Moines.

National Weather Service meteorologist Frank Boksa says the storm will start with rain and change over to snow after midnight.

“We’re not looking for any big snowfall totals during the overnight hours – perhaps half-an-inch in the Des Moines metro.

Certainly, areas out west will change over first and they will see a little bit more snow by daybreak. We’re looking at two or three inches in western Iowa,” Boksa said. But, the heaviest snow is expected through the morning and early afternoon. Boksa said it’s difficult to forecast final snowfall totals because the snow will be so wet and heavy.

“Wet, heavy snow compacts more…this is a very difficult storm to try and pinpoint where the heaviest snow is going to be,” Boksa said. Some blowing and drifting of snow is possible tomorrow as northeast winds are expected between 15 and 30 miles an hour.

High temperatures across the state through the weekend will mostly be in the 30s.