Snow is expected to overspread much of northern Iowa west to east during the day Tuesday as strong low pressure approaches the Missouri River Valley from the Plains. There could be a mix of rain along the highway 20 corridor into Tuesday night, but all of northern Iowa should see snow by Wednesday morning, with moderate to heavy accumulations expected. Northwest winds will also increase by this time, leading to blowing and drifting snow.
A winter storm warning has been issued from noon Tuesday, to 6pm CST Wednesday. Precipitation mainly in the form of snow will spread west to east across northern Iowa Tuesday. It may mix with some rain toward highway 20 initially into Tuesday night, but all snow is anticipated over northern Iowa and warning wide Wednesday, until diminishing later in the day. Blowing and drifting snow is also anticipated Wednesday as the wind increases.
Snowfall accumulations of 5 to 9 inches are possible in the winter storm warning. The snow may be wet and heavy initially Tuesday. East to southeast wind gusts to 30-mph Tuesday afternoon will then gust out of the northwest during the day Wednesday, from 30 to 35-mph. Substantial visibility restrictions due to blowing and drifting snow are likely, especially Wednesday after most of the snow accumulations.