The shortwave expected to impact our area late tonight and into tomorrow has finally arrived and will continue to move eastward through the Upper Mississippi Valley region over the next several hours. Moderate-to-heavy snow has developed ahead of this wave, as indicated by the radar mosaic taken in the image below. Road conditions have deteriorated across most points north of Highway 30, with roads completely covered in northwest and east central Iowa, including the Waterloo, Cedar Rapids, and Dubuque metros. To the west, roads remain partially covered.
Continued lift and forcing ahead of the front alongside a strengthening low-level jet will aid in snowfall rates up to a inch per hour in some areas, as detailed in Storm Prediction Center Mesoscale Discussion 61:
Heavy snow will continue to be prevalent through the early morning hours. Light snow will linger across eastern Iowa through mid-morning. Many schools and businesses have already delayed two hours as a result. A Winter Storm Warning remains in effect in central and east central Iowa through tomorrow, with a Winter Weather Advisory extending outside of this. Six-to-eight inches is expected from Prairie Du Chien to Humboldt to Fort Dodge to Cedar Rapids to Clinton. Some areas here may locally get as much as ten inches. Outside of this, four-to-six inches can be anticipated for most of the advisory area, with 2-4″ in the far northwest and southeast. A sharp cut-off will exist on the southern extent of the snowfall; amounts may have to be adjusted tonight accordingly.
Winds after midnight will pick up into the 10-15 MPH range with gusts to 25 MPH. This may cause some blowing and drifting snow tomorrow morning. Please make sure to give plenty of time to travel as you head to work tomorrow – our main source of concern is along Interstate 380 and Interstate 35 north of Ames to the Mason City area.
Stay tuned to the Iowa Weather Network for the latest updates.