Winter Storm in Monona, Iowa

The office received snowfall reports of 4.5 to 6.2 inches from the public and CO-OP Observers. The heaviest snowfall was estimated around the eastern edge of the county.

From Friday, November 28th into Saturday, November 29th, an amplifying mid-level trough progressed into the central Contiguous United States CONUS. In response, a surface low developed over central Colorado and tracked east along the Kansas/Oklahoma border Friday night before lifting into northern Missouri on Saturday.

Ahead of the system, warm air advection combined with a weak mid-level disturbance moving across South Dakota produced an initial round of light mixed precipitation across eastern Nebraska and southwest Iowa Friday afternoon and evening. Precipitation types included snow, sleet, and freezing drizzle. Continued warm air advection late Friday supported an expanding precipitation shield into the region.

The transition zone between rain, freezing rain/drizzle, and snow proved particularly challenging, becoming quasi-stationary from Seward, NE through Wahoo and Omaha, NE, to Red Oak, IA. This resulted in an initial period of freezing rain and freezing drizzle, followed by a transition to snow early Saturday. North of this transition zone, a persistent band of heavy snow developed and wrapped from western Iowa into extreme northeast Nebraska through Saturday morning. Snowfall totals were highest across northwestern Iowa and decreased southward and westward. Amounts generally ranged from 2 to 4 inches across east-central Nebraska, increasing to around 6 inches across eastern Nebraska, 6 to 7 inches in western Iowa, and locally exceeding 8 inches farther east into central Iowa.

Winds strengthened through the day Saturday as the surface pressure gradient tightened on the backside of the departing system, with peak gusts reaching up to 47 mph during the afternoon. The strongest snowfall rates occurred prior to the onset of the strongest winds, limiting the duration and severity of blowing and drifting snow. As a result, visibilities generally remained in the 3 to 5 statute mile range, with only brief reductions to around 1 statute mile.