On the morning of the 18th, upper air analysis showed longwave troughing over the central and eastern CONUS. Embedded in this pattern, a compact shortwave trough was analyzed over northeast Montana and southern Saskatchewan. At the surface, a low pressure system was deepening in the Wyoming-Colorado-Nebraska tri-state area. North of this developing surface low, a cold front extended along the Montana-Wyoming state line and northeast across North Dakota. During the day on the 18th, the aforementioned shortwave trough dove southward across the Plains. The surface cold front followed suit, moving south-southeast across the northern and central Great Plains while the surface low tracked south-southeast through the High Plains.
Ahead of this cold front and shortwave trough, strong forcing for ascent allowed for a shield of moderate to heavy snow to develop across northern Nebraska and South Dakota by 8 am. This area of snow moved into eastern Nebraska and western Iowa by 11 am that morning with the surface cold front lagging just behind the bulk of the precipitation. Snow continued to fill in across the region through the early afternoon hours with visibilities under a mile at times and gusty winds up to 30 miles per hour. After 3 pm, the surface cold front accelerated and undercut the back side of the snow falling across the region. This produced snow squall conditions across the central third of the CWA. For locations impacted by the snow squall, conditions rapidly deteriorated with near zero visibilities and winds gusting up to 50 miles per hour. These conditions lasted anywhere from 20 to 45 minutes before snow came to an end behind the snow squall. Several crashes were reported as a result of the snow squall, most of which was in Platte County. The largest crash of the event happened in this county on Highway 91 just outside of Humphrey where around 25 cars were involved in a pileup. One injury was reported and dozens of people were taken to local shelters. The National Weather Service in Valley issued the first two snow squall warnings in office history. The second of these warnings included the Lincoln and Omaha metropolitan areas, drawing media attention that lasted for days after the event.
Significant travel impacts did not end behind the snow squall. Continued gusty winds up to 45 miles per hour brought significant blowing and drifting snow through the evening hours across much of east-central Nebraska and western Iowa. This resulted in widespread road closures as snow drifts made travel extremely hazardous if not impossible. Many roads remained closed through the overnight hours and into the day on the 19th.