New Year's Eve 2012, a Monday, featured a widespread 4 to 7 inch snowfall across the six-county area, with some locally higher amounts. Although the vast majority of accumulating snow fell the daylight hours generally between 7 AM and 5 PM, the first flakes started flying during the pre-dawn hours mainly south of Highway 24, and very light snow or flurries lingered well past sunset. The most concentrated area of 6+ inch snowfall targeted Osborne, Mitchell and Jewell counties, where some of the highest amounts according to NWS cooperative observers and CoCoRaHS observers included 8.5 near Covert, 7 at Beloit and Hunter and 6.6 at Jewell. Slightly lower totals were reported across most of Phillips, Rooks and Smith Counties, including at Phillipsburg (5), Smith Center (4.7) and near Plainville (5.2). Although visibilities were reduced to less than one-half mile at times, sustained north-northeast winds generally averaged no more than 15-20 MPH, keeping significant blowing and drifting snow in check.
On the large scale aloft, the primary instigator for this event was an expansive, positively-tilted longwave trough migrating toward the Central Plains from the western United States. On a more localized scale, North Central Kansas snowfall focused underneath a pronounced band of mid level frontogenesis evident at 700 millibars, and likely tied to the left exit region of a 150+ knot upper jet streak stretched from eastern New Mexico into southern Kansas.