The first major winter storm of the 2012-2013 season brought widespread snowfall of generally 3 to 9 inches to the entire 24-county area, along with several hours of blizzard conditions to most counties. Officially, this was the first blizzard to blast South Central Nebraska in nearly three years...since the Christmas 2009 event. Wind and blowing snow created white-out conditions during most of the afternoon and evening of Wednesday the 19th, and travel became difficult if not impossible with reports of numerous accidents and road closures, including Interstate 80. Bands of moderate to heavy snow initially overspread most areas during the early to mid-afternoon hours, in some cases starting out as a brief period of rain or a rain/sleet/snow mix. Through the late afternoon and especially evening hours, full-fledged blizzard conditions blossomed as an expansive shield of snow combined with steadily increasing north winds featuring sustained speeds generally 25-35 MPH but frequently gusting 40-45 MPH. During this time a few lightning strikes (thundersnow) were also noted within the heaviest snow bands. Generally between 8 PM on the 19th and 2 AM on Thursday the 20th, the back edge of moderate to heavy snow gradually cleared South Central Nebraska from west to east, releasing its grip on the Highway 281 corridor around midnight. Even in the wake of falling snow, late night wind speeds were slow to decrease, keeping blowing snow going into the morning hours of the 20th.
The highest snowfall amounts of generally 5-9 focused within an east-west swath across the heart of the area, including much of the Interstate 80 and Highway 6 corridors. Per NWS cooperative observers, some of the highest totals included 10 near York, 9.1 at Central City and 8.1 at Hastings. To both the north and south of the primary snowfall zone, lesser amount of 3-4 were more common in the Ord, Greeley, Superior and Hebron areas. Liquid equivalent precipitation exceeded 1 inch in a few areas, including 1.04 at Grand Island. Interestingly, this was the highest calendar-day precipitation total of the entire year in Grand Island, which was quite unusual considering that the wettest days are almost always associated with spring or summer rainfall events. On the synoptic scale, this event was driven by a powerful, expansive mid-upper level trough translating eastward through the Central Plains, and featuring a closed 700 millibar low tracking across the northern half of Kansas. The most intense late afternoon and evening snow bands were associated with stout frontogenesis/deformation on the northwest side of the mid level circulation. At the surface, strong north winds and blizzard conditions were promoted by a tight pressure gradient on the north side of roughly 996 millibar low that tracked along the Kansas/Oklahoma border during the afternoon and evening.