A deep trough across the southwestern U.S. in the early morning of Saturday, December 28 pushed eastward through the day, allowing low pressure to organize near the Oklahoma and Texas Panhandles. The storm intensified as it moved into eastern Nebraska and western Iowa by 0600CST December 29. Strong warming aloft ahead of the system led to periods of light rain or light mixed precipitation, while heavy snow organized in the trowal over central and northeast South Dakota.
Impacts from the storm became significant as the storm closed off in the mid-levels and slowed movement, only reaching southern Minnesota by 0600CST December 30. Precipitation changed over to snow as colder air collapsed southward, and winds increased to a gusty 40 to 55 mph across southeast South Dakota and adjacent areas. Snowfall totals ranged from 10 to 18 inches from the James River Valley westward, to 1 to 3 inches across much of northeast Nebraska and northwest Iowa.  A record daily precipitation of 1.38 inches was measured in Sioux City on December 28.

Winter Weather in LYON, IOWA
From 28-DEC-19 03:00:00 to 30-DEC-19 08:00:00 (CST-6)
Reported by: COOP Observer

A brief period of light freezing rain produced a glaze of icing early on Saturday, December 28 before temperatures climbed above freezing. Light mixed precipitation returned and changed quickly to snow early on December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 1.5 inches at Rock Rapids. Wind gusts reached as high as 41 mph at Sioux Falls and 38 mph at Sheldon by early Monday, December 30, resulting in blowing and drifting snow.

Winter Weather in OSCEOLA, IOWA
From 28-DEC-19 03:00:00 to 30-DEC-19 12:00:00 (CST-6)
Reported by: COOP Observer

A brief period of light freezing rain produced a glaze of icing early on Saturday, December 28 before temperatures climbed above freezing. Light mixed precipitation returned and changed quickly to snow early on December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 2.6 inches at Sibley. Wind gusts reached as high as 43 mph 2 miles northeast of Sibley by early Monday, December 30, resulting in blowing and drifting snow.

Winter Weather in O'BRIEN, IOWA
From 28-DEC-19 03:00:00 to 30-DEC-19 06:00:00 (CST-6)
Reported by: COOP Observer

A brief period of light freezing rain produced a glaze of icing early on Saturday, December 28 before temperatures climbed above freezing. Light mixed precipitation returned and changed quickly to snow early on December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 2.1 inches at Sanborn and 1.3 inches at Primghar. Wind gusts reached as high as 38 mph at Sheldon by early Monday, December 30, resulting in blowing and drifting snow.

Winter Weather in SIOUX, IOWA
From 28-DEC-19 03:00:00 to 30-DEC-19 06:00:00 (CST-6)
Reported by: COOP Observer

A brief period of light freezing rain produced a glaze of icing early on Saturday, December 28 before temperatures climbed above freezing. Light mixed precipitation returned and changed quickly to snow early on December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 1.2 inches at Hawarden, Orange City and Sioux Center. Wind gusts reached as high as 37 mph at Alton by early Monday, December 30, resulting in blowing and drifting snow.

Winter Weather in PLYMOUTH, IOWA
From 28-DEC-19 03:00:00 to 30-DEC-19 06:00:00 (CST-6)
Reported by: COOP Observer

A brief period of light freezing rain produced a glaze of icing early on Saturday, December 28 before temperatures climbed above freezing. Light mixed precipitation returned and changed quickly to snow early on December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 1.9 inches at Le Mars. Wind gusts reached as high as 38 mph at Le Mars by early Monday, December 30, resulting in blowing and drifting snow.

Winter Weather in WOODBURY, IOWA
From 29-DEC-19 09:00:00 to 30-DEC-19 08:00:00 (CST-6)
Reported by: COOP Observer

Light mixed precipitation returned and changed quickly to snow around midday on December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 0.8 inches in Sioux City. Wind gusts reached as high as 52 mph at Sioux City by early Monday, December 30, resulting in blowing and drifting snow.

Winter Weather in DICKINSON, IOWA
From 28-DEC-19 03:00:00 to 30-DEC-19 15:00:00 (CST-6)
Reported by: COOP Observer

A brief period of light freezing rain produced a glaze of icing early on Saturday, December 28 before temperatures climbed above freezing. Light mixed precipitation returned and changed quickly to snow late on December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 1.8 inches at Lake Park, 1.7 inches 4 miles northwest of Milford, and 1.4 inches at Spirit Lake. Wind gusts reached as high as 40 mph at Spencer and 35 mph at Jackson by early Monday, December 30, resulting in blowing and drifting snow.

Winter Weather in CLAY, IOWA
From 28-DEC-19 05:00:00 to 30-DEC-19 12:00:00 (CST-6)
Reported by: COOP Observer

A brief period of light freezing rain produced a glaze of icing early on Saturday, December 28 before temperatures climbed above freezing. Light mixed precipitation returned and changed quickly to snow during the afternoon of December 29, then continued into December 30 producing hazardous travel. Snowfall totaled 2.6 inches 3 miles west northwest of Everly and 1.9 inches at Spencer. Wind gusts reached as high as 40 mph at Spencer by early Monday, December 30, resulting in blowing and drifting snow.  Around 1100CST on December 30, a northbound semi-truck lost control on snow-covered U.S. Highway 71 approximately 2 miles south of Spencer.  A fatality (indirect) occurred to the driver of a southbound minivan when the vehicle struck the semi-trailer extending across the highway.