A winter storm developed over the western United States on December 18th, and then moved into the central Plains on the 19th producing heavy snow, localized areas of sleet and freezing rain, and in some areas blizzard conditions. Light rain developed during the late morning and early afternoon on December 19th as moisture spread north into the area from the south. As cooler air worked into the storm system from the north, the rain mixed with and eventually changed over to snow. The change over from rain to snow initially occurred over central Nebraska, spreading into northeast and east central Nebraska, and eventually west central Iowa by mid to late afternoon. Snowfall coverage and intensity increased into the evening hours as the upper level storm system moved through Kansas. Areas of thunder snow were reported in parts of east central Nebraska and southwest Iowa. The snow mixed with sleet and freezing rain over parts of southwest Iowa during the event before finally changing over to all snow just before midnight. The change-over from rain to snow also occurred just before midnight over parts of far southeast Nebraska. As the area of surface low pressure deepened and moved through Missouri toward eastern Iowa, northwest winds increased across eastern Nebraska and western Iowa. Wind speeds of 40 to 50 mph were common from late evening on the 19th into the morning hours of the 20th. The combination of falling temperatures and increasing winds led to significant blowing and drifting of snow and areas of blizzard conditions, especially in open areas. Winds also combined with the initially heavy wet nature of the snow to create power outages for over 45,000 customers across the area. The heaviest snow fell in a band from Butler and Seward County in Nebraska, through the Omaha and Lincoln metro areas, and into west central Iowa. In this band 8 to 10 inches of snow were common with isolated amounts up to 10 inches reported in Saunders and Sarpy County in Nebraska. To the north and the south of this band snowfall amounts were lighter with 3 to 6 inches common. There were also reports of over a quarter inch of sleet and freezing rain in southwest Iowa around Page County, before the precipitation switched over to all snow. The storm finally came to an end by mid day on the 20th as the system pushed off to the east and the winds diminished.

Blizzard in MONONA, IOWA
From 19-DEC-12 21:00:00 to 20-DEC-12 11:00:00 (CST-6)
Reported by: AWOS

Surrounding AWOS stations indicated that gusts up to 40 mph were common across the county leading to reduced visibilities of a quarter mile or less, especially in open areas.

Blizzard in HARRISON, IOWA
From 19-DEC-12 23:00:00 to 20-DEC-12 07:00:00 (CST-6)
Reported by: AWOS

Surrounding AWOS stations indicated that gusts up to 40 mph were common across the county leading to reduced visibilities of a quarter mile or less, especially in open areas.

Blizzard in SHELBY, IOWA
From 19-DEC-12 23:00:00 to 20-DEC-12 11:00:00 (CST-6)
Reported by: AWOS

Surrounding AWOS stations indicated that gusts up to 40 mph were common across the county leading to reduced visibilities of a quarter mile or less, especially in open areas.

Blizzard in POTTAWATTAMIE, IOWA
From 19-DEC-12 23:30:00 to 20-DEC-12 12:00:00 (CST-6)
Reported by: AWOS

Surrounding AWOS stations indicated that gusts up to 40 mph were common across the county leading to reduced visibilities of a quarter mile or less, especially in open areas.

Blizzard in MILLS, IOWA
From 20-DEC-12 02:00:00 to 20-DEC-12 10:00:00 (CST-6)
Reported by: AWOS

Surrounding AWOS stations indicated that gusts up to 45 mph were common across the county leading to reduced visibilities of a quarter mile or less, especially in open areas.

Winter Storm in SHELBY, IOWA
From 19-DEC-12 16:00:00 to 20-DEC-12 12:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Heavy snow fell across most of Harrison County during the event. Snowfall amounts of 6 to 8 inches were common.

Winter Storm in POTTAWATTAMIE, IOWA
From 19-DEC-12 16:00:00 to 20-DEC-12 12:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Heavy snow fell across Pottawattamie County with most locations receiving between 5 and 7 inches.

Winter Storm in MONONA, IOWA
From 19-DEC-12 17:00:00 to 20-DEC-12 12:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snowfall across the county ranged from around 4 inches along the Missouri River to as much as 8 inches over the eastern half.

Winter Storm in FREMONT, IOWA
From 19-DEC-12 19:00:00 to 20-DEC-12 12:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snowfall across the country ranged from 2 to 3 inches at most locations. This snowfall combined with reports of sleet and light freezing rain to produce winter storm conditions and scattered power outages as winds increase to 30 to 40 mph.

Winter Storm in PAGE, IOWA
From 19-DEC-12 19:00:00 to 20-DEC-12 12:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snowfall across the country ranged from 2 to 3 inches at most locations. Up to 0.30 inches of sleet and freezing rain combined with the snow to produce winter storm conditions and scattered power outages as winds increased to 30 to 40 mph.