A mid-level disturbance worked northeast from Colorado early morning January 12 into Iowa by late day. Broad lift initially within the warm advection zone became increasingly concentrated, with deeper lift in the dendritic growth layer by afternoon across northwest Iowa.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FSD wrote it up.
A mid-level disturbance worked northeast from Colorado early morning January 12 into Iowa by late day. Broad lift initially within the warm advection zone became increasingly concentrated, with deeper lift in the dendritic growth layer by afternoon across northwest Iowa. Snowfall rates up to 1.5 to 2 inches per hour were noted across northwest Iowa and northeast Nebraska at the peak during the late afternoon.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sioux Falls, SD wrote its last area forecast discussion before the first event at Jan 12, 12:05 PM CST, 55 minutes earlier.
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</html>Hazardous Weather Outlook National Weather Service Sioux Falls SD 504 AM CST Sun Jan 12 2020 IAZ001>003-012>014-020>022-031-032-MNZ080-081-089-090-098-NEZ013-014- SDZ067-070-071-131115- Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee- Buena Vista-Woodbury-Ida-Murray-Cottonwood-Nobles-Jackson-Rock-Dixon- Dakota-Lincoln-Union- 504 AM CST Sun Jan 12 2020 This Hazardous Weather Outlook is for northwest Iowa, west central Iowa, southwest Minnesota, northeast Nebraska and southeast South Dakota. .DAY ONE...Today and tonight. Light snow will spread across the area from mid morning through early evening, with accumulations from 1 to 3 inches expected. .DAYS TWO THROUGH SEVEN...Monday through Saturday. While there will be multiple chances for snow Monday night through Wednesday, any accumulation will light. Late week could bring another round of precipitation to the region, and while snow is most likely, a wintry mix is possible in some areas. Details on this system are still uncertain, and will be refined as the week progresses. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MNZ071-072-097-SDZ038>040-050-052>066-068-069-131115- Lincoln-Lyon-Pipestone-Beadle-Kingsbury-Brookings-Gregory-Jerauld- Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook- Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton- 504 AM CST Sun Jan 12 2020 This Hazardous Weather Outlook is for southwest Minnesota, central South Dakota, east central South Dakota, south central South Dakota and southeast South Dakota. .DAY ONE...Today and tonight. There is a chance of light snow across far southeast South Dakota and southwest Minnesota today into early this evening. Any accumulation is expected to remain less than an inch, with higher amounts likely southeast of a line from Yankton, to Sioux Falls, to Marshall. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Areas of light snow will move across the area Tuesday night into Wednesday. Late week could bring another round of precipitation to the region, and while snow is most likely, a wintry mix is possible in some areas. Details on this system are still uncertain, and will be refined as the week progresses. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The national radar mosaic for the moment the first event began.
2 winter weather. Local standard time, as filed.
Moderate to briefly heavy snowfall during the afternoon accumulated to 5.0 inches at Ponca and 3.3 inches near Concord, resulting in hazardous road conditions.
Moderate to briefly heavy snowfall during the afternoon accumulated to 2.5 inches at Emerson and South Sioux City, resulting in hazardous road conditions.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nebraska in 2020Every state in 2020This day in weather historyWarnings in Nebraska, January 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 873950, 873951.