Frontogenetic forcing in advance of an arctic cold push produced widespread snowfall across south central, southeast and east central South Dakota. Heaviest snowfall amounts were just north of Interstate 90.
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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.
Frontogenetic forcing in advance of an arctic cold push produced widespread snowfall across south central, southeast and east central South Dakota. Heaviest snowfall amounts were just north of Interstate 90.
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 Dec 21, 5:32 AM CST, 28 minutes earlier.
Area Forecast Discussion National Weather Service Sioux Falls SD 532 AM CST Thu Dec 21 2017 .SHORT TERM...(Today and Tonight) Issued at 236 AM CST Thu Dec 21 2017 Models trending a little upward in QPF amounts across the area, as well as trending just slightly northward with the band of precipitation. The GFS is the furthest north, placing the band of light precipitation closer to the highway 14 corridor, but the general consensus places the band along the axis of a line from near Gregory SD to Dell Rapids to Windom where 1 to 3 inches of snow will be possible. Locally higher amounts may be possible in south central SD where some enhanced forcing and lift arrives this morning. Amounts rapidly trail off heading towards Huron, as well as heading into northwest Iowa. Most areas in the forecast area will see 2 inches or less. Initial precipitation will struggle to reach the surface with a dry mid level layer putting a damper on things. With the stronger cold air advection arriving mid morning, light snow will become likely across the forecast area with the band setting up in the aforementioned axis and gradually shifting east southeast through the region into the afternoon. With the dendritic layer at times lacking within the cloud deck, some spotty light freezing drizzle or freezing rain could be possible at times, mainly in portions of northwest Iowa. Areas south of I-90 in SD will likewise see some spotty drizzle at times, but should quickly switch over to snowfall with cold air advection arriving sooner. As cold air advection and light snowfall works into northwest Iowa this afternoon, this forcing and the light snowfall becomes more widespread here, the rapidly weakens, resulting in minimal accumulations here. Northerly winds will gust to 20 to 30 mph at times today, which will result in visibility reductions at times while snow is falling. But with most locations in the forecast area seeing 2 inches or less of snowfall, will not issue any headlines at this time. Will need to keep an eye on the freezing drizzle potential and reevaluate headlines if it looks like a greater concern than current thinking. Snow will taper off this evening from northwest to southeast, ending in northwest Iowa late tonight. Temperatures will be fairly steady or even fall a bit through the daytime while lows tonight fall into the single digits to mid teens. .LONG TERM...(Friday through Wednesday) Issued at 236 AM CST Thu Dec 21 2017 West northwest upper level flow on Friday will lead to seasonal temperatures in the 20s and lower 30s as low level winds turn southwest to west. Partly cloudy skies and predominately dry conditions are expected. Another cold front arrives Friday evening, bringing another shot of colder air from Canada. The frontal passage will be dry, but breezy northerly winds and mostly cloudy skies return. Saturday will be cooler but still remaining in the upper teens and 20s for highs and single digits for lows. A reinforcing shot of cold air arrives for Sunday into Sunday night, leading lows on Christmas morning near zero and wind chills dropping into the single digits and teens below zero. The cold airmass looks like it will stick around into the first half of next week, with lows near zero and highs in the teens. Precipitation chances are uncertain, but with several waves tracking through the area during the arctic outbreak, light snow chances remain in the forecast. && .AVIATION...(For the 12Z TAFS through 12Z Friday morning) Issued at 532 AM CST Thu Dec 21 2017 Band of snow will bring MVFR to IFR conditions to the region through this evening, with embedded LIFR visibility possible at times. KHON expected to see least impact from the snow, while KFSD/KSUX see several hours of reduced visibility and low ceilings. May see a period of FZDZ at KSUX this morning, but confidence in development/timing is low given some lingering dry air near the surface, so opted to leave it out of the TAF for now. Will monitor closely, though, and amend if needed. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && SHORT TERM...08 LONG TERM...08 AVIATION...JH
Hazardous Weather Outlook National Weather Service Sioux Falls SD 343 AM CST Thu Dec 21 2017 IAZ001>003-MNZ071-072-080-081-089-090-097-098-SDZ040-050-052>070- 220945- Lyon IA-Osceola-Dickinson-Lincoln MN-Lyon MN-Murray-Cottonwood- Nobles-Jackson-Pipestone-Rock-Brookings-Gregory-Jerauld-Sanborn- Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-Minnehaha- Charles Mix-Douglas-Hutchinson-Turner-Lincoln SD-Bon Homme- Yankton-Clay SD- 343 AM CST Thu Dec 21 2017 This Hazardous Weather Outlook is for portions of northwest Iowa, southwest Minnesota, central South Dakota, east central South Dakota, south central South Dakota, and southeast South Dakota. .DAY ONE...Today and Tonight Light snow will become likely this morning and continue into this evening. Freezing drizzle may briefly fall this morning along and south of I-90 but will quickly change to light snow. Amounts are expected to be 1 to 2 inches with locally higher amounts in south central South Dakota. Gusty winds will accompany the snowfall, causing brief reduced visibility at times. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Much cooler conditions are expected this weekend into early next week. Wind chill readings may fall to ten to 20 degrees below zero by Christmas morning. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. IAZ012>014-020>022-031-032-NEZ013-014-SDZ071-220945- Sioux-O'Brien-Clay IA-Plymouth-Cherokee-Buena Vista-Woodbury-Ida- Dixon-Dakota-Union- 343 AM CST Thu Dec 21 2017 This Hazardous Weather Outlook is for portions of northwest Iowa, west central Iowa, northeast Nebraska, and southeast South Dakota. .DAY ONE...Today and Tonight Patchy freezing drizzle will be possible this morning, before changing over to light snowfall this afternoon. Any ice accumulation is expected to be minimal, though there could be isolated slippery spots on sidewalks and roadways. Snowfall amounts will generally be around a half inch or less. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Much cooler conditions are expected this weekend into early next week. Wind chill readings may fall to ten degrees below zero by Christmas morning. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. SDZ038-039-220945- Beadle-Kingsbury- 343 AM CST Thu Dec 21 2017 This Hazardous Weather Outlook is for portions of east central South Dakota. .DAY ONE...Today and Tonight Light snow is expected through this afternoon. Snowfall amounts will generally be around a half inch or less. Gusty winds will accompany the snowfall, causing reduced visibility at times. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Much cooler conditions are expected this weekend into early next week. Wind chill readings may fall to ten to 20 degrees below zero by Christmas morning. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
6 winter weather. Local standard time, as filed.
Snowfall during the morning and early afternoon accumulated to 3 to 5 inches, including 4.0 inches at Pipestone and 4.5 inches at Jasper, contributing to hazardous road conditions.
Snowfall during the morning and early afternoon accumulated to 3 to 5 inches, including 3.5 inches at Lake Wilson and 4.5 inches at Slayton, contributing to hazardous road conditions.
Snowfall during the morning and early afternoon accumulated to 2 to 4 inches, including 2.8 inches at Windom, contributing to hazardous road conditions.
Snowfall during the morning and early afternoon accumulated to 2 to 4 inches, including 3.3 inches at Luverne, contributing to hazardous road conditions.
Snowfall during the morning and early afternoon accumulated to 2 to 4 inches, including 2.0 inches at Worthington, contributing to hazardous road conditions.
Snowfall during the morning and early afternoon accumulated to 2 to 3 inches, including 2.2 inches 2 miles NE of Lakefield, contributing to hazardous road conditions.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2017Every state in 2017This day in weather historyWarnings in Minnesota, December 2017
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 2026-09-24. Each event’s entry at NCEI: 731417, 731418, 731419, 731420, 731421, 731422.