A long duration winter weather event ensued after Christmas as a full-latitude trough moved through the Rockies on December 26, initiating cyclogenesis as the mid-level wave closed off and lifted northeast from TX into KS by early on December 27.  A leading pulse of warm advection ahead of the main system produced a swath of mixed precipitation on the 26th into early on the 27th across southeast SD and southwest MN.  This area weakened before the main wave lifted across the area on the 27th and sheared into northern Minnesota by early morning December 28.  A significant dry slot pushed across Iowa early on the 27th allowing for a brief change in precipitation to liquid or freezing precipitation. Heavier snowfall redeveloped within the TROWAL during the 27th and continued through the following night across southeast SD into southwest MN.
As the area of low pressure strengthened moving across Iowa during the afternoon of December 27, winds increased with gusts of 40 to 55 mph common into the early morning of December 28.

Winter Storm in BROOKINGS, SOUTH DAKOTA
From 26-DEC-18 15:00:00 to 28-DEC-18 07:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain between 1800-2300CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 30 to 40 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 10.0 inches 2 miles south of Astoria, 8.7 inches 5 miles west of Bruce, and 7.0 to 8.0 inches around Brookings with a peak wind gust of 41 mph. No travel was recommended during the height of the storm.

Winter Storm in MINNEHAHA, SOUTH DAKOTA
From 27-DEC-18 09:00:00 to 28-DEC-18 10:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing to light rain from 1300-0700CST.  Snow redeveloped during the morning of December 27, becoming moderate to heavy through the afternoon and early evening with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1800CST December 27 through 0600CST December 28.  Snowfall accumulated to 8.0 inches at Wall Lake and 4.0 to 6.5 inches around Sioux Falls, with a peak wind gust of 43 mph. No travel was recommended during the height of the storm.

Winter Storm in MINER, SOUTH DAKOTA
From 27-DEC-18 00:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain and rain from 1800-0000CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 6.5 inches at Howard with a peak wind gust of 48 mph at Madison. No travel was recommended during the height of the storm.

Winter Storm in JERAULD, SOUTH DAKOTA
From 26-DEC-18 09:00:00 to 28-DEC-18 03:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, decreasing during the afternoon before recharging during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as a half mile or less at times. Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0600CST December 28. Snowfall accumulated to 9.5 inches at Wessington Springs, with a peak wind gust of 51 mph. No travel was recommended during the height of the storm.

Winter Storm in MCCOOK, SOUTH DAKOTA
From 27-DEC-18 06:00:00 to 28-DEC-18 03:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain or rain from 1200-0000CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 8.0 inches 5 miles northeast of Salem and 6.0 inches at Montrose, with a peak wind gust of 43 mph at Sioux Falls and 48 mph at Madison. No travel was recommended during the height of the storm.

Winter Storm in HANSON, SOUTH DAKOTA
From 27-DEC-18 03:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain or rain from 1200-0000CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 11.4 inches at Mitchell with a peak wind gust of 55 mph. No travel was recommended during the height of the storm.

Winter Storm in LAKE, SOUTH DAKOTA
From 27-DEC-18 09:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain and rain from 1600-0000CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1500CST December 27 through 0600CST December 28.  Snowfall accumulated to 7.1 inches near Chester and 6.0 inches at Madison with a peak wind gust of 48 mph. No travel was recommended during the height of the storm.

Winter Storm in DOUGLAS, SOUTH DAKOTA
From 27-DEC-18 00:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow and light mixed precipitation developed in the early morning on December 26, changing to light rain around 1200CST. Snow redeveloped around 0000CST December 27, becoming moderate to heavy through the afternoon of December 27. Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0600CST December 28. Snowfall accumulated to 8.0 inches 2 miles south of Armour, with a peak wind gust of 48 mph near Geddes and 41 mph at Parkston, along with several hours of visibility of one half mile or less. No travel was recommended during the height of the storm.

Winter Storm in TURNER, SOUTH DAKOTA
From 27-DEC-18 07:00:00 to 28-DEC-18 12:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing to light rain from 1200-0200CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon and early evening of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 8.7 inches at Marion with a peak wind gust of 45 mph at Yankton and 43 mph at Sioux Falls. No travel was recommended during the height of the storm.

Winter Storm in GREGORY, SOUTH DAKOTA
From 26-DEC-18 09:00:00 to 28-DEC-18 05:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain from 1300-2100CST. Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility of a half mile or less at times. Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0200CST December 28. Snowfall accumulated to 10.0 inches 8 miles south southwest of Herrick, 7.8 inches 4 miles south southwest of Pickstown, and 7.0 inches at Gregory, with a peak wind gust of 49 mph near Fairfax and 51 mph at Winner. No travel was recommended during the height of the storm.

Winter Storm in MOODY, SOUTH DAKOTA
From 27-DEC-18 09:00:00 to 28-DEC-18 10:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing to light rain from 1400-0600CST.  Snow redeveloped during the morning of December 27, becoming moderate to heavy through the afternoon and early evening with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1800CST December 27 through 0600CST December 28.  Snowfall accumulated to 6.7 inches at Flandreau with a peak wind gust of 41 mph. No travel was recommended during the height of the storm.

Winter Storm in BEADLE, SOUTH DAKOTA
From 26-DEC-18 09:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Snow developed early in the morning on December 26, changing briefly to light freezing rain from 1600-1900CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 7.5 to 13.5 inches around Huron, with a peak wind gust of 51 mph. No travel was recommended during the height of the storm.

Winter Storm in AURORA, SOUTH DAKOTA
From 27-DEC-18 00:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow and light mixed precipitation developed early morning on December 26, changing to light rain around 1200CST. Snow redeveloped around 0000CST December 27, becoming moderate to heavy through the afternoon of December 27. Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0600CST December 28. Snowfall accumulated to 9.2 inches at White Lake, 9.1 inches at Stickney and 8.5 inches at Plankinton, with a peak wind gust of 47 mph at White Lake, along with several hours of visibility of one half mile or less. No travel was recommended during the height of the storm.

Winter Storm in KINGSBURY, SOUTH DAKOTA
From 26-DEC-18 15:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain and rain from 1800-2300CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 7.3 inches at Iroquois and 7.0 inches at De Smet with a peak wind gust of 46 mph. No travel was recommended during the height of the storm.

Winter Storm in BRULE, SOUTH DAKOTA
From 26-DEC-18 09:00:00 to 28-DEC-18 03:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain around 1400CST. Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility of a half mile or less at times. Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0400CST December 28. Snowfall accumulated to 6.7 inches at Chamberlain and 7.5 inches 5 miles south of Chamberlain, with a peak wind gust of 41 mph at Chamberlain. No travel was recommended during the height of the storm.

Winter Storm in BON HOMME, SOUTH DAKOTA
From 27-DEC-18 03:00:00 to 28-DEC-18 09:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain or rain from 1200-0000CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 7.3 inches at Tyndall with a peak wind gust of 41 mph at Parkston and 45 mph at Yankton. No travel was recommended during the height of the storm.

Winter Storm in SANBORN, SOUTH DAKOTA
From 27-DEC-18 00:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow and light mixed precipitation developed early in the morning on December 26, changing to light rain around 1200CST. Snow redeveloped around 0000CST December 27, becoming moderate to heavy through the afternoon of December 27 with several hours of visibility of one half mile or less. Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0600CST December 28. Snowfall accumulated to 9.0 inches near Forestburg, with a peak wind gust of 55 mph at Mitchell and 51 mph at Huron. No travel was recommended during the height of the storm.

Winter Storm in DAVISON, SOUTH DAKOTA
From 27-DEC-18 01:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow and light mixed precipitation developed early in the morning on December 26, changing to light rain around 1200CST. Snow redeveloped around 0000CST December 27, becoming moderate to heavy through the afternoon of December 27 with several hours of visibility of one half mile or less. Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0600CST December 28. Snowfall accumulated to 11.4 inches at Mitchell, with a peak wind gust of 55 mph. No travel was recommended during the height of the storm.

Winter Storm in CHARLES MIX, SOUTH DAKOTA
From 27-DEC-18 00:00:00 to 28-DEC-18 06:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing to light rain around 1200CST. Snow redeveloped around 0000CST December 27, becoming moderate to heavy through the afternoon of December 27. Northwest winds increased with gusts commonly from 40 to 50 mph from 1200CST December 27 through 0600CST December 28. Snowfall accumulated to 9.0 inches at Platte and near Academy, with a peak wind gust of 48 mph near Geddes along with several hours of visibility of one half mile or less. No travel was recommended during the height of the storm.

Winter Storm in YANKTON, SOUTH DAKOTA
From 27-DEC-18 07:00:00 to 28-DEC-18 12:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing to light rain from 1200-0200CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon and early evening of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 8.5 inches at Yankton with a peak wind gust of 45 mph. No travel was recommended during the height of the storm.

Winter Storm in HUTCHINSON, SOUTH DAKOTA
From 27-DEC-18 03:00:00 to 28-DEC-18 09:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow developed early in the morning on December 26, changing briefly to light freezing rain or rain from 1200-0000CST.  Snow redeveloped during the overnight hours, becoming moderate to heavy through the afternoon of December 27 with visibility as low as one half mile or less at times.  Northwest winds increased with gusts commonly from 35 to 45 mph from 1200CST December 27 through 0600CST December 28.  Snowfall accumulated to 6.5 inches at Menno and Parkston with a peak wind gust of 41 mph at Parkston. No travel was recommended during the height of the storm.