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Back-to-Back Pacific Storms to Impact the West Coast; Heavy Snow in the Central Appalachians

Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >

October finished above average temperature-wise across the area, by 2 to 6 degrees. The warmest periods were from the 2nd through the 9th and from the 16th through the 19th when high temperatures rose into the 70s and 80s. Overall on the year, Aberdeen has now recorded 116 days with a high temperature of at least 80 degrees in 2021, which ranks as the 3rd most on record (118 days in 1936 and 1900). Similarly, Timber Lake has had 106 days which ties for 4th most, Sisseton 103 days which ranks 6th, and Mobridge 106 days which ranks 9th. Cooler temperatures arrived for the second half of the month: the growing season ended, as hard freezes occurred, and albeit light, the first snow of the season took place at some locations on the 20th.  

A shift to a wetter pattern, particularly across northeastern South Dakota, continued into October when several systems impacted the area. Wheaton and Mobridge recorded their 8th wettest October on record, Timber Lake 7th, Sisseton and Aberdeen 6th, and Watertown 2nd with 7.63” of rainfall (8.10” in 1971). Daily record rainfall occurred on the 9th, 13th, 20th and 27th at Aberdeen, Watertown, Sisseton and/or Mobridge. Unfortunately, late-season severe weather including several tornadoes accompanied these systems on the 9th and 13th across northeastern South Dakota and west central Minnesota. Prior to 2021, there had been just 18 total October tornadoes confirmed in the state of South Dakota, and 29 in Minnesota. 10 additional tornadoes were confirmed in South Dakota and 14 in Minnesota this October alone. Find much more information here: https://www.weather.gov/abr/October2021SevereWeather. Drought conditions continued to improve in response, going from D3/Severe Drought across portions of north central SD and D2/Severe Drought across the majority of Central SD on September 28th, to just portions of D2/Severe Drought across Central SD by October 26th.  

 

                          October 2021

       

Temperature Data

Aberdeen

Sisseton

Wheaton

Watertown

Warmest Temperature / Date

88 / 4th

84 / 4, 5th

82 / 5th

81 / 4, 8th

Coldest Temperature / Date

25 / 29th

23 / 23rd

28 / 23rd

28 / 16, 31st

Average High / Departure from Normal

63.6 / +4.3

62.8 / +4.8

64.4 / +3.7

61.0 / +4.8

Average Low / Departure from Normal

39.9 / +6.6

41.7 / +6.2

42.1 / +5.4

40.2 / +5.0

Monthly Average / Departure from Normal

51.8 / +5.5

52.3 / +5.5

51.7 / +4.5

50.6 / +4.9

Precipitation Data

 

 

 

 

Monthly Precipitation / Departure from Normal

4.39 / +2.25

4.97 / +2.64

4.27 / +2.27

7.63 / +5.68

Most Precipitation in 24 hours / Date

1.18 / 9th

1.35 / 13th

1.35 / 10th

2.27 / 9-10th

Monthly Snowfall / Departure from Normal

T / -1.3

0.0 / -1.0

0.0 / -1.0

T / -1.4

Most Snow in 24 hours / Date

T / 20th

0

0

T / 24th

 

 

 

 

 

Temperature Data

Pierre

Kennebec

Mobridge

Timber Lake

Warmest Temperature / Date

86 / 4, 5th

83 / 4, 5th

87 / 5th

88 / 4, 5th

Coldest Temperature / Date

25 / 31st

25 / 15th

22 / 31st

19 / 21st

Average High / Departure from Normal

63.8 / +3.1

64.6 / +0.8

63.5 / +3.1

61.8 / +3.1

Average Low / Departure from Normal

40.7 / +4.5

39.6 / +4.0

41.4 / +4.9

39.6 / +5.0

Monthly Average / Departure from Normal

52.2 / +3.7

52.1 / +2.4

52.4 / +4.0

50.7 / +4.0

Precipitation Data

 

 

 

 

Monthly Precipitation / Departure from Normal

2.09 / +0.40

3.07 / +1.44

3.43 / +1.62

3.45 / +1.66

Most Precipitation in 24 hours / Date

0.70 / 9th

1.23 / 20th

1.52 / 12-13th

1.89 / 13th

Monthly Snowfall / Departure from Normal

0.0 / -1.3

0 / -1.6

T / -1.7

0.2 / -2.1

Most Snow in 24 hours / Date

0

0

T / 20th

0.2 / 20th

 

October 2021 temperature departure from normal, from the Midwestern Regional Climate Center

 

Daily high temperatures (values) and departures from normal (rectangle shading) at Aberdeen, Watertown and Pierre

 

October 2021 precipitation totals, from the Midwestern Regional Climate Center

 

October 2021 precipitation departure from normal, from the Midwestern Regional Climate Center

 

US Drought Monitor comparison between October 26th, left, and September 28th, right. 

 

Precipitation accumulation graph from January 1st through November 1st, at Aberdeen, Watertown, Sisseton, Pierre and Mobridge (from top to bottom, in that order). At Aberdeen and Mobridge, more rain has fallen from Aug 18th - Nov 1st than from Jan 1st - Aug 18th (10.18" vs 8.04" at Aberdeen and 8.67" vs 6.16" at Mobridge). Also, notice that rainfall deficits have turned to surpluses at Watertown and Sisseton.