National Weather Service United States Department of Commerce

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 >

Temperatures finished near to slightly below normal on the whole across the area this April. The first 5 days featured record-territory warmth with highs in the 70s and 80s. In fact, Pierre and Mobridge set daily record highs on the 2nd, 3rd, and/or 4th. However, much of the remainder of the month would feature near normal to below normal temperatures. Some of the coldest air was observed on the 19-25th, when Pierre and Mobridge set at least one record low temperature each.  

Brown/Spink Counties and areas to the east recorded above average amounts of precipitation (by as much as around three quarters of an inch at Aberdeen and Wheaton), while the rest of the area was below average (by as much as around an inch at Mobridge and Timber Lake). For those with a surplus, much of the rain fell over a 3-day period from April 6-8th when a large, slow moving low pressure system tracked through. Daily records were set on the 7th at Aberdeen, Watertown and Sisseton when over an inch fell. The bullseye of this system was across Day, Roberts, Big Stone, Clark, Codington and Grant Counties where there was a storm total of 3 to 4 plus inches of rain. This led to river rises to near action flood stage in a few cases. As far as snowfall goes, the whole area recorded below average amounts. There were just a few days where at least a trace of snow fell (a few of which led to icy roads), but the most notable in terms of accumulations took place on the 20th from McPherson southeast to Deuel County during the afternoon and evening – up to 2 to 4” fell (fairly localized). Drought conditions worsened over the course of the month across north central SD, but improved or disappeared across portions of northeastern SD and west central MN.

Finally, below are the snowfall totals as of May 1st for the 2020-2021 cold season vs normal (based on the 1981-2010 climate normals – an update to these normal will take place in a couple days on May 4th).

Aberdeen: 31.7” vs 38.1” (-6.4”)

Watertown: 32.6” vs 35.9” (-3.3”)

Sisseton: 23.7” vs 44.5” (-20.8”)

Pierre: 24.2” vs 31.9” (-7.7”)

Mobridge: 17.2” vs 31.1” (-13.9”)

 

                                          April 2021

       

Temperature Data

Aberdeen

Sisseton

Wheaton

Watertown

Warmest Temperature / Date

80 / 4th  

79 / 5th   

76 / 5th   

82 / 5th   

Coldest Temperature / Date

12 / 1st  

15 / 1st  

16 / 1st  

15 / 1st  

Average High / Departure from Normal

58.7 / +1.7

56.4 / +0.1

53.1 / -2.1

54.8 / -0.8

Average Low / Departure from Normal

30.6 / -1.2

33.0 / +0.4

32.7 / +0.7

31.2 / -0.9

Monthly Average / Departure from Normal

44.7 / +0.3

44.7 / +0.2

42.9 / -0.7

43.0 / -0.8

Precipitation Data

 

 

 

 

Monthly Precipitation / Departure from Normal

2.59 / +0.74

2.66 / +0.38

2.94 / +0.70

2.44 / +0.42

Most Precipitation in 24 hours / Date

1.41 / 7th

1.56 / 7th

1.24 / 7th   

1.01 / 7th

Monthly Snowfall / Departure from Normal

1.7 / -1.4

T / -3.8

T / -4.4

0.9 / -2.4

Most Snow in 24 hours / Date

1.6 / 20th

T / 5 days  

T / 4 days

0.6 / 20th  

         

Temperature Data

Pierre

Kennebec

Mobridge

Timber Lake

Warmest Temperature / Date

84 / 4th  

86 / 4th

84 / 4th

80 / 4th, 5th  

Coldest Temperature / Date

18 / 20th

14 / 20th

17/20,21,24th  

16 / 21st

Average High / Departure from Normal

59.2 / -0.5

61.9 / -0.3

60.0 / +2.0

58.8 / +0.0

Average Low / Departure from Normal

30.9 / -3.3

30.7 / -3.3

29.5 / -3.0

29.7 / -3.0

Monthly Average / Departure from Normal

45.1 / -1.9

46.5 / -1.6

44.7 / -0.6

44.5 / -1.3

Precipitation Data

 

 

 

 

Monthly Precipitation / Departure from Normal

1.28 / -0.53

1.90 / -0.26

0.50 / -1.07

0.74 / -0.96

Most Precipitation in 24 hours / Date

0.81 / 6th  

1.14 / 7th

0.18 / 26th

0.34 / 26th    

Monthly Snowfall / Departure from Normal

T / -4.1

T / -3.9

T / -3.2

T / -5.3

Most Snow in 24 hours / Date

T / 5 days  

T / 20th, 21st  

T / 5 days

T / 12,13,20th   

 

 

 

Average temperature departure from normal this April on the whole, courtesy of the Midwestern Regional Climate Center

 

Daily high temperatures (value) and departures from normal (box shading) at Aberdeen, Watertown and Pierre. 

 

Total precipitation this April (left) and departures from normal (right), courtesy of the Midwestern Regional Climate Center

 

Total observed rainfall from April 6-8th.

 

Total snowfall this April (left) and departures from normal (right), courtesy of the Midwestern Regional Climate Center

 

US Drought Monitor comparison between the beginning (left) and end (right) of the month in South Dakota and Minnesota. 

 

Total snowfall during the 2020-2021 cold season, as of May 1st, 2021, courtesy of the Midwestern Regional Climate Center