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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 >

April 2019 featured generally slightly below average temperatures on a whole. Two main waves of above average temperatures were observed, one in early April and another in mid to late April. The 20th had high temperatures in the mid 80s to low 90s. Otherwise, conditions were on the chilly side with numerous daytime highs of 10-15 or more degrees below average. Sisseton set a daily record for a low temperature of 14 degrees on the 14th.

Generally above average precipitation was recorded this month, and much above average snowfall. Watertown had its 10th wettest April on record. Sisseton, Wheaton and Watertown had their 2nd snowiest April on record, 5th in Pierre, 6th in Kennebec, 9th in Mobridge and 10th in Aberdeen. This was due exclusively to a winter storm of historic proportions, which affected the area from the 10th through the 12th. Daily records for precipitation and snowfall, as well as much more information, can be found here: https://www.weather.gov/abr/April112019BlizzardSummary  

As a result of more moisture on top of already saturated soils and swollen streams and lakes, flooding continued to plague the area. As of April 30th, a couple river gauges on the James River remain at Major Flood Stage.

 

                                            APRIL 2019

       

Temperature Data

Aberdeen

Sisseton

Wheaton

Watertown

Warmest Temperature / Date

86°/ 20th  

83°/ 20th  

82°/ 20th     

80°/ 20th  

Coldest Temperature / Date

17°/ 14th      

14°/ 14th    

23°/ 14th   

14°/ 14th       

Average High / Departure from Normal

54.5°/ -2.5°

51.9°/ -4.4°

54.1°/ -1.1°

52.0°/ -3.6°

Average Low / Departure from Normal

33.3°/ +1.5°

34.4°/ +1.8°

37.4°/ +5.4°

32.6°/ +0.5°

Monthly Average / Departure from Normal

43.9°/ -0.5°

43.2°/ -1.3°

45.8°/ +2.2°

42.3°/ -1.5°

Precipitation Data

       

Monthly Precipitation / Departure from Normal

1.42”/ -0.43”

 2.95”/+0.67”

2.02”/ -0.22”

3.99”/+1.97”

Most Precipitation in 24 hours / Date

0.50”/ 11th    

0.83”/ 11th  

0.79”/ 11th  

1.26”/11th     

Monthly Snowfall / Departure from Normal

13.6” / +10.5”

18.6”/ +14.8”

12.5” / +8.1”

25.0”/ +21.7”

Most Snow in 24 hours / Date

6.4” / 11th  

11.3” / 11th

8.0” / 11th

13.0” / 11th     

         

Temperature Data

Pierre

Kennebec

Mobridge

Timber Lake

Warmest Temperature / Date

90°/ 20th     

90°/ 20th       

88°/ 20th      

83°/ 20th   

Coldest Temperature / Date

23°/ 13th    

20°/ 13th      

18°/ 13th   

19°/ 13th    

Average High / Departure from Normal

56.6°/ -3.1°

60.3°/ -1.9°

55.2°/ -2.8°

54.7°/ -4.1°

Average Low / Departure from Normal

33.9°/ -0.3°

33.8°/ -0.2°

33.6°/ +1.1°

33.4°/ +0.7°

Monthly Average / Departure from Normal

45.3°/ -1.7°

47.3°/ -0.8°

44.4°/ -0.9°

44.4°/ -1.4°

Precipitation Data

       

Monthly Precipitation / Departure from Normal

3.27”/ +1.46”

2.89”/ +0.73”

2.07”/+0.50”

2.45”/ +0.75”

Most Precipitation in 24 hours / Date

1.04”/ 11th       

0.97”/ 10th      

0.79”/ 10th  

0.51”/ 10th  

Monthly Snowfall / Departure from Normal

16.1” / +12.0”

18.7” /+14.8"

10.6”/ +7.4”

9.7”/ +4.4"

Most Snow in 24 hours / Date

10.2”/ 11th     

13.5” / 11th  

6.6” / 11th   

5.9” / 10th   

 

 

Temperature departures from normal, from the Midwestern Regional Climate Center

 

Precipitation totals (left) and departures from normal (right), from the Midwestern Regional Climate Center

Snowfall totals (left) and departures from normal (right), from the Midwestern Regional Climate Center

 

From the Midwestern Regional Climate Center, "Winter seasons have significant societal impacts across all sectors ranging from direct human health and mortality to commerce, transportation, and education. The question “How severe was this winter?” does not have a simple answer. At the very least, the severity of a winter is related to the intensity and persistence of cold weather, the amount of snow, and the amount and persistence of snow on the ground. The Accumulated Winter Season Index (AWSSI) was developed to objectively quantify and describe the relative severity of the winter season."

The AWSSI places this season at Pierre, Watertown and Aberdeen in the "Extreme" category. Visit https://mrcc.illinois.edu/research/awssi/indexAwssi.jsp and click on each location to see details. 

 

Finally, here are a couple graphics highlighting the incredible season this area had snow-wise