April 2019 Summary: Cool and Wet

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 20^th 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 14^th.

Generally above average precipitation was recorded this month, and much above average snowfall. Watertown had its 10^th wettest April on record. Sisseton, Wheaton and Watertown had their 2^nd snowiest April on record, 5^th in Pierre, 6^th in Kennebec, 9^th in Mobridge and 10^th in Aberdeen. This was due exclusively to a winter storm of historic proportions, which affected the area from the 10^th through the 12^th. 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 30^th, 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°/ 20^th	83°/ 20^th	82°/ 20^th	80°/ 20^th
Coldest Temperature / Date	17°/ 14^th	14°/ 14^th	23°/ 14^th	14°/ 14^th
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”/ 11^th	0.83”/ 11^th	0.79”/ 11^th	1.26”/11^th
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” / 11^th	11.3” / 11^th	8.0” / 11^th	13.0” / 11^th

Temperature Data	Pierre	Kennebec	Mobridge	Timber Lake
Warmest Temperature / Date	90°/ 20^th	90°/ 20^th	88°/ 20^th	83°/ 20^th
Coldest Temperature / Date	23°/ 13^th	20°/ 13^th	18°/ 13^th	19°/ 13^th
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”/ 11^th	0.97”/ 10^th	0.79”/ 10^th	0.51”/ 10^th
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”/ 11^th	13.5” / 11^th	6.6” / 11^th	5.9” / 10^th

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