Summer 2016 in Review

Climate Information

Severe Weather

The meteorological summer (June through August 2016) across central and northeast South Dakota and west central Minnesota observed temperatures generally from 1 to 3 degrees above average… a continuation from the strong El Nino-induced above average winter and spring. While all three months were warm relative to what’s typical, June was the warmest with many locations between 4 and 6 degrees above average. Aberdeen reached 100 degrees on June 9^th, a very early date to first reach the century mark. July however recorded the hottest temperatures with Pierre topping out at 109 F. High humidity often accompanied this heat, as is typical during the summer months, leading to several days of heat index values above 100 F.

Summer began with very dry conditions to go along with the heat in June, with some locations across eastern South Dakota and west central Minnesota up to 3 inches below normal. However, a pattern change took place during July and lasted into August as precipitation fell in abundance, particularly across eastern South Dakota and west central Minnesota. Ortonville, MN received 0.97” of rain on July 12^th and then an amazing 5.55” additional on the 13^th, which led to flooding in the area. This area continued to be the bullseye of more heavy rain in the month of August. 5.29” of rain fell in Watertown from August 10^th-11^th and much of the area fully recovered from drought after a dry start to the year. Meanwhile, parts of central South Dakota missed out on widespread heavy rains this summer which has allowed the drought to linger into the beginning of September (driest conditions continued across western South Dakota).

*Summer 2016*
Temperature Data (Jun-Aug)	Aberdeen	Sisseton	Watertown	Wheaton
Highest Temperature	100 / Jun 9^th	97 / Jun 12^th	96 / Jun 12^th, 19^th	94 / Jun 13^th, 20^th
Lowest Temperature	40 / Jun 2^nd	41 / Jul 1^st	42 / Jul 1^st	45 / Jul 1^st
Average Temperature	71.0	70.0	71.4	70.0
Temperature Departure	+2.4	+1.2	+2.9	+0.8
Highest Wind Gust	73 mph / Jul 16^th	83 mph / Jul 10^th	46 mph / Jun 3^rd	N / A
Precipitation Data (Jun-Aug)
Precipitation Total	7.12	10.40	10.99	11.31
Precipitation Departure	-2.03	+0.64	+1.61	+1.31

Temperature Data (Jun-Aug)	Pierre	Mobridge	Kennebec	Timber Lake
Highest Temperature	109 / Jul 20^th	105 / Jul 20^th	105 / Jul 20^th	107 / Jul 20^th
Lowest Temperature	45 / Jun 2^nd, 7^th Aug 26^th	47 / Jul 1^st	41 / Jun 7^th	46 / Jun 23^rd
Average Temperature	73.5	73.8	74.6	72.1
Temperature Departure	+1.2	+3.8	+1.6	+2.0
Highest Wind Gust	58 mph / Jul 30^th	68 mph / Jul 30^th	N / A	N / A
Precipitation Data (Jun-Aug)
Precipitation Total	8.28	6.59	8.13	6.48
Precipitation Departure	+0.30	-1.30	+0.36	-1.15

While not a very active tornado season, many supercells produced large hail and even more squall lines, bow echoes, and other severe wind-producing storms pummeled the area. June started out dry as not very many large storm systems crossed the area. However, a wound-up area of low pressure produced low-topped supercells on June 14th. While no severe straight-line wind or large hail was observed, 6 EF-0 tornadoes spun up from the Webster, SD area east northeast into the Wilmot, SD area. The area then became much more active in July. July 6th featured a bow echo across central South Dakota, July 9th two converging squall lines across northeastern South Dakota and west central Minnesota (leading to hundreds of trees downed in Browns Valley, MN), and a severe squall line and tornadic supercell on July 16th to list a few. August was another very active month, particularly for severe wind-producing storms. The two most active days were August 9th and 10th when a bow echo straddling the North Dakota/South Dakota state line was followed the next day by several supercells and squall lines. Many towns and rural areas suffered severe damage during the course of these events.

An overlay of all 243 Severe Thunderstorm Warnings, 15 Tornado Warnings, and 6 Flash Flood Warnings issued by our Aberdeen, SD National Weather Service Office from June 1st through August 31st:

An overlay of the 29 Severe Thunderstorm Warnings and 5 Tornado Warnings issued during the month of June:

An overlay of the 103 Severe Thunderstorm Warnings and 5 Tornado Warnings, and 2 Flash Flood Warnings issued during the month of July:

An overlay of the 111 Severe Thunderstorm Warnings and 5 Tornado Warnings, and 4 Flash Flood Warnings issued during the month of August: