A widespread long-lived wind storm called a derecho, moved northeast out of Colorado and Wyoming and through western and central South Dakota during the evening of June 6th. Severe winds of 60 to 95 mph caused damage to structures along with causing tree damage.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS ABR wrote it up.
A widespread long-lived wind storm called a derecho, moved northeast out of Colorado and Wyoming and through western and central South Dakota during the evening of June 6th. Severe winds of 60 to 95 mph caused damage to structures along with causing tree damage.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Aberdeen, SD wrote its last area forecast discussion before the first event at Jun 6, 6:18 PM CST, 2 hours 24 minutes earlier.
Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 718 PM CDT Sat Jun 6 2020 .UPDATE... Issued at 702 PM CDT Sat Jun 6 2020 See below for an aviation forecast discussion for the 00Z TAFs. Mesoscale Discussion: Severe Thunderstorm Watch 264 in effect until 06Z covers the Missouri River valley (east and west-river) counties. Watching a large and dangerous squall-line type of line of storms working out of Wyoming and western Nebraska. Lots of severe thunderstorm wind reports coming out of this large convective system. Further east, within the warm air advection/moisture advection elevating off the warm front, have already seen one very large supercellular structure going up over southeast South Dakota including some additional weaker convection over southern/southeastern portions of this CWA. Continuing to watch the severe convection into the western CWA within the next few hours, and continuing to monitor the southern/southeastern forecast zones for any additional elevated potentially strong thunderstorms. && .SHORT TERM...(This Evening through Sunday Night) Issued at 319 PM CDT Sat Jun 6 2020 Currently looking at a low pressure system over eastern Montana/Wyoming, with a warm front extending from it along the South Dakota/Nebraska border. Main challenge in the short term is severe weather chances tonight and again later in the day Sunday. Scattered showers and thunderstorms have occurred in association with a warm front across a good portion of the area today, with just a couple reports of very small hail. This activity looks to push off to the east by this evening. The bigger concern comes later tonight as a 50 to 60 knot low level jet develops in conjunction with a line of storms expected to move in from the west. Lapse rates increase to around 6.5-8 degrees C/km as well, which should aid in creating the potential for strong winds gusts with the line of storms. The best timing for this line to move through based of current CAMS looks to be between 02Z and 09Z. Things then quiet down for a bit, with more sun expected on Sunday. The warm front slides north, allowing for very warm and moist air to move into the region. Temperatures rise into the 90s with dewpoints well into the 60s, which will allow for strong instability to develop before the cold front associated with the low reaches the area. By 18Z Sunday, CAPE values in excess of 3500 J/kg will develop over the eastern CWA, then will increase to almost 5000 J/kg by late afternoon. The one hindering factor for convective development will be a bit of a CAP. but CAMS all pretty much agree that the CAP will likely break and storms will develop. Gusty winds and hail will be the main threats, but as bulk shear increases to 55 to 70 knots late in the afternoon, cannot rule out a tornado or two. These storms look to come to an end around 06Z Monday. Low temperatures tonight will range from the lower 60s northwest to the lower 70s southeast, with highs in the 90s on Sunday. Lows Sunday night will range from the upper 50s northwest to the lower 70s east Sunday night. .LONG TERM...(Monday through Saturday) Issued at 319 PM CDT Sat Jun 6 2020 The period begins on Monday with a cold front slowly moving eastward across the CWA. Convection should develop along the front during the late afternoon hours over northern Nebraska and southeast SD. Fueled by a 40 knot LLJ, these storms should progress northeast over the eastern half of the CWA Monday night into Tuesday. Training thunderstorms will be possible with locally heavy rainfall the main threat Monday night. Rainfall amounts of 1 to 3 inches could be possible. Once the front pushes east the region, the CWA will see much cooler and dry conditions. High temperatures for the rest of the work week will only reach the upper 60s, to the mid 70s. Additional showers and thunderstorms will be possible on Tuesday due to the remnants of Cristobal. High pressure should slide over the region on Friday and Saturday with dry and less windy conditions expected. && .AVIATION...(For the 00Z TAFS through 00Z Sunday Evening) Issued at 702 PM CDT Sat Jun 6 2020 Terminals KABR,KATY,KPIR,KMBG Low level wind shear will be possible overnight, given the strong southerly winds that are forecast to persist into Sunday. Strong to severe thunderstorms are probable, including very strong winds. Storms clear off by morning to reset the atmosphere for potentially another round of strong storms on Sunday afternoon and evening. ***Construction to improve the taxiway for runway 13 at the KPIR terminal may cause an occasional temporary visibility reduction due to blowing dust (bldu), mainly during daytime hours UFN.*** && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && UPDATE...Dorn SHORT TERM...Parkin LONG TERM...SD AVIATION...Dorn
Hazardous Weather Outlook National Weather Service Aberdeen SD 342 AM CDT Sat Jun 6 2020 MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-070845- Traverse-Big Stone-Corson-Campbell-McPherson-Brown-Marshall-Roberts- Walworth-Edmunds-Day-Dewey-Potter-Faulk-Spink-Clark-Codington-Grant- Hamlin-Deuel-Stanley-Sully-Hughes-Hyde-Hand-Jones-Lyman-Buffalo- 342 AM CDT Sat Jun 6 2020 /242 AM MDT Sat Jun 6 2020/ This Hazardous Weather Outlook is for west central Minnesota, central South Dakota, north central South Dakota and northeast South Dakota. .DAY ONE...Today and tonight. A couple of rounds of thunderstorm activity expected for the region through the weekend. Initially, weak storms that are currently developing west river will move across the northern half of the state. Not anticipating widespread severe weather with this activity however. Another round of storm development is expected west river this afternoon and pushes into central South Dakota this evening and into eastern South Dakota and western Minnesota overnight. This round of storms will form in an environment that will favor strong winds and large hail, with an isolated tornado or two possible. Heavy rain potential also exists with this wave of storms. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Another round of storms will form in the afternoon Sunday, again with a large hail, strong wind threat, in addition to an isolated tornado or two potential. The focus for this round of storms is mainly from the James valley and points east. Heavy rain potential also exists with this wave of storms. .SPOTTER INFORMATION STATEMENT... Spotter activation will likely be needed. Weather spotters are encouraged to submit reports to the National Weather Service in Aberdeen. The public can submit reports on our web page, Facebook page, or our Twitter feed. Connelly
The Rapid City radar (KUDX), 159 km away, was scanning. The volume nearest the first event began at 02:43 UTC.
12 thunderstorm wind. Local standard time, as filed.
Estimated seventy mph winds tore part of a metal roof off of a building.
A semi was blown off Interstate-90 and into the median.
Sixty mph wind was estimated.
Estimated sixty mph winds brought some tree limbs down and took some shingles off the house.
A wind gust of 94 mph brought down many large tree branches.
Eighty mph winds were estimated by a storm chaser.
An estimated sixty mph wind downed an olive tree.
An estimated eighty mph wind destroyed a ten unit storage shed. The back wall was pushed over with metal spread downwind up to a quarter mile. The boats inside were not moved.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2020Every state in 2020This day in weather historyWarnings in South Dakota, June 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 897988, 898008, 898017, 897996, 898009, 898010, 898011, 898012, 898013, 898014, 898015, 898007.