Alert archive / South Dakota / Severe Thunderstorm Warnings in 2025

Severe Thunderstorm Warning 239, NWS Aberdeen, SD

August 17, 2025Brown County, South Dakota

NWS Aberdeen, SD issued this severe thunderstorm warning at Aug 17, 2025, 7:16 AM CDT for Brown County, South Dakota. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 17, 2025, 7:16 AM CDT (12:16 UTC)
Expired: Aug 17, 2025, 8:00 AM CDT
In force: 44 min
Issued by: NWS Aberdeen, SD
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Brown County, SD

The radar

The Aberdeen radar (KABR), 16 km from the middle of the area, began a volume at 12:15 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 0.3 hours before the alert went out and 77 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1722 J/kg
Mixed-layer CIN: -179 J/kg
Mixed-layer LCL: 736 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 208 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Aug 17, 1:47 AM CDT, 5 hours 29 minutes earlier. Its key messages:

Marginal risk (level 1 of 5) for severe weather from south central SD into southern areas of northeast SD and west central MN today. Main threats are for severe wind gusts and hail. -There is also a slight risk for excessive rainfall over northeastern SD and west central MN today into Monday morning.
There is another marginal risk (level 1 of 5) for severe weather over central SD Monday. Main threats are for severe wind gusts and hail.

Area forecast discussion, Aug 17, 1:47 AM CDT, 5 hours 29 minutes before

Area Forecast Discussion
National Weather Service Aberdeen SD
147 AM CDT Sun Aug 17 2025

.KEY MESSAGES...

- Marginal risk (level 1 of 5) for severe weather from south
  central SD into southern areas of northeast SD and west central
  MN today. Main threats are for severe wind gusts and hail.

-There is also a slight risk for excessive rainfall over
 northeastern SD and west central MN today into Monday morning.

- There is another marginal risk (level 1 of 5) for severe weather over
  central SD Monday. Main threats are for severe wind gusts and
  hail.

&&

.DISCUSSION...
Issued at 146 AM CDT Sun Aug 17 2025

As of 7z, severe and near-severe storms are moving from western SD
into central SD. Additionally, there are storms developing along the
boundary over southern SD that are trying to work their way into
northeastern SD. The line over central SD looks to continue moving
east while the other line moves northeast through SD into the
morning hours.

A parked frontal boundary continues to sit over southern SD though
the day today. This boundary looks to continue to develop
precipitation and storms through the day today and into the evening.
The instability and moisture is there for storms to continue to
develop in this precipitation. Increased shear along the frontal
boundary this afternoon over eastern SD could lead to the potential
for a tornado or two. For storms that have moved away from the
front, the main threat will be mainly for severe winds and a smaller
threat for quarter sized hail. Additionally, with storms moving over
the same area there is a threat for flooding, with WPC's excessive
rainfall outlook highlighting a slight risk of flooding over eastern
SD. On another note, there will be increasing elevated smoke moving
in this afternoon over central and parts of northeastern SD. This
smoke look to stay mostly elevated, though some smoke might be near
the surface west of the Missouri River.

The frontal boundary looks to move south during the day Monday. This
will shift the threat for severe storms to the south. The lee of the
Rockies trough will still have the potential for storms to develop
over western SD and move east. Instability over central SD could
support storms moving over central SD Monday evening. The
instability does start to decrease once moving east of the Missouri
River. This then reduces the risk for severe storms over
northeastern SD. Because of this, SPC has a marginal risk for severe
storms over central SD, with the main threats being severe wind and
hail.

Monday evening, the upper and mid levels of the atmosphere are
forecasting a high pressure to start developing over AZ and NM. This
high pressure will help to create an upper and mid level ridge that
moves over western areas of SD though the end of the work week. Some
weaker areas of surface high pressure try to develop over central
and eastern SD through Thursday, reducing the chances for
precipitation moving over the state. Temperatures during this time
will increase, leading to higher temperatures over central SD. Max
temperatures could get into the low to upper 90s through the mid and
end of the work week over central SD and low to upper 80s over
northeastern SD.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1209 AM CDT Sun Aug 17 2025

Terminals KABR,KATY,KPIR,KMBG

Showers and storms will be moving through the sites tonight, causing
VFR conditions to become MVFR and IFR. Some of these storms could be
severe, with strong wind gusts and the potential for hail. The
threat for storms and showers exists into the early morning hours
for most sites, with the threat forecast to continue for KATY into
the afternoon.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

DISCUSSION...12
AVIATION...12

Hazardous weather outlook, Aug 17, 4:15 AM CDT, 3 hours 1 minute before

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In the hours before

Special weather statement, Aug 17, 5:09 AM CDT, 2 hours 7 minutes before

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Special weather statement, Aug 17, 5:20 AM CDT, 1 hour 56 minutes before

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Special weather statement, Aug 17, 5:50 AM CDT, 1 hour 26 minutes before

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Special weather statement, Aug 17, 6:32 AM CDT, 44 minutes before

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Special weather statement, Aug 17, 6:56 AM CDT, 20 minutes before

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Special weather statement, Aug 17, 7:09 AM CDT, 7 minutes before

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The office that day

Everything else NWS Aberdeen, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 17, 2:12 AM CDT	Severe Thunderstorm Warning	ABR	Corson, Dewey	93 min
Aug 17, 3:59 AM CDT	Special Weather Statement	ABR	Campbell, Potter, Sully, Walworth	61 min
Aug 17, 4:08 AM CDT	Severe Thunderstorm Warning	ABR	Campbell, Corson, Dewey, Potter, Walworth	52 min
Aug 17, 5:09 AM CDT	Special Weather Statement	ABR	McPherson	36 min
Aug 17, 5:20 AM CDT	Special Weather Statement	ABR	McPherson	40 min
Aug 17, 5:50 AM CDT	Special Weather Statement	ABR	McPherson	40 min
Aug 17, 6:32 AM CDT	Special Weather Statement	ABR	Edmunds	28 min
Aug 17, 6:56 AM CDT	Special Weather Statement	ABR	Edmunds	34 min
Aug 17, 7:09 AM CDT	Special Weather Statement	ABR	Brown	21 min
Aug 17, 8:01 AM CDT	Special Weather Statement	ABR	Marshall	14 min
Aug 17, 8:31 AM CDT	Special Weather Statement	ABR	Marshall	29 min
Aug 17, 8:43 AM CDT	Severe Thunderstorm Warning	ABR	Day, Roberts	47 min
Aug 17, 8:56 AM CDT	Severe Thunderstorm Warning	ABR	Marshall	23 min
Aug 17, 9:12 AM CDT	Special Weather Statement	ABR	Roberts	33 min
Aug 17, 9:44 AM CDT	Areal Flood Warning	ABR	Day	6 hr
Aug 17, 1:39 PM CDT	Areal Flood Warning	ABR	Marshall	29 hr
Aug 17, 4:14 PM CDT	Areal Flood Warning	ABR	Deuel, Hamlin	42 hr

Nearby

Severe Thunderstorm Warnings in South Dakota, 2025 Every severe thunderstorm warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.