Alert archive / South Dakota / Mesoscale Discussions in 2026

Mesoscale Discussion 985

June 4, 2026Boyd County, Keya Paha County, Nebraska; 15 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 4, 2026, 11:39 PM CDT for Boyd County, Keya Paha County, Nebraska; 15 counties in South Dakota. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Jun 4, 2026, 11:39 PM CDT (04:39 UTC)
Expired: Jun 5, 2026, 1:15 AM CDT
In force: 96 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 273

Counties Boyd County, NE, Keya Paha County, NE, Aurora County, SD, Beadle County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hand County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, McCook County, SD, Miner County, SD, Sanborn County, SD

The radar

The Sioux Falls radar (KFSD), 150 km from the middle of the area, began a volume at 04:41 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

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 4.7 hours before the alert went out and 320 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: 1040 J/kg
Mixed-layer CIN: -85 J/kg
Mixed-layer LCL: 1760 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -16 m²/s²
0-3 km storm-relative helicity: 99 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.5

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 4, 9:47 PM CDT	Mesoscale Discussion	SPC	Boyd, Cherry, Keya Paha	118 min
Jun 5, 3:55 PM CDT	Mesoscale Discussion	SPC	Adams, Buffalo, Butler, Cass, Clay, Dodge and 29 more	2 hr
Jun 5, 5:48 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Buffalo, Butler, Cass, Clay, Douglas and 30 more	8 hr
Jun 5, 6:46 PM CDT	Mesoscale Discussion	SPC	Adams, Buffalo, Butler, Cass, Clay, Colfax and 29 more	89 min
Jun 4, 7:31 PM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Bennett, Brookings, Brule, Buffalo and 23 more	119 min
Jun 5, 1:12 PM CDT	Mesoscale Discussion	SPC	Grant, Roberts	93 min

Nearby

Mesoscale Discussions in South Dakota, 2026 Mesoscale Discussions in Nebraska, 2026 Every mesoscale discussion in 2026

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.