Alert archive / Nebraska / Mesoscale Discussions in 2026

Mesoscale Discussion 749

May 17, 20264 states

The Storm Prediction Center issued this mesoscale discussion at May 17, 2026, 1:11 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 17, 2026, 1:11 PM CDT (18:11 UTC)
Expired: May 17, 2026, 3:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...tornado watch likely
Chance of a watch: 95%

All 56 counties

Cherokee County, IA, Harrison County, IA, Ida County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Antelope County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Burt County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Garfield County, NE, Holt County, NE, Keya Paha County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Platte County, NE, Rock County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, Aurora County, SD, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 98 km from the middle of the area, began a volume at 18:11 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 6.2 hours before the alert went out and 187 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1204 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: -21 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
May 17, 1:42 PM CDT	Tornado Watch	SPC	Buena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 6 more	8 hr
May 17, 3:16 PM CDT	Tornado Watch	SPC	Fremont, Harrison, Mills, Montgomery, Page, Pottawattamie and 1 more	8 hr
May 17, 3:31 PM CDT	Mesoscale Discussion	SPC	Lyon, O'Brien, Osceola, Sioux	89 min
May 17, 5:45 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Cerro Gordo, Clay, Emmet, Floyd, Franklin and 10 more	60 min
May 17, 6:12 PM CDT	Tornado Watch	SPC	Bremer, Butler, Cerro Gordo, Chickasaw, Emmet, Fayette and 13 more	6 hr
May 17, 6:53 PM CDT	Mesoscale Discussion	SPC	Cherokee, Crawford, Fremont, Harrison, Ida, Mills and 6 more	67 min
May 16, 7:01 PM CDT	Mesoscale Discussion	SPC	Adams, Buffalo, Clay, Dundy, Fillmore, Franklin and 14 more	119 min
May 16, 8:36 PM CDT	Mesoscale Discussion	SPC	Gage, Jefferson, Johnson, Thayer	114 min
May 16, 10:15 PM CDT	Mesoscale Discussion	SPC	Adams, Cass, Clay, Fillmore, Franklin, Gage and 13 more	2 hr
May 17, 12:33 AM CDT	Mesoscale Discussion	SPC	Gage, Johnson, Nemaha, Pawnee, Richardson	87 min
May 17, 3:08 AM CDT	Mesoscale Discussion	SPC	Boone, Buffalo, Custer, Dawson, Greeley, Hall and 7 more	97 min
May 17, 11:58 AM CDT	Mesoscale Discussion	SPC	Blaine, Boyd, Brown, Cherry, Garfield, Holt and 5 more	92 min
May 17, 2:45 PM CDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Butler, Cass, Clay and 33 more	60 min
May 17, 3:08 PM CDT	Mesoscale Discussion	SPC	Chase, Dundy	3 hr
May 17, 4:58 PM CDT	Severe Thunderstorm Watch	SPC	Dundy, Hitchcock	3 hr
May 17, 5:13 PM CDT	Mesoscale Discussion	SPC	Adams, Butler, Clay, Colfax, Dodge, Fillmore and 18 more	62 min

Nearby

Mesoscale Discussions in Nebraska, 2026 Mesoscale Discussions in South Dakota, 2026 Mesoscale Discussions in Iowa, 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.