Alert archive / Iowa / Tornado Warnings in 2026
Tornado Warning 14, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at May 17, 2026, 8:26 PM CDT for 4 counties in Iowa. It was in force for 28 min. 5 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- May 17, 2026, 8:26 PM CDT (01:26 UTC)
- Expired
- May 17, 2026, 8:54 PM CDT
- In force
- 28 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 1.0 in
Counties Buena Vista County, IA, Cherokee County, IA, Clay County, IA, O'Brien County, IA
The radar
The Sioux Falls radar (KFSD), 125 km from the middle of the area, began a volume at 01:28 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 17, 8:26 PM CDT | TORNADO | 3 Ne Meriden, IA | Storm chasers reported a brief tornado on the ground 2 to 3 minutes. Time and location confirmed with radar. |
| May 17, 8:26 PM CDT | TORNADO | 3 Ne Meriden, IA | Storm chasers reported a brief tornado on the ground 2 to 3 minutes. Time and location confirmed with radar. |
| May 17, 8:29 PM CDT | TSTM WND GST 62 | 6 N Cleghorn, IA | Via personal weather station. Exact time estimated via radar. |
| May 17, 8:29 PM CDT | TSTM WND GST 62 | 6 N Cleghorn, IA | Via personal weather station. Exact time estimated via radar. |
| May 17, 8:31 PM CDT | TORNADO | 5 Wsw Royal, IA | Social media video relayed by emergency manager of brief tornado. Location estimated. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
Did it verify
Verified. The Iowa Environmental Mesonet's Cow matched 2 storm reports to this tornado warning; the first came 0 minutes after it went out.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 17, 1:42 PM CDT | Tornado Watch | SPC | 8 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.4 hours before the alert went out and 191 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.
- Mixed-layer CAPE
- 2478 J/kg
- Mixed-layer CIN
- -15 J/kg
- Mixed-layer LCL
- 1258 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 178 m²/s²
- 0-3 km storm-relative helicity
- 298 m²/s²
- Significant tornado parameter
- 2.0
- Supercell composite
- 17.9
The text
As transmitted.
845
WFUS53 KFSD 180126
TORFSD
IAC021-035-041-141-180215-
/O.NEW.KFSD.TO.W.0014.260518T0126Z-260518T0215Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
826 PM CDT Sun May 17 2026
The National Weather Service in Sioux Falls has issued a
* Tornado Warning for...
Northeastern Cherokee County in northwestern Iowa...
Northwestern Buena Vista County in northwestern Iowa...
Southwestern Clay County in northwestern Iowa...
Southeastern O'Brien County in northwestern Iowa...
* Until 915 PM CDT.
* At 826 PM CDT, severe thunderstorms capable of producing both
tornadoes and extensive straight line wind damage were located near
Cleghorn, or 7 miles northwest of Cherokee, moving northeast at 40
mph.
HAZARD...Tornado and quarter size hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* These dangerous storms will be near...
Sutherland and Larrabee around 830 PM CDT.
Peterson around 840 PM CDT.
Linn Grove around 845 PM CDT.
Other locations in the path of this tornadic thunderstorm include
Sioux Rapids.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4281 9564 4291 9574 4313 9539 4288 9506
TIME...MOT...LOC 0126Z 242DEG 36KT 4283 9564
TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
$$
BP2 follow-up statements
212
WWUS53 KFSD 180144
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
844 PM CDT Sun May 17 2026
IAC021-035-141-180154-
/O.CAN.KFSD.TO.W.0014.000000T0000Z-260518T0215Z/
Cherokee IA-Buena Vista IA-O'Brien IA-
844 PM CDT Sun May 17 2026
...THE TORNADO WARNING FOR NORTHEASTERN CHEROKEE...NORTHWESTERN BUENA
VISTA AND SOUTHEASTERN O'BRIEN COUNTIES IS CANCELLED...
The tornadic thunderstorm which prompted the warning has moved out
of the warned area. Therefore, the warning has been cancelled.
A Tornado Watch remains in effect until 1000 PM CDT for northwestern
Iowa.
&&
LAT...LON 4291 9510 4291 9539 4313 9539
TIME...MOT...LOC 0144Z 258DEG 54KT 4298 9526
$$
IAC041-180215-
/O.CON.KFSD.TO.W.0014.000000T0000Z-260518T0215Z/
Clay IA-
844 PM CDT Sun May 17 2026
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 915 PM CDT FOR
SOUTHWESTERN CLAY COUNTY...
At 844 PM CDT, a severe squall line capable of producing both
tornadoes and extensive straight line wind damage was located near
Royal, or 12 miles southwest of Spencer In Clay County, moving east
at 60 mph.
HAZARD...Tornado and quarter size hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
This tornadic thunderstorm will remain over mainly rural areas of
southwestern Clay County.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4291 9510 4291 9539 4313 9539
TIME...MOT...LOC 0144Z 258DEG 54KT 4298 9526
TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
$$
BP679 WWUS53 KFSD 180154 SVSFSD Severe Weather Statement National Weather Service Sioux Falls SD 854 PM CDT Sun May 17 2026 IAC041-180204- /O.CAN.KFSD.TO.W.0014.000000T0000Z-260518T0215Z/ Clay IA- 854 PM CDT Sun May 17 2026 ...THE TORNADO WARNING FOR SOUTHWESTERN CLAY COUNTY IS CANCELLED... The storm which prompted the warning has moved out of the area. Therefore, the warning has been cancelled. A Tornado Watch remains in effect until 1000 PM CDT for northwestern Iowa. To report severe weather, contact your nearest law enforcement agency. They will relay your report to the National Weather Service Sioux Falls. && LAT...LON 4291 9510 4291 9539 4313 9539 TIME...MOT...LOC 0151Z 242DEG 36KT 4303 9513 $$ BP
What forecasters said that day
The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sioux Falls, SD wrote its last area forecast discussion before this tornado warning went out at May 17, 6:53 PM CDT, 1 hour 33 minutes earlier. Its key messages:
- There is high confidence that severe thunderstorms will develop this afternoon and evening, producing large hail, destructive straight-line winds, and a few tornadoes. An Enhanced Risk (level 3 of 5) of severe storms is in place.
- A transitioning storm mode will shift hazards from large hail and tornadoes initially, to widespread wind damage as an intense line of storms tracks east of Interstate 29 this evening.
- A lower risk of severe weather exists late Monday afternoon and evening, mainly over northwest IA, before quieter weather moves in for the mid-week period.
Area forecast discussion, May 17, 6:53 PM CDT, 1 hour 33 minutes before
Area Forecast Discussion National Weather Service Sioux Falls SD Issued by National Weather Service Rapid City SD 653 PM CDT Sun May 17 2026 .KEY MESSAGES... - There is high confidence that severe thunderstorms will develop this afternoon and evening, producing large hail, destructive straight-line winds, and a few tornadoes. An Enhanced Risk (level 3 of 5) of severe storms is in place. - A transitioning storm mode will shift hazards from large hail and tornadoes initially, to widespread wind damage as an intense line of storms tracks east of Interstate 29 this evening. - A lower risk of severe weather exists late Monday afternoon and evening, mainly over northwest IA, before quieter weather moves in for the mid-week period. && .DISCUSSION... Issued at 120 PM CDT Sun May 17 2026 The short-term convective outlook presents a highly volatile spring severe weather setup. Latest surface analysis shows a complex pattern, anchored by a strong 994 mb low over northwest KS. An inverted trough extended north of the low through central SD, while a well-defined warm front stretched northeast of the low into east central NE. A weaker low was also noted in north central NE. Visible satellite imagery revealed stable wave clouds advancing northeast over far northeast NE and extreme SE SD, ahead of the advancing warm front. Regional radar imagery showed a complex of strong to severe storms over north central NE. This storm complex is forecast by short range guidance to continue tracking east this afternoon, intensifying as interacts with the richer low- level moisture pool near and south of the warm front. Moderate to strong instability will be in place over the southern to eastern CWA by late afternoon with MLCAPE nearing 3000 J/kg. In addition, deep layer shear will increase to around 50 kt, coincident with a mid level speed max ejecting from the deep upper trough to our west. As the system evolves over the next several hours, it appears the ingredients for a significant severe weather event will be most favored over the southern to eastern CWA. Ahead of the main convective line, some CAMs show supercell development along the northward advancing warm front. These storms would present a risk of very large hail (2"+) and tornadoes. Given the amount of low level SRH/curved hodographs present, a couple strong tornadoes are possible. The convective cluster currently entering our far southwest CWA should strengthen as it shifts east, with an initial hail and tornado threat transitioning to a damaging straight line wind threat (70+ MPH) as it grows upscale into a squall line/QLCS. Some line-embedded QLCS tornadoes are possible, especially for any line segments that become oriented north/south or northwest/southeast, given southwesterly 0-3 km shear vectors. Timing from latest high-res guidance suggests this activity exits to the east of our CWA late this evening. Precipitation amounts will vary significantly based on convective tracks, though NBM guidance and HREF probability match mean fields project a widespread 0.50 to 1.50 inches of rainfall, particularly across northwest Iowa and southwest Minnesota. On Monday, the cold front finally pushes into the area. Instability and shear are forecast to be much lower than today, however, there will be a conditional risk of severe storms over the eastern CWA during the late afternoon to evening, if the airmass can destabilize sufficiently ahead of the front. SPC's Day 2 outlook indicates as Marginal Risk (level 1 of 5), for our MN and IA counties. Behind the departing upper wave, quasi-zonal flow sets up for Tuesday and Wednesday, yielding quiet conditions and seasonally cool high temperatures moderating from the upper 50s Tuesday to mid-upper 60s Wednesday. The next upper wave moves in for the Thursday to Friday period, however Gulf moisture remains cutoff ahead of this system. Evaluating the ECMWF Extreme Forecast Index (EFI) reveals no significant climatological anomalies for precipitation or wind across the upper Midwest during this period, reinforcing the the idea of a low-impact system for our area. The current forecast sticks closely to the NBM consensus, maintaining broad 20-30 percent probabilities for light rain for late Thursday into Saturday. By late this week and especially this weekend, temperatures will embark on a steady upward trajectory, as the mid level flow backs west, then southwest. The Climate Prediction Center (CPC) 6-10 day outlook favors above-normal temperatures across the Northern Plains and Upper Midwest, which supports blended guidance high temperatures reaching well into the 80s on Sunday. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 650 PM CDT Sun May 17 2026 Showers and storms will continue to move eastward into MN through the evening hours, the forecast area should be largely clear of shower/storm activity after ~05z. Intermittent MVFR/IFR conditions in heavy rainfall as well as hail and strong winds will accompany the strongest storms. Widespread MVFR/IFR cigs will set in overnight and persist through much of Monday. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && DISCUSSION...ILX/25 AVIATION...Wong
Hazardous weather outlook, May 17, 1:29 PM CDT, 6 hours 57 minutes before
Hazardous Weather Outlook National Weather Service Sioux Falls SD Issued by National Weather Service Lincoln IL 129 PM CDT Sun May 17 2026 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-NEZ013-014-SDZ038>040-050-052>071-181830- Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee- Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson- Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory- Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook- Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton- Union- 129 PM CDT Sun May 17 2026 This Hazardous Weather Outlook is for northwest Iowa, west central Iowa, southwest Minnesota, northeast Nebraska, central South Dakota, east central South Dakota, south central South Dakota and southeast South Dakota. .DAY ONE...This afternoon and tonight. A significant severe weather event is possible this afternoon and evening. Very large hail, damaging wind gusts, and tornadoes are all possible. If you have outdoor plans know where your nearest shelter is located. Please ensure you have multiple ways to receive warnings. Have a plan to take shelter and act immediately if your area comes under a severe weather warning. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Strong to severe storms are possible again Monday afternoon and evening, particularly over northwest Iowa and southwest Minnesota. .SPOTTER INFORMATION STATEMENT... Spotter activation will likely be needed this afternoon and evening.
In the hours before
Local storm report, May 17, 7:56 PM CDT, 30 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
756 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0749 PM Tstm Wnd Gst Moville 42.49N 96.06W
05/17/2026 M63 MPH Woodbury IA Public
Via personal weather station.
&&
akLocal storm report, May 17, 8:08 PM CDT, 18 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
808 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0757 PM Tornado 5 NW Kingsley 42.63N 96.04W
05/17/2026 Plymouth IA Fire Dept/Rescue
Kingsley Fire reported brief tornado near
C60 and Pioneer Ave.
&&
PRLocal storm report, May 17, 8:18 PM CDT, 8 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
818 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0754 PM Tstm Wnd Gst 4 W Correctionville 42.48N 95.86W
05/17/2026 E74 MPH Woodbury IA Public
Via personal weather station. Exact time
estimated via radar.
&&
akLocal storm report, May 17, 8:19 PM CDT, 7 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
819 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0756 PM Tstm Wnd Gst 3 NE Moville 42.52N 96.03W
05/17/2026 M75 MPH Woodbury IA Public
Via personal weather station. Exact time
estimated via radar.
&&
akLocal storm report, May 17, 8:20 PM CDT, 6 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
820 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0750 PM Tstm Wnd Gst Moville 42.49N 96.06W
05/17/2026 M77 MPH Woodbury IA Public
Via personal weather station. Exact time
estimated via radar.
&&
akLocal storm report, May 17, 8:24 PM CDT, 2 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
824 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0757 PM Tstm Wnd Gst 1 SW Pierson 42.53N 95.88W
05/17/2026 M74 MPH Woodbury IA Public
Via personal weather station. Exact time
estimated via radar.
&&
akThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 17, 7:20 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Sioux | 28 min |
| May 17, 7:20 PM CDT | Severe Thunderstorm Warning | FSD | O'Brien, Osceola | 26 min |
| May 17, 7:26 PM CDT | Tornado Warning | FSD | Woodbury | 49 min |
| May 17, 7:32 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida, Plymouth, Woodbury | 58 min |
| May 17, 7:47 PM CDT | Tornado Warning | FSD | Cherokee, Plymouth, Woodbury | 43 min |
| May 17, 8:00 PM CDT | Severe Thunderstorm Warning | FSD | O'Brien, Osceola, Plymouth, Sioux | 45 min |
| May 17, 8:03 PM CDT | Flash Flood Warning | FSD | Plymouth, Sioux | 3 hr |
| May 17, 8:21 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Clay, Dickinson, Ida, O'Brien and 3 more | 54 min |
| May 17, 8:48 PM CDT | Tornado Warning | FSD | Clay, Dickinson | 27 min |
| May 17, 8:54 PM CDT | Tornado Warning | FSD | Clay, Dickinson | 51 min |
| May 18, 5:11 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida, Plymouth, Woodbury | 49 min |
| May 18, 5:48 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Clay, O'Brien | 42 min |
| May 18, 6:08 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Sioux | 37 min |
Nearby
Tornado Warnings in Iowa, 2026Every tornado warning in 2026Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.