Alert archive / South Dakota / Tornado Warnings in 2026
Tornado Warning 6, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at May 17, 2026, 4:27 PM CDT for Lincoln County, Minnehaha County, South Dakota; Lyon County, Iowa. It was in force for 48 min. 7 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, 4:27 PM CDT (21:27 UTC)
- Expired
- May 17, 2026, 5:15 PM CDT
- In force
- 48 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.75 in
Counties Lyon County, IA, Lincoln County, SD, Minnehaha County, SD
The radar
The Sioux Falls radar (KFSD), 16 km from the middle of the area, began a volume at 21:29 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, 4:36 PM CDT | HAIL 1 | 4 Nw Harrisburg, SD | Report from 85th and Western of quarter size hail. |
| May 17, 4:36 PM CDT | HAIL 1 | 4 Nw Harrisburg, SD | Report from 85th and Western of quarter size hail. |
| May 17, 4:38 PM CDT | HAIL 1 | Tea, SD | |
| May 17, 4:38 PM CDT | HAIL 1 | Tea, SD | |
| May 17, 4:45 PM CDT | TSTM WND DMG | 2 Se Sioux Falls, SD | Large tree limbs down. |
| May 17, 4:47 PM CDT | HAIL 1.5 | 4 Sse Sioux Falls, SD | |
| May 17, 4:47 PM CDT | HAIL 1.5 | 4 Sse Sioux Falls, SD |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
Did it verify
Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this tornado warning while it was in force. That is not proof nothing happened: reports are thin where few people live.
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
Aberdeen, SD (KABR), launched 12:00Z, 9.5 hours before the alert went out and 210 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2103 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 372 m²/s²
- 0-3 km storm-relative helicity
- 379 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
096
WFUS53 KFSD 172127
TORFSD
IAC119-SDC083-099-172215-
/O.NEW.KFSD.TO.W.0006.260517T2127Z-260517T2215Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
427 PM CDT Sun May 17 2026
The National Weather Service in Sioux Falls has issued a
* Tornado Warning for...
Northwestern Lyon County in northwestern Iowa...
Southeastern Minnehaha County in southeastern South Dakota...
Northern Lincoln County in southeastern South Dakota...
* Until 515 PM CDT.
* At 427 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Tea, or 9 miles southwest of Sioux Falls, moving
east at 40 mph.
HAZARD...Tornado.
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 dangerous storm will be near...
Sioux Falls, Harrisburg, and Tea around 430 PM CDT.
Lake Alvin State Recreation Area around 435 PM CDT.
Rowena around 440 PM CDT.
Larchwood around 445 PM CDT.
Other locations in the path of this tornadic thunderstorm include
Valley Springs.
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 4338 9692 4350 9690 4358 9646 4339 9644
TIME...MOT...LOC 2127Z 256DEG 36KT 4344 9686
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Weisser3 follow-up statements
558
WWUS53 KFSD 172144
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
444 PM CDT Sun May 17 2026
IAC119-SDC083-099-172215-
/O.CON.KFSD.TO.W.0006.000000T0000Z-260517T2215Z/
Lyon IA-Minnehaha SD-Lincoln SD-
444 PM CDT Sun May 17 2026
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 515 PM CDT FOR
NORTHWESTERN LYON...SOUTHEASTERN MINNEHAHA AND NORTHEASTERN LINCOLN
COUNTIES...
At 444 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Lake Alvin State Recreation Area, or near Sioux
Falls, moving east at 35 mph.
HAZARD...Tornado and quarter size hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
Locations impacted include...
Sioux Falls, Larchwood, Valley Springs and Rowena.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4339 9676 4352 9680 4358 9646 4339 9644
TIME...MOT...LOC 2144Z 248DEG 28KT 4349 9666
TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
$$
Weisser389
WWUS53 KFSD 172201
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
501 PM CDT Sun May 17 2026
SDC083-172211-
/O.CAN.KFSD.TO.W.0006.000000T0000Z-260517T2215Z/
Lincoln SD-
501 PM CDT Sun May 17 2026
...THE TORNADO WARNING FOR NORTHEASTERN LINCOLN COUNTY 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...southwestern Minnesota...and southeastern South Dakota.
&&
LAT...LON 4343 9656 4355 9659 4358 9646 4339 9644
TIME...MOT...LOC 2201Z 257DEG 31KT 4351 9650
$$
IAC119-SDC099-172215-
/O.CON.KFSD.TO.W.0006.000000T0000Z-260517T2215Z/
Lyon IA-Minnehaha SD-
501 PM CDT Sun May 17 2026
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 515 PM CDT FOR
NORTHWESTERN LYON AND SOUTHEASTERN MINNEHAHA COUNTIES...
At 501 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Rowena, or 11 miles east of Sioux Falls, moving east
at 35 mph.
HAZARD...Tornado and quarter size hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
Locations impacted include...
Larchwood, Valley Springs, and Rowena.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4343 9656 4355 9659 4358 9646 4339 9644
TIME...MOT...LOC 2201Z 257DEG 31KT 4351 9650
TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
$$
Weisser060 WWUS53 KFSD 172208 SVSFSD Severe Weather Statement National Weather Service Sioux Falls SD 508 PM CDT Sun May 17 2026 IAC119-SDC099-172218- /O.EXP.KFSD.TO.W.0006.000000T0000Z-260517T2215Z/ Lyon IA-Minnehaha SD- 508 PM CDT Sun May 17 2026 ...THE TORNADO WARNING FOR NORTHWESTERN LYON AND SOUTHEASTERN MINNEHAHA COUNTIES WILL EXPIRE AT 515 PM CDT... The storm which prompted the warning has moved out of the area. Therefore, the warning will be allowed to expire. However, gusty winds and heavy rain are still possible with this thunderstorm. A Tornado Watch remains in effect until 1000 PM CDT for northwestern Iowa...southwestern Minnesota...and southeastern South Dakota. && LAT...LON 4343 9656 4355 9659 4358 9646 4339 9644 TIME...MOT...LOC 2208Z 256DEG 36KT 4353 9641 $$ Weisser
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, 1:20 PM CDT, 3 hours 7 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, 1:20 PM CDT, 3 hours 7 minutes before
Area Forecast Discussion National Weather Service Sioux Falls SD Issued by National Weather Service Lincoln IL 120 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 /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1248 PM CDT Sun May 17 2026 Showers and storms move through the region this afternoon into tonight. Intermittent MVFR/IFR conditions will be possible throughout this timeframe, especially in heavier rain. TSRA was included at least in PROB30 groups, but is expected to be the dominant weather type at times. Widespread MVFR/IFR cigs setting in overnight for much of Monday. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && DISCUSSION...ILX/25 AVIATION...DYE
Hazardous weather outlook, May 17, 1:29 PM CDT, 2 hours 58 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, 3:54 PM CDT, 33 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
354 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0338 PM Tstm Wnd Gst 7 ESE Menno 43.21N 97.45W
05/17/2026 M81 MPH Hutchinson SD Mesonet
Mesonet station MNMS2 Menno 7ESE (SD
Mesonet).
&&
akLocal storm report, May 17, 3:55 PM CDT, 32 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
355 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0315 PM Tstm Wnd Dmg 2 S Tyndall 42.96N 97.86W
05/17/2026 Bon Homme SD Trained Spotter
65 to 70 mph downed small trees. Quarter
sized hail also occurred.
&&
THLocal storm report, May 17, 3:58 PM CDT, 29 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
358 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0342 PM Tstm Wnd Gst 5 S Freeman 43.28N 97.42W
05/17/2026 M82 MPH Hutchinson SD Mesonet
Mesonet station 163 SD RWIS Freeman.
&&
akLocal storm report, May 17, 3:59 PM CDT, 28 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
359 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0347 PM Tstm Wnd Gst 9 W Hurley 43.26N 97.27W
05/17/2026 E60 MPH Turner SD Trained Spotter
Spotter estimated 50-60 mph winds along with
half dollar size hail.
&&
MMLocal storm report, May 17, 4:07 PM CDT, 20 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
407 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0342 PM Tstm Wnd Dmg 8 S Freeman 43.24N 97.42W
05/17/2026 Hutchinson SD Emergency Mngr
Damage to large road signs near intersection
of Hwy 18/81.
&&
akLocal storm report, May 17, 4:27 PM CDT, 0 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
427 PM CDT Sun May 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0417 PM Hail 2 W Lennox 43.35N 96.93W
05/17/2026 M1.00 Inch Turner SD Public
Quarter size hail along with estimated 40-50
mph winds reported.
&&
MMThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 17, 1:10 AM CDT | Flash Flood Warning | FSD | Union | 4 hr |
| May 17, 1:09 PM CDT | Severe Thunderstorm Warning | FSD | Gregory | 51 min |
| May 17, 2:10 PM CDT | Severe Thunderstorm Warning | FSD | Charles Mix, Gregory | 50 min |
| May 17, 2:15 PM CDT | Severe Thunderstorm Warning | FSD | Aurora, Brule, Charles Mix, Douglas | 45 min |
| May 17, 2:49 PM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Hutchinson, Yankton | 41 min |
| May 17, 2:50 PM CDT | Tornado Warning | FSD | Bon Homme, Charles Mix, Hutchinson | 40 min |
| May 17, 3:23 PM CDT | Tornado Warning | FSD | Hutchinson, Turner, Yankton | 52 min |
| May 17, 3:28 PM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Clay, Hutchinson, Turner, Yankton | 47 min |
| May 17, 3:35 PM CDT | Tornado Warning | FSD | Hutchinson, Turner | 28 min |
| May 17, 3:59 PM CDT | Severe Thunderstorm Warning | FSD | Lincoln, Turner | 46 min |
| May 17, 4:18 PM CDT | Severe Thunderstorm Warning | FSD | Lincoln, Minnehaha, Turner | 42 min |
| May 17, 4:56 PM CDT | Severe Thunderstorm Warning | FSD | Minnehaha | 49 min |
| May 16, 11:14 PM CDT | Severe Thunderstorm Warning | FSD | Clay, O'Brien | 16 min |
| May 17, 5:43 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Osceola | 62 min |
| May 17, 5:56 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, O'Brien, Osceola, Sioux | 27 min |
| May 17, 6:30 PM CDT | Severe Thunderstorm Warning | FSD | Dickinson, Osceola | 75 min |
| May 17, 6:33 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Sioux | 57 min |
Nearby
Tornado Warnings in South Dakota, 2026Tornado 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.