Alert archive / South Dakota / Tornado Warnings in 2026
Tornado Warning 20, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at May 31, 2026, 7:42 PM CDT for McCook County, Minnehaha County, South Dakota. It was in force for 23 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- May 31, 2026, 7:42 PM CDT (00:42 UTC)
- Expired
- May 31, 2026, 8:05 PM CDT
- In force
- 23 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 1.0 in
Counties McCook County, SD, Minnehaha County, SD
The radar
The Sioux Falls radar (KFSD), 31 km from the middle of the area, began a volume at 00:43 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.
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 nearest sounding before it
Aberdeen, SD (KABR), launched 00:00Z, 0.7 hours before the alert went out and 176 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
- 1517 J/kg
- Mixed-layer CIN
- -19 J/kg
- Mixed-layer LCL
- 1020 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 120 m²/s²
- 0-3 km storm-relative helicity
- 168 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
635
WFUS53 KFSD 010042
TORFSD
SDC087-099-010130-
/O.NEW.KFSD.TO.W.0020.260601T0042Z-260601T0130Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
742 PM CDT Sun May 31 2026
The National Weather Service in Sioux Falls has issued a
* Tornado Warning for...
West central Minnehaha County in southeastern South Dakota...
East central McCook County in southeastern South Dakota...
* Until 830 PM CDT.
* At 742 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Lake Vermillion State Recreation Area, moving east
at 15 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 dangerous storm will be near...
Hartford and Humboldt around 750 PM CDT.
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 4357 9720 4365 9722 4372 9696 4359 9695
TIME...MOT...LOC 0042Z 259DEG 12KT 4363 9715
TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
$$
SG1 follow-up statement
611 WWUS53 KFSD 010105 SVSFSD Severe Weather Statement National Weather Service Sioux Falls SD 805 PM CDT Sun May 31 2026 SDC087-099-010115- /O.CAN.KFSD.TO.W.0020.000000T0000Z-260601T0130Z/ Minnehaha SD-McCook SD- 805 PM CDT Sun May 31 2026 ...THE TORNADO WARNING FOR WEST CENTRAL MINNEHAHA AND EAST CENTRAL MCCOOK COUNTIES IS CANCELLED... The storm which prompted the warning has weakened below severe limits, and no longer appears capable of producing a tornado. Therefore, the warning has been cancelled. However, small hail is still possible with this thunderstorm. A Severe Thunderstorm Watch remains in effect until 100 AM CDT for southeastern South Dakota. To report severe weather, contact your nearest law enforcement agency. They will relay your report to the National Weather Service Sioux Falls. Remember, a Tornado Warning still remains in effect for southwestern Minnehaha County until 845 PM CDT. && LAT...LON 4357 9720 4365 9722 4372 9696 4359 9695 TIME...MOT...LOC 0103Z 259DEG 12KT 4364 9704 $$ 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 31, 6:55 PM CDT, 47 minutes earlier. Its key messages:
- Isolated to scattered thunderstorms should develop late this afternoon into early evening. Large hail up to half dollar and damaging winds to 60 mph would be the main hazards. A Level 1 of 5 risk for severe storms covers most of the area for this threat.
- Similar to today, a conditional Level 1 of 5 risk for severe storms covers the forecast area Monday afternoon. The chance of development looks lower than today, but if a storm can form, large hail and isolated damaging winds could occur.
- High chances (50-80%) for rain will persist through the bulk of next week. However, severe storm chances continue to look low (near 5% or less) through next week. The better chances for rainfall appear to be Wednesday in central SD and Wednesday night into Thursday area wide.
Area forecast discussion, May 31, 6:55 PM CDT, 47 minutes before
Area Forecast Discussion National Weather Service Sioux Falls SD Issued by National Weather Service Rapid City SD 655 PM CDT Sun May 31 2026 .KEY MESSAGES... - Isolated to scattered thunderstorms should develop late this afternoon into early evening. Large hail up to half dollar and damaging winds to 60 mph would be the main hazards. A Level 1 of 5 risk for severe storms covers most of the area for this threat. - Similar to today, a conditional Level 1 of 5 risk for severe storms covers the forecast area Monday afternoon. The chance of development looks lower than today, but if a storm can form, large hail and isolated damaging winds could occur. - High chances (50-80%) for rain will persist through the bulk of next week. However, severe storm chances continue to look low (near 5% or less) through next week. The better chances for rainfall appear to be Wednesday in central SD and Wednesday night into Thursday area wide. && .DISCUSSION... Issued at 1235 PM CDT Sun May 31 2026 An active pattern is expected over the next several days, although severe weather appears to remain a minor threat. Patchy heavy rain may play the bigger role with each event. For this afternoon and tonight, a small corridor of low level convergence and lift will focus near and just east of the James Valley. Clouds have cleared through early afternoon and temperatures have risen a touch. Along with this temperature rise is a turn in the surface winds to a more south to southwest direction vs. southeast. This is what is aiding in this low level convergence. The latest model soundings indicate something around 1500-2000 J/kg CAPE but weak, disorganized shear. This suggests severe weather should remain limited, but maybe a cell merger or two could produce a couple of updrafts strong enough to support hail to half dollar and wind gusts to 60 mph. Stronger storms will likely drift east or northeast at about 15 mph, so fairly slow moving. With this slower storm motion in mind, will need to keep an eye on the locally heavy rain potential. A handful of the latest hi-res models are showing small areas of 1-3" of rain with this development. One area to keep a closer eye on will be parts of Western Lake county, Northeast McCook and western Minnehaha where 1-3" of rain fell late last night. The question becomes what will drive development; will it be diurnal heating, which would allow updrafts to start developing around 19- 21z, or will it be the weak wave which moves into the area closer to 0-3z this evening. The latest HRRR and Nam output agree with the later start times, with the Nam indicating a stronger cap and less development, while the RRFS and RAP kick off development a little sooner with weaker capping. With the clearing that we are seeing in central SD towards the James Valley we may see some development by mid to late afternoon as destabilization is more likely. Suspect some development between about 5-6pm. One last thing to watch out for, if we can get mid to late afternoon development, the LFC are marginally low and a weak convergent boundary should be in parts of south central and southeast SD, so an isolated funnel or two will be possible. While a marginal risk for severe weather is in place for Monday, confidence in the chances of development are very low. A capping inversion may win out and for now CAPE values only running around 1000 J/kg with continued weak shear, albeit a little bit better than today. Another wave moves through Tuesday but weak shear and weak instability suggest if anything can develop severe weather is very unlikely. Wednesday into Thursday looks like the better chance for more clouds and better rainfall chances. Broad southerly warm advection looks to bring in some weak elevated instability as low pressure tracks east through ND. For now not anticipating all day rainfall but should see off and on chances Wednesday and Thursday as this low tracks by to the north. Friday into Sunday will see periodic weaker waves move through the area with a continuation of relatively weak flow aloft. This continued weaker shear environment should keep severe weather threats very limited. && .AVIATION...(For the 00Z TAFS Through 00Z Monday Evening) Issued At 651 PM CDT Sun May 31 2026 Isolated showers and thunderstorms will continue to be possible across the area through the early evening hours. Low stratus is expected to develop tonight over southwest Minnesota and eastern South Dakota, especially near and east of I-29. Highest confidence location for this MVFR to IFR stratus regarding the TAF sites will be at KFSD. Winds will turn light through the overnight hours, and this could also result in fog, though confidence is a bit lower in development. Additional showers and storms may develop Monday afternoon, but low confidence in development and location of these storms preclude mention in the TAFs at this time. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && DISCUSSION...08 AVIATION...13
Hazardous weather outlook, May 31, 1:33 PM CDT, 6 hours 9 minutes before
Hazardous Weather Outlook National Weather Service Sioux Falls SD 133 PM CDT Sun May 31 2026 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-NEZ013-014-SDZ038>040-050-052>071-011845- 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- 133 PM CDT Sun May 31 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 Level 1 of 5 risk for severe storms is in place for late this afternoon and evening. Isolated to scattered thunderstorms should develop late this afternoon between the James River and I-29, then progress eastward through the evening. A very isolated stronger storm could produce hail to half dollar and wind gusts to 60 mph. Locally heavier rain will also be possible with small swaths of one to three inches of rainfall. .DAYS TWO THROUGH SEVEN...Monday through Saturday. There is a low chance for storms again Monday afternoon. Similar to today, confidence in storm development is low. However, if storms can develop, isolated damaging winds and large hail would be the main threats. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
In the hours before
Local storm report, May 31, 5:45 PM CDT, 1 hour 57 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
545 PM CDT Sun May 31 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0530 PM Hail 1 WSW Emery 43.60N 97.63W
05/31/2026 E1.00 Inch Hanson SD Trained Spotter
Very heavy rain along with penny to quarter
sized hail. Rainfall is already over 3
inches.
&&
TRMLocal storm report, May 31, 6:09 PM CDT, 1 hour 33 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
609 PM CDT Sun May 31 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0600 PM Funnel Cloud 1 N Bridgewater 43.57N 97.50W
05/31/2026 McCook SD Trained Spotter
&&
TRMLocal storm report, May 31, 6:13 PM CDT, 1 hour 29 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
613 PM CDT Sun May 31 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0607 PM Tornado 1 NW Bridgewater 43.56N 97.52W
05/31/2026 McCook SD Storm Chaser
Tornado is kicking up dust from the ground
now.
&&
TRMLocal storm report, May 31, 7:24 PM CDT, 18 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
724 PM CDT Sun May 31 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0723 PM Rain Emery 43.60N 97.62W
05/31/2026 M3.50 Inch Hanson SD Law Enforcement
&&
PRLocal storm report, May 31, 7:38 PM CDT, 4 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
738 PM CDT Sun May 31 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0726 PM Hail 2 WSW Humboldt 43.63N 97.12W
05/31/2026 M1.00 Inch Minnehaha SD Trained Spotter
In addition to hail up to the size of
quarters, heavy rainfall was reported.
&&
TRMLocal storm report, May 31, 7:40 PM CDT, 2 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
740 PM CDT Sun May 31 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0733 PM Hail 4 SW Hurley 43.24N 97.15W
05/31/2026 E1.00 Inch Turner SD Fire Dept/Rescue
&&
TRMThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 31, 7:06 PM CDT | Tornado Warning | FSD | McCook, Minnehaha | 39 min |
| May 31, 7:08 PM CDT | Severe Thunderstorm Warning | FSD | McCook, Minnehaha | 52 min |
| May 31, 7:23 PM CDT | Severe Thunderstorm Warning | FSD | Lincoln, Turner | 52 min |
| May 31, 7:50 PM CDT | Tornado Warning | FSD | Turner | 40 min |
| May 31, 7:54 PM CDT | Severe Thunderstorm Warning | FSD | Minnehaha | 51 min |
| May 31, 8:03 PM CDT | Tornado Warning | FSD | Minnehaha | 42 min |
| May 31, 8:21 PM CDT | Severe Thunderstorm Warning | FSD | Lincoln, Turner | 54 min |
| May 31, 8:29 PM CDT | Tornado Warning | FSD | Lincoln, Turner | 46 min |
| May 31, 8:42 PM CDT | Severe Thunderstorm Warning | FSD | Clay, Lincoln, Turner, Yankton | 63 min |
| May 31, 8:43 PM CDT | Tornado Warning | FSD | Minnehaha | 32 min |
| May 31, 8:57 PM CDT | Tornado Warning | FSD | Lincoln, Turner | 35 min |
| May 31, 9:11 PM CDT | Tornado Warning | FSD | Clay, Union | 49 min |
| May 31, 9:43 PM CDT | Severe Thunderstorm Warning | FSD | Clay, Union | 47 min |
| May 31, 11:08 PM CDT | Severe Thunderstorm Warning | FSD | Union | 52 min |
Nearby
Tornado Warnings in South Dakota, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.