Alert archive / Iowa / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 16, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Apr 13, 2026, 7:36 PM CDT for Clay County, Iowa. It was in force for 36 min. 3 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
- Apr 13, 2026, 7:36 PM CDT (00:36 UTC)
- Expired
- Apr 13, 2026, 8:12 PM CDT
- In force
- 36 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Hail
- 1.25 in
- Wind
- 60.0 mph
County Clay County, IA
The radar
The Sioux Falls radar (KFSD), 148 km from the middle of the area, began a volume at 00:40 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 |
|---|---|---|---|
| Apr 13, 7:49 PM CDT | TORNADO | 2 Nne Webb, IA | Photo of tornado from EM. |
| Apr 13, 7:50 PM CDT | TSTM WND DMG | 1 Ne Webb, IA | Measured wind gust to 72 mph on a personal weather station due to rear flank downdraft to south of tornado path. Damage to trees, shingles and siding. Some wind driven hail knocked out windows on camper and damaged siding. |
| Apr 13, 7:52 PM CDT | HAIL 1 | Webb, IA |
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 3 storm reports to this severe thunderstorm warning; the first came 14 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 |
|---|---|---|---|
| Apr 13, 4:39 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 0.6 hours before the alert went out and 220 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
- 215 J/kg
- Mixed-layer CIN
- -51 J/kg
- Mixed-layer LCL
- 3086 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 152 m²/s²
- 0-3 km storm-relative helicity
- 239 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.0
The text
As transmitted.
574
WUUS53 KFSD 140036
SVRFSD
IAC041-140130-
/O.NEW.KFSD.SV.W.0016.260414T0036Z-260414T0130Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
736 PM CDT Mon Apr 13 2026
The National Weather Service in Sioux Falls has issued a
* Severe Thunderstorm Warning for...
Clay County in northwestern Iowa...
* Until 830 PM CDT.
* At 736 PM CDT, a severe thunderstorm was located near Greenville,
or 12 miles south of Spencer In Clay County, moving northeast at 35
mph.
HAZARD...60 mph wind gusts and half dollar size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.
* This severe thunderstorm will be near...
Spencer In Clay County, Webb, and Greenville around 740 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Sioux Falls.
&&
LAT...LON 4291 9502 4291 9534 4325 9517 4325 9491
4302 9492
TIME...MOT...LOC 0036Z 210DEG 31KT 4297 9515
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
IG2 follow-up statements
431
WWUS53 KFSD 140048
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
748 PM CDT Mon Apr 13 2026
IAC041-140130-
/O.CON.KFSD.SV.W.0016.000000T0000Z-260414T0130Z/
Clay IA-
748 PM CDT Mon Apr 13 2026
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM CDT
FOR SOUTHEASTERN CLAY COUNTY...
At 748 PM CDT, a severe thunderstorm was located near Sioux Rapids,
or 14 miles south of Spencer In Clay County, moving northeast at 15
mph.
HAZARD...60 mph wind gusts and half dollar size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage to
roofs, siding, and trees.
This severe storm will be near...
Webb around 755 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Sioux Falls.
&&
LAT...LON 4291 9502 4291 9519 4311 9514 4312 9492
4302 9492
TIME...MOT...LOC 0048Z 244DEG 13KT 4293 9511
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
IG351
WWUS53 KFSD 140112
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
812 PM CDT Mon Apr 13 2026
IAC041-140122-
/O.CAN.KFSD.SV.W.0016.000000T0000Z-260414T0130Z/
Clay IA-
812 PM CDT Mon Apr 13 2026
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CLAY COUNTY IS
CANCELLED...
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.
A Severe Thunderstorm 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 9502 4291 9519 4311 9514 4312 9492
4302 9492
TIME...MOT...LOC 0111Z 210DEG 31KT 4311 9497
$$
IGWhat forecasters said that day
The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Apr 13, 6:41 PM CDT, 55 minutes earlier. Its key messages:
- Thunderstorms return this afternoon and evening. Scattered strong to severe storms expected - greatest risk for southwestern Minnesota into adjacent areas of South Dakota and northwest Iowa. Timing of greatest concern is 4 to 9 PM.
- Main hazards are large hail greater than 2 inches in diameter and wind gusts to 70 mph. A tornado or two are also possible. Have a severe weather plan and multiple ways to receive warnings.
- Periodic chances (20-60%) for showers and thunderstorms continue this week. Details remain uncertain at this time.
Area forecast discussion, Apr 13, 6:41 PM CDT, 55 minutes before
Area Forecast Discussion National Weather Service Sioux Falls SD 641 PM CDT Mon Apr 13 2026 .KEY MESSAGES... - Thunderstorms return this afternoon and evening. Scattered strong to severe storms expected - greatest risk for southwestern Minnesota into adjacent areas of South Dakota and northwest Iowa. Timing of greatest concern is 4 to 9 PM. - Main hazards are large hail greater than 2 inches in diameter and wind gusts to 70 mph. A tornado or two are also possible. Have a severe weather plan and multiple ways to receive warnings. - Periodic chances (20-60%) for showers and thunderstorms continue this week. Details remain uncertain at this time. && .DISCUSSION... Issued at 238 PM CDT Mon Apr 13 2026 Scattered thunderstorms are set to develop over the next few hours, bringing the potential for a few severe storms with large hail, damaging winds, and perhaps a tornado or two. As of 2 pm, a surface low is located over northern Nebraska with a warm front extending northeast of it across far southeastern South Dakota into northwest Iowa. Dew points in the 60s have been gradually spreading northward, and these higher dew points are expected to reach the I-90 corridor over the next couple of hours. This boundary will be the focus of initial storm development, with these storms having access to 35-50 kts of effective bulk shear and 1500-2000 J/kg of MLCAPE. There are questions though on how much some high clouds have limited the area from reaching full heating potential, but if a storm can get going then steep mid level lapse rates of 7.5-8.5 degrees C/km and mostly straight, elongated hodographs will favor large hail to around 2 inches in diameter or larger. The secondary threat will be damaging wind gusts up to 70 mph. If a storm can get rooted to the aforementioned surface warm front, then a tornado or two will also be possible. Can't rule out a strong tornado either, primarily over southwest Minnesota. As the low pressure system drift across the area, a few additional showers and storms look to develop farther south across northwest Iowa (down to about IA Highway-3, or just north of US Highway-20) within the warm sector around sunset. These storms could also be on the strong to severe side, with an isolated instance of quarter sized hail and 60 mph as the threats. Showers and storms will exit off to our east by the mid evening hours, leaving mostly quiet conditions in its wake. A few showers may develop in central South Dakota prior to daybreak Tuesday, but dry air should win out and prevent most if not all of this from reaching the ground. Patchy fog will also be possible by early Tuesday morning across portions of northwest Iowa and southwest Minnesota as winds turn light and variable overnight and ample moisture remains in place. Temperatures tonight drop mainly in the 40s, though some 50s are possible in our easternmost areas. Low chances for showers continue into the day on Tuesday, but activity is expected to remain spotty at best as rain continues to battle a dry sub cloud layer. Highs will range from the 60s northwest to 70s southeast. Rain chances look to increase Tuesday night into Wednesday as two shortwave troughs impact our area. The best chances of rain and storms look to be over northwest Iowa and adjacent areas of Nebraska, South Dakota, and Minnesota. At this time, severe weather looks unlikely with this system as the better instability looks to be off to our south and east. Rain and storms exit off to our east by Wednesday night, leading to a dry Thursday. Winds look to increase on Thursday especially west of I-29 closer to a deepening surface low, and winds may take on a southwesterly component especially in south central South Dakota. This could lead to another day with higher fire danger as temperatures will be warm and relative humidity values drop to 25% or below mainly along and west of the James River. Still some uncertainty into how breezy the winds will be, so keep up to date with the latest forecast. Not too much time to look into the extended forecast given the near term severe weather threat, but guidance is in fairly good agreement that the western trough will begin to move into our area by the end of the work week/early weekend. This could bring more rain and storms to our area on Friday and then colder weather into Saturday as guidance indicates a stronger push of cold air advection behind this system. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 641 PM CDT Mon Apr 13 2026 VFR conditions are expected for the majority of the period. Thunderstorms, some severe producing 2+ inch hail, are ongoing east of I-29 in northwest Iowa and southwest Minnesota. These storms will continue to track northeast through about 14.03Z. Some patchy dense fog is possible near daybreak east of I-29. This should burn off by mid morning. A few light rain showers are possible again Wednesday afternoon but confidence is too low to include in the TAFs at this time. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && DISCUSSION...Samet AVIATION...AJP
Hazardous weather outlook, Apr 13, 3:56 PM CDT, 3 hours 40 minutes before
Hazardous Weather Outlook National Weather Service Sioux Falls SD 356 PM CDT Mon Apr 13 2026 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-NEZ013-014-SDZ038>040-050-052>071-142100- 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- 356 PM CDT Mon Apr 13 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. Scattered strong to severe thunderstorms expected Monday afternoon and evening. Some storms may produce large hail 2 inches in diameter and damaging wind gusts up to 70 mph. A tornado or two cannot be ruled out. Greatest risk of storms is north of I-90 between 4 and 10 PM. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. More widespread chances for showers and thunderstorms exists for Tuesday afternoon into Wednesday. This more active pattern continues into the weekend. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
In the hours before
Local storm report, Apr 13, 6:56 PM CDT, 40 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
656 PM CDT Mon Apr 13 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0625 PM Hail 7 ENE Melvin 43.32N 95.48W
04/13/2026 E1.00 Inch Osceola IA Trained Spotter
Spotter report of quarter inch hail with
pictures.
&&
AJPLocal storm report, Apr 13, 6:57 PM CDT, 39 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
657 PM CDT Mon Apr 13 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0650 PM Hail Windom 43.87N 95.12W
04/13/2026 E1.25 Inch Cottonwood MN Trained Spotter
&&
TRMLocal storm report, Apr 13, 7:23 PM CDT, 13 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
723 PM CDT Mon Apr 13 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0720 PM Hail 4 ESE Arnolds Park 43.35N 95.05W
04/13/2026 M0.75 Inch Dickinson IA Trained Spotter
&&
JCLocal storm report, Apr 13, 7:24 PM CDT, 12 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
724 PM CDT Mon Apr 13 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0620 PM Hail 2 NW Windom 43.89N 95.16W
04/13/2026 M2.00 Inch Cottonwood MN Public
Social media report with pictures and ruler.
&&
AJPLocal storm report, Apr 13, 7:25 PM CDT, 11 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
725 PM CDT Mon Apr 13 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0713 PM Hail 4 NE Magnolia 43.68N 96.01W
04/13/2026 E0.75 Inch Nobles MN Trained Spotter
&&
TRMLocal storm report, Apr 13, 7:33 PM CDT, 3 minutes before
Preliminary Local Storm Report
National Weather Service Sioux Falls SD
733 PM CDT Mon Apr 13 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0630 PM Hail 8 SE Ocheyedan 43.33N 95.45W
04/13/2026 E1.00 Inch Osceola IA Public
Social media report with a coin for
reference. Time estimated by radar.
&&
AJPThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 13, 7:43 PM CDT | Tornado Warning | FSD | Buena Vista, Clay | 32 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 2026Every severe thunderstorm warning 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.