Alert archive / Iowa / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 124, NWS Sioux Falls, SD

June 23, 2026Osceola County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jun 23, 2026, 9:38 PM CDT for Osceola County, Iowa. It was in force for 37 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
Jun 23, 2026, 9:38 PM CDT (02:38 UTC)
Expired
Jun 23, 2026, 10:15 PM CDT
In force
37 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

County Osceola County, IA

The radar

The Sioux Falls radar (KFSD), 101 km from the middle of the area, began a volume at 02:41 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 severe thunderstorm 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

Minneapolis, MN (KMPX), launched 00:00Z, 2.6 hours before the alert went out and 223 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-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2026-06-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 77 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2026-06-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
77 J/kg
Mixed-layer CIN
-107 J/kg
Mixed-layer LCL
801 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.8

Open this sounding in Storm Lab

The text

As transmitted.

904 
WUUS53 KFSD 240238
SVRFSD
IAC143-240315-
/O.NEW.KFSD.SV.W.0124.260624T0238Z-260624T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
938 PM CDT Tue Jun 23 2026

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Eastern Osceola County in northwestern Iowa...

* Until 1015 PM CDT.

* At 938 PM CDT, a severe thunderstorm was located near Ocheyedan, or
  near Sibley, moving southeast at 30 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* This severe thunderstorm will be near...
  Ocheyedan and Harris around 945 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 4326 9545 4342 9571 4350 9566 4350 9539
      4338 9538
TIME...MOT...LOC 0238Z 295DEG 24KT 4344 9563 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Samet
2 follow-up statements
152 
WWUS53 KFSD 240255
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
955 PM CDT Tue Jun 23 2026

IAC143-240315-
/O.CON.KFSD.SV.W.0124.000000T0000Z-260624T0315Z/
Osceola IA-
955 PM CDT Tue Jun 23 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT
FOR EASTERN OSCEOLA COUNTY...

At 954 PM CDT, a severe thunderstorm was located over Ocheyedan, or
12 miles east of Sibley, moving southeast at 25 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
  Harris.

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 4335 9560 4348 9553 4348 9539 4338 9538
      4326 9545
TIME...MOT...LOC 0254Z 300DEG 23KT 4339 9551 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Samet
003 
WWUS53 KFSD 240307
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
1007 PM CDT Tue Jun 23 2026

IAC143-240317-
/O.EXP.KFSD.SV.W.0124.000000T0000Z-260624T0315Z/
Osceola IA-
1007 PM CDT Tue Jun 23 2026

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN OSCEOLA COUNTY WILL
EXPIRE AT 1015 PM CDT...

The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Sioux Falls.

&&

LAT...LON 4335 9560 4348 9553 4348 9539 4338 9538
      4326 9545
TIME...MOT...LOC 0307Z 295DEG 24KT 4335 9541 

$$

Samet

What 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 Jun 23, 6:50 PM CDT, 2 hours 48 minutes earlier. Its key messages:

  • A cluster of storms continues in southwest Minnesota with isolated showers/storms farther southwest early this evening. The risk for severe weather is decreasing in our forecast area, but stronger storms may produce locally heavier rain, with small hail and a few 40-50 mph gusts also possible.
  • Near to slightly below normal temperatures continue through the end of the week with passing showers and isolated thunderstorms to the north by early Friday.
  • Growing potential for an extended period of heat and humidity beginning Saturday, but intensifying Sunday into next week. Heat and humidity could bring very low probabilities for thunderstorms each day.
Area forecast discussion, Jun 23, 6:50 PM CDT, 2 hours 48 minutes before
Area Forecast Discussion
National Weather Service Sioux Falls SD
650 PM CDT Tue Jun 23 2026

.KEY MESSAGES...

- A cluster of storms continues in southwest Minnesota with
  isolated showers/storms farther southwest early this evening.
  The risk for severe weather is decreasing in our forecast
  area, but stronger storms may produce locally heavier rain,
  with small hail and a few 40-50 mph gusts also possible.

- Near to slightly below normal temperatures continue through
  the end of the week with passing showers and isolated
  thunderstorms to the north by early Friday.

- Growing potential for an extended period of heat and humidity
  beginning Saturday, but intensifying Sunday into next week.
  Heat and humidity could bring very low probabilities for
  thunderstorms each day.

&&

.DISCUSSION...
Issued at 1234 PM CDT Tue Jun 23 2026

THIS AFTERNOON/EVENING:   Weak frontal boundary continues to drift
southeast early this afternoon. Instability continues to slowly grow
ahead of this boundary, through latest RAP/HRRR MLCAPE estimates
continue to range between 900-1400 J/KG. As we reach convective
temps we'll begin to see isolated strong or severe storms by mid-
late afternoon. The increase in effective wind shear AOA 40 knots
could drive a few slightly more organized storms, however rather
marginal mid-lvl lapse rates and tall-thin CAPE profiles may
indicate the severe risks may be more limited.  Analog soundings
would suggest hail up to 1.5" will be possible, with very isolated
stronger wind gusts. The latest SSCRAM guidance also points to
greater hail than wind risks through the heart of the CWA by mid-
late afternoon.  The persistent dPVA this evening along with
flattening of the surface front may keep scattered showers and
embedded thunderstorms going along or south of I-90 through the
evening and into the early overnight hours (along Highway 20). The
severe weather risk should diminish quickly by 7-8PM however.

TONIGHT: A light wind will persist for most of the region overnight,
with a slightly increased northwest wind developing by daybreak
Wednesday.

WEDNESDAY-THURSDAY: A pair of quiet days, with cooler temperatures
can be expected for Wednesday and Thursday as surface ridging moves
through the region. Variable afternoon CU may develop through the
region Wednesday afternoon as highs climb into the middle to upper
70s. Light and variable winds may lead to patchy fog Thursday
morning, though we'll watch for some high level clouds drifting
northward into the MO river valley Thursday morning.  This cloud
cover will be tied to a low-lvl baroclinic zone stretching from the
Black Hills region towards the Omaha area.  Temperatures once again
remain in the middle to  upper 70s.

FRIDAY: A stronger mid-lvl wave ejects out of the Central and
Northern Rockies early Friday. The 00Z ECE/EC continued to be
focused further south than the GEFS/GFS/CMC/CME/NAM with the track
of this wave, associated warm advection, and greatest potential for
light QPF. That said, the probability for more than 0.10" is no more
than 20-30% in any solution.  By Friday afternoon, the advancement
of a warm front and increasing EML should lead to only minor risks
for redevelopment by the evening over central South Dakota.

SATURDAY-MONDAY: A general pattern evolution towards western CONUS
troughing and southeastern CONUS ridging develops quickly Saturday.
This pattern will signal a shift towards much warmer temperatures,
stronger EML development, and convection risks generally driven by
the need for a triggering mechanism to overcome the inhibition. More
impactful will be the arrival of very warm temperatures.
Temperatures Saturday rise toward the middle to upper 80s, however
highs will accelerate upwards Sunday and Monday into the 90s. Latest
NBM/LREF indicate high probabilities (>70) of exceeding 90
degrees with >30-50% probabilities of exceeding 95 degrees
Sunday. One thing to be aware of is the warm bias in GFS and
GEFS surface temperatures as we move through next week which
could skew blends slightly and present some pretty unrealistic
high temperature/CAPE projections.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 642 PM CDT Tue Jun 23 2026

A cluster of storms will continue to move across portions of
southwest Minnesota early this evening, with a low (30-40%)
chance for additional development from northeast Nebraska into
northwest Iowa prior to 24/06Z. Will keep a small window of TS
potential at KSUX this evening, but overall storm chances at TAF
sites are low.

VFR conditions will prevail through the period, though storms
may produce locally IFR conditions and erratic wind gusts to
35-40kt. Away from storms, southwest winds at or below 12kt will
turn to the west and northwest, with occasional gusts 20-25kt
Wednesday afternoon.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

DISCUSSION...Dux
AVIATION...JH
Hazardous weather outlook, Jun 23, 3:01 AM CDT, 18 hours 37 minutes before
Hazardous Weather Outlook
National Weather Service Sioux Falls SD
301 AM CDT Tue Jun 23 2026

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ038>040-050-052>071-240815-
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-
301 AM CDT Tue Jun 23 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...Today and tonight.

Isolated thunderstorms move east this morning; severe weather is not
expected through the morning hours.

Additional thunderstorms may develop this afternoon and into this
evening. An isolated stronger storm may produce half dollar sized
hail and wind gusts to 60 mph between 1 PM and 9 PM CDT today.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Periodic storm chances continue through the work week. At this time,
additional severe weather risks remain low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.