Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 101, NWS Sioux Falls, SD

August 24, 2021Lyon County, Osceola County, Iowa; Nobles County, Minnesota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 24, 2021, 9:43 AM CDT for Lyon County, Osceola County, Iowa; Nobles County, Minnesota. It was in force for 47 min. 1 report 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
Aug 24, 2021, 9:43 AM CDT (14:43 UTC)
Expired
Aug 24, 2021, 10:30 AM CDT
In force
47 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Lyon County, IA, Osceola County, IA, Nobles County, MN

The radar

The Sioux Falls radar (KFSD), 64 km from the middle of the area, began a volume at 14:43 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.

What was reported inside it

TimeReportWhereRemark
Aug 24, 10:25 AM CDTHAIL 1Little Rock, IARECEIVED QUARTER SIZED HAIL, BUT SAID THAT THE ACCUMULATION WAS NOT DEEP.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 2.7 hours before the alert went out and 237 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, Omaha, NE at 12:00Z on 2021-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 989 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2021-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 103 square meters per square second.193958Sfc1 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
989 J/kg
Mixed-layer CIN
-401 J/kg
Mixed-layer LCL
1868 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
103 m²/s²
0-3 km storm-relative helicity
129 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

742 
WUUS53 KFSD 241443
SVRFSD
IAC119-143-MNC105-241530-
/O.NEW.KFSD.SV.W.0101.210824T1443Z-210824T1530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
943 AM CDT Tue Aug 24 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Northeastern Lyon County in northwestern Iowa...
  Northwestern Osceola County in northwestern Iowa...
  South central Nobles County in southwestern Minnesota...

* Until 1030 AM CDT.

* At 943 AM CDT, a severe thunderstorm was located near George, or
  near Rock Rapids, moving east at 25 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Little Rock and Sibley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4333 9610 4338 9620 4346 9615 4362 9573
      4345 9555
TIME...MOT...LOC 1443Z 251DEG 24KT 4342 9605 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

BP
2 follow-up statements
316 
WWUS53 KFSD 241506
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
1006 AM CDT Tue Aug 24 2021

IAC119-143-MNC105-241530-
/O.CON.KFSD.SV.W.0101.000000T0000Z-210824T1530Z/
Lyon IA-Osceola IA-Nobles MN-
1006 AM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 AM CDT
FOR NORTHEASTERN LYON...NORTHWESTERN OSCEOLA AND SOUTH CENTRAL NOBLES
COUNTIES...

At 1005 AM CDT, a severe thunderstorm was located near Ellsworth, or
11 miles northeast of Rock Rapids, moving east at 40 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
  Little Rock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4339 9583 4347 9612 4362 9573 4345 9555
TIME...MOT...LOC 1505Z 255DEG 34KT 4350 9596 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

BP
229 
WWUS53 KFSD 241527
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
1027 AM CDT Tue Aug 24 2021

IAC119-143-MNC105-241537-
/O.EXP.KFSD.SV.W.0101.000000T0000Z-210824T1530Z/
Lyon IA-Osceola IA-Nobles MN-
1027 AM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN LYON...
NORTHWESTERN OSCEOLA AND SOUTH CENTRAL NOBLES COUNTIES WILL EXPIRE AT
1030 AM CDT...
        
The storm which prompted the warning has moved out of the area.
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 4339 9583 4347 9612 4362 9573 4345 9555
TIME...MOT...LOC 1527Z 251DEG 24KT 4354 9578 

$$

BP

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 24, 3:31 AM CDTHeat AdvisoryFSDPlymouth, Woodbury11 hr
Aug 24, 10:44 AM CDTSevere Thunderstorm WarningFSDDickinson, Osceola30 min
Aug 24, 8:16 AM CDTSevere Thunderstorm WarningFSDCottonwood, Murray44 min
Aug 24, 8:59 AM CDTSevere Thunderstorm WarningFSDCottonwood, Murray61 min
Aug 24, 10:00 AM CDTSevere Thunderstorm WarningFSDCottonwood, Jackson, Nobles, Rock45 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Severe Thunderstorm Warnings in Minnesota, 2021Every severe thunderstorm warning in 2021

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.