Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 83, NWS Sioux Falls, SD

August 6, 2021Lyon County, Sioux County, Iowa; Lincoln County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 6, 2021, 1:06 AM CDT for Lyon County, Sioux County, Iowa; Lincoln County, South Dakota. It was in force for 39 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 6, 2021, 1:06 AM CDT (06:06 UTC)
Expired: Aug 6, 2021, 1:45 AM CDT
In force: 39 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.5 in
Wind: 50.0 mph

Counties Lyon County, IA, Sioux County, IA, Lincoln County, SD

The radar

The Sioux Falls radar (KFSD), 51 km from the middle of the area, began a volume at 06:09 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
Aug 6, 1:06 AM CDT	HAIL 1	1 Sw Canton, SD	REPORT VIA SOCIAL MEDIA. TIME ESTIMATED VIA RADAR.

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

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 6.1 hours before the alert went out and 245 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 835 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 1549 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 259 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

517 
WUUS53 KFSD 060606
SVRFSD
IAC119-167-SDC083-060645-
/O.NEW.KFSD.SV.W.0083.210806T0606Z-210806T0645Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
106 AM CDT Fri Aug 6 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Southwestern Lyon County in northwestern Iowa...
  Northwestern Sioux County in northwestern Iowa...
  Southeastern Lincoln County in southeastern South Dakota...

* Until 145 AM CDT.

* At 106 AM CDT, a severe thunderstorm was located just west of 
  Canton, moving southeast at 25 mph.

  HAZARD...Ping pong ball size hail.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect 
           damage to roofs, siding, windows, and vehicles.

* This severe thunderstorm will be near...
  Newton Hills State Park around 115 AM CDT.
  Fairview around 125 AM CDT.
  Hudson around 140 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows!

&&

LAT...LON 4330 9673 4332 9653 4308 9634 4308 9645
      4309 9649 4308 9650 4309 9650 4308 9652
      4308 9668
TIME...MOT...LOC 0606Z 330DEG 20KT 4328 9662 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Chapman

2 follow-up statements

399 
WWUS53 KFSD 060618
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
118 AM CDT Fri Aug 6 2021

IAC119-167-SDC083-060645-
/O.CON.KFSD.SV.W.0083.000000T0000Z-210806T0645Z/
Lyon IA-Sioux IA-Lincoln SD-
118 AM CDT Fri Aug 6 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 AM CDT
FOR SOUTHWESTERN LYON...NORTHWESTERN SIOUX AND SOUTHEASTERN LINCOLN
COUNTIES...

At 118 AM CDT, a severe thunderstorm was located over Newton Hills
State Park, or near Canton, moving southeast at 25 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

This severe storm will be near...
  Fairview around 125 AM CDT.
  Hudson around 140 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

LAT...LON 4325 9666 4330 9651 4308 9634 4308 9645
      4309 9649 4308 9650 4309 9650 4308 9652
      4308 9662
TIME...MOT...LOC 0618Z 330DEG 20KT 4322 9657 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Chapman

292 
WWUS53 KFSD 060630
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
130 AM CDT Fri Aug 6 2021

IAC119-060640-
/O.CAN.KFSD.SV.W.0083.000000T0000Z-210806T0645Z/
Lyon IA-
130 AM CDT Fri Aug 6 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN LYON COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4316 9654 4322 9645 4308 9634 4308 9645
      4309 9649 4308 9650 4309 9650 4308 9652
      4308 9657
TIME...MOT...LOC 0630Z 326DEG 24KT 4313 9648 

$$

IAC167-SDC083-060645-
/O.CON.KFSD.SV.W.0083.000000T0000Z-210806T0645Z/
Sioux IA-Lincoln SD-
130 AM CDT Fri Aug 6 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 AM CDT
FOR NORTHWESTERN SIOUX AND SOUTHEASTERN LINCOLN COUNTIES...

At 130 AM CDT, a severe thunderstorm was located over Hudson, or 9
miles north of Hawarden, moving southeast at 30 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

This severe thunderstorm will remain over mainly rural areas of
northwestern Sioux and southeastern Lincoln Counties near Hudson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

LAT...LON 4316 9654 4322 9645 4308 9634 4308 9645
      4309 9649 4308 9650 4309 9650 4308 9652
      4308 9657
TIME...MOT...LOC 0630Z 326DEG 24KT 4313 9648 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Chapman

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 5, 8:57 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Lyon	48 min
Aug 5, 9:31 PM CDT	Severe Thunderstorm Warning	FSD	Lyon, Sioux	44 min
Aug 5, 10:04 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	41 min
Aug 6, 12:10 AM CDT	Severe Thunderstorm Warning	FSD	Woodbury	35 min
Aug 6, 1:36 AM CDT	Severe Thunderstorm Warning	FSD	Sioux	24 min
Aug 5, 7:00 PM CDT	Severe Thunderstorm Warning	FSD	Lake, Moody	45 min
Aug 5, 7:28 PM CDT	Severe Thunderstorm Warning	FSD	Brookings, Moody	32 min
Aug 5, 7:44 PM CDT	Severe Thunderstorm Warning	FSD	Moody	33 min
Aug 5, 7:58 PM CDT	Severe Thunderstorm Warning	FSD	Lake, Minnehaha, Moody	47 min
Aug 5, 8:24 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Minnehaha, Moody	51 min
Aug 5, 9:04 PM CDT	Severe Thunderstorm Warning	FSD	Minnehaha	28 min
Aug 5, 10:36 PM CDT	Severe Thunderstorm Warning	FSD	Clay, Lincoln, Turner, Union	39 min
Aug 5, 11:40 PM CDT	Severe Thunderstorm Warning	FSD	Minnehaha	50 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021 Severe Thunderstorm Warnings in South Dakota, 2021 Every 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.