Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 78, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 5, 2021, 9:31 PM CDT for Lyon County, Sioux County, Iowa. It was in force for 44 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
- Aug 5, 2021, 9:31 PM CDT (02:31 UTC)
- Expired
- Aug 5, 2021, 10:15 PM CDT
- In force
- 44 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Hail
- 1.5 in
- Wind
- 60.0 mph
Counties Lyon County, IA, Sioux County, IA
The radar
The Sioux Falls radar (KFSD), 51 km from the middle of the area, began a volume at 02:33 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.
The nearest sounding before it
Aberdeen, SD (KABR), launched 00:00Z, 2.5 hours before the alert went out and 248 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
- 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
The text
As transmitted.
637
WUUS53 KFSD 060231
SVRFSD
IAC119-167-060315-
/O.NEW.KFSD.SV.W.0078.210806T0231Z-210806T0315Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
931 PM CDT Thu Aug 5 2021
The National Weather Service in Sioux Falls has issued a
* Severe Thunderstorm Warning for...
Southwestern Lyon County in northwestern Iowa...
Northern Sioux County in northwestern Iowa...
* Until 1015 PM CDT.
* At 930 PM CDT, a severe thunderstorm was located near Larchwood, or
9 miles northeast of Canton, moving southeast at 35 mph.
HAZARD...Ping pong ball size hail and 60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect
wind damage to roofs, siding, and trees.
* This severe thunderstorm will be near...
Inwood around 940 PM CDT.
Alvord around 945 PM CDT.
Other locations in the path of this severe thunderstorm include Doon,
Rock Valley and Hull.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.
&&
LAT...LON 4305 9649 4307 9646 4310 9646 4312 9644
4316 9647 4322 9647 4323 9649 4341 9650
4345 9636 4321 9592
TIME...MOT...LOC 0230Z 323DEG 29KT 4340 9643
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
SSC2 follow-up statements
174
WWUS53 KFSD 060249
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
949 PM CDT Thu Aug 5 2021
IAC119-167-060315-
/O.CON.KFSD.SV.W.0078.000000T0000Z-210806T0315Z/
Lyon IA-Sioux IA-
949 PM CDT Thu Aug 5 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT
FOR SOUTH CENTRAL LYON AND NORTHEASTERN SIOUX COUNTIES...
At 949 PM CDT, a severe thunderstorm was located near Doon, or 12
miles southwest of Rock Rapids, moving southeast at 35 mph.
HAZARD...60 mph wind gusts and half dollar size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage to
roofs, siding, and trees.
Locations impacted include...
Rock Valley and Hull.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
&&
LAT...LON 4308 9639 4331 9641 4338 9624 4321 9592
TIME...MOT...LOC 0249Z 323DEG 29KT 4327 9630
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
SSC067
WWUS53 KFSD 060305
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
1005 PM CDT Thu Aug 5 2021
IAC119-167-060315-
/O.EXP.KFSD.SV.W.0078.000000T0000Z-210806T0315Z/
Lyon IA-Sioux IA-
1005 PM CDT Thu Aug 5 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL LYON AND
NORTHEASTERN SIOUX COUNTIES 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. However small
hail, gusty winds and heavy rain are still possible with this
thunderstorm.
LAT...LON 4308 9639 4331 9641 4338 9624 4321 9592
TIME...MOT...LOC 0305Z 323DEG 29KT 4317 9620
$$
SSCThe 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 | FSD | Lyon | 48 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, 1:06 AM CDT | Severe Thunderstorm Warning | FSD | Lyon, Sioux | 39 min |
| Aug 6, 1:36 AM CDT | Severe Thunderstorm Warning | FSD | Sioux | 24 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.