Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 87, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 8, 2021, 4:50 PM CDT for 4 counties in Iowa. It was in force for 55 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 8, 2021, 4:50 PM CDT (21:50 UTC)
- Expired
- Aug 8, 2021, 5:45 PM CDT
- In force
- 55 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Tornado
- Possible
- Damage threat
- Considerable
- Hail
- 1.75 in
- Wind
- 60.0 mph
Counties Clay County, IA, Dickinson County, IA, O'Brien County, IA, Osceola County, IA
The radar
The Sioux Falls radar (KFSD), 111 km from the middle of the area, began a volume at 21:49 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 8, 4:52 PM CDT | TORNADO | 2 Sse Ocheyedan, IA | DAMAGE TO THE ROOF OF A CHICKEN BARN. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Minneapolis, MN (KMPX), launched 12:00Z, 9.8 hours before the alert went out and 226 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
- 1659 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 542 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 11 m²/s²
- 0-3 km storm-relative helicity
- 24 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.9
The text
As transmitted.
724
WUUS53 KFSD 082150
SVRFSD
IAC041-059-141-143-082245-
/O.NEW.KFSD.SV.W.0087.210808T2150Z-210808T2245Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
450 PM CDT Sun Aug 8 2021
The National Weather Service in Sioux Falls has issued a
* Severe Thunderstorm Warning for...
Southeastern Osceola County in northwestern Iowa...
Southwestern Dickinson County in northwestern Iowa...
Northwestern Clay County in northwestern Iowa...
Northeastern O'Brien County in northwestern Iowa...
* Until 545 PM CDT.
* At 449 PM CDT, a severe thunderstorm was located near Ocheyedan, or
14 miles east of Sibley, moving southeast at 20 mph.
HAZARD...Golf 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.
* Locations impacted include...
Hartley and Everly.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
This thunderstorm is capable of producing all types of severe weather
including extremely large hail, destructive straight line winds and
tornadoes. Move quickly to a safe shelter such as an interior room, a
bathroom, closet or basement.
&&
LAT...LON 4339 9558 4345 9539 4316 9508 4309 9546
TIME...MOT...LOC 2149Z 330DEG 18KT 4337 9546
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Kalin1 follow-up statement
635
WWUS53 KFSD 082224
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
524 PM CDT Sun Aug 8 2021
IAC041-059-141-143-082245-
/O.CON.KFSD.SV.W.0087.000000T0000Z-210808T2245Z/
Osceola IA-Dickinson IA-Clay IA-O'Brien IA-
524 PM CDT Sun Aug 8 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM CDT
FOR SOUTHEASTERN OSCEOLA...SOUTHWESTERN DICKINSON...NORTHWESTERN CLAY
AND NORTHEASTERN O'BRIEN COUNTIES...
At 524 PM CDT, a severe thunderstorm was located near Everly, or 12
miles northwest of Spencer In Clay County, moving southeast at 30
mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage to
roofs, siding, and trees.
Locations impacted include...
Spencer In Clay County, Hartley, Everly and Moneta.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
This thunderstorm is capable of producing all types of severe weather
including extremely large hail, destructive straight line winds and
tornadoes. Move quickly to a safe shelter, such as an interior room,
a bathroom or closet or basement.
&&
LAT...LON 4334 9556 4336 9529 4316 9508 4309 9546
TIME...MOT...LOC 2224Z 327DEG 24KT 4325 9535
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
SGThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 4:10 PM CDT | Severe Thunderstorm Warning | FSD | Osceola | 50 min |
| Aug 8, 4:29 PM CDT | Tornado Warning | FSD | Osceola | 31 min |
| Aug 8, 5:26 PM CDT | Tornado Warning | FSD | Clay, Dickinson, O'Brien | 49 min |
| Aug 8, 6:31 PM CDT | Tornado Warning | FSD | Buena Vista, Clay | 44 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.