Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 113, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 27, 2021, 1:09 AM CDT for 6 counties in Iowa. It was in force for 51 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 27, 2021, 1:09 AM CDT (06:09 UTC)
- Expired
- Aug 27, 2021, 2:00 AM CDT
- In force
- 51 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Tornado
- Possible
- Damage threat
- Considerable
- Hail
- 0.75 in
- Wind
- 70.0 mph
Counties Cherokee County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sioux County, IA
The radar
The Sioux Falls radar (KFSD), 81 km from the middle of the area, began a volume at 06:12 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 27, 1:36 AM CDT | TSTM WND GST 64 | 1 E Le Mars, IA | DELAYED REPORT. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 26, 8:03 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 6.2 hours before the alert went out and 209 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
- 5342 J/kg
- Mixed-layer CIN
- -16 J/kg
- Mixed-layer LCL
- 1163 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 111 m²/s²
- 0-3 km storm-relative helicity
- 199 m²/s²
- Significant tornado parameter
- 3.8
- Supercell composite
- 24.0
The text
As transmitted.
520
WUUS53 KFSD 270609
SVRFSD
IAC035-119-141-143-149-167-270700-
/O.NEW.KFSD.SV.W.0113.210827T0609Z-210827T0700Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
109 AM CDT Fri Aug 27 2021
The National Weather Service in Sioux Falls has issued a
* Severe Thunderstorm Warning for...
Northwestern Cherokee County in northwestern Iowa...
Southeastern Lyon County in northwestern Iowa...
Osceola County in northwestern Iowa...
Sioux County in northwestern Iowa...
Northeastern Plymouth County in northwestern Iowa...
O'Brien County in northwestern Iowa...
* Until 200 AM CDT.
* At 109 AM CDT, severe thunderstorms were located along a line
extending from Doon to near Sioux Center to near Struble, moving
east at 45 mph.
HAZARD...70 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect considerable tree damage. Damage is likely to
mobile homes, roofs, and outbuildings.
* Severe thunderstorms will be near...
Boyden and Hospers around 120 AM CDT.
Remsen, George and Matlock around 125 AM CDT.
Other locations in the path of these severe thunderstorms include
Sheldon, Alton, Archer, Granville, Sibley, Sanborn, Ashton, Melvin,
Hartley, Paullina, Primghar and Ocheyedan.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4349 9558 4324 9545 4281 9572 4277 9638
4307 9623 4332 9639
TIME...MOT...LOC 0609Z 251DEG 39KT 4327 9620 4310 9609 4286 9623
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
SG1 follow-up statement
446
WWUS53 KFSD 270629
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
129 AM CDT Fri Aug 27 2021
IAC035-119-141-143-149-167-270700-
/O.CON.KFSD.SV.W.0113.000000T0000Z-210827T0700Z/
Cherokee IA-Lyon IA-Osceola IA-Sioux IA-Plymouth IA-O'Brien IA-
129 AM CDT Fri Aug 27 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 AM CDT
FOR NORTHWESTERN CHEROKEE...SOUTHEASTERN LYON...OSCEOLA...EASTERN
SIOUX...NORTHEASTERN PLYMOUTH AND O'BRIEN COUNTIES...
At 129 AM CDT, severe thunderstorms were located along a line
extending from George to Sheldon to near Alton, moving east at 45
mph.
HAZARD...70 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect considerable tree damage. Damage is likely to mobile
homes, roofs, and outbuildings.
Locations impacted include...
Sheldon, Archer, Ashton, Sibley, Sanborn, Melvin, Hartley,
Paullina, Primghar and Ocheyedan.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4349 9558 4324 9545 4281 9572 4279 9614
4309 9611 4336 9622
TIME...MOT...LOC 0629Z 250DEG 38KT 4333 9598 4316 9587 4292 9601
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
SGThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 12:17 AM CDT | Severe Thunderstorm Warning | FSD | Lyon, Sioux | 28 min |
| Aug 27, 12:34 AM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Sioux | 41 min |
| Aug 27, 1:04 AM CDT | Tornado Warning | FSD | Sioux | 26 min |
| Aug 27, 1:25 AM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida, Plymouth, Woodbury | 50 min |
| Aug 27, 1:52 AM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Clay, Dickinson, O'Brien, Osceola | 68 min |
| Aug 27, 2:00 AM CDT | Severe Thunderstorm Warning | FSD | Buena Vista | 60 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.