Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 89, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 20, 2021, 6:31 PM CDT for Ida County, Woodbury County, Iowa. It was in force for 29 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 20, 2021, 6:31 PM CDT (23:31 UTC)
- Expired
- Aug 20, 2021, 7:00 PM CDT
- In force
- 29 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Hail
- 0.88 in
- Wind
- 60.0 mph
Counties Ida County, IA, Woodbury County, IA
The radar
The Omaha radar (KOAX), 119 km from the middle of the area, began a volume at 23:30 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 20, 3:58 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 12:00Z, 11.5 hours before the alert went out and 119 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
- 950 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 534 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 121 m²/s²
- 0-3 km storm-relative helicity
- 99 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
063
WUUS53 KFSD 202331
SVRFSD
IAC093-193-210000-
/O.NEW.KFSD.SV.W.0089.210820T2331Z-210821T0000Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
631 PM CDT Fri Aug 20 2021
The National Weather Service in Sioux Falls has issued a
* Severe Thunderstorm Warning for...
Southeastern Woodbury County in west central Iowa...
Central Ida County in west central Iowa...
* Until 700 PM CDT.
* At 631 PM CDT, a severe thunderstorm was located near Anthon, or 17
miles west of Ida Grove, moving northeast at 40 mph.
HAZARD...60 mph wind gusts and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* This severe thunderstorm will be near...
Battle Creek around 645 PM CDT.
Ida Grove around 655 PM CDT.
Holstein around 700 PM CDT.
Other locations impacted by this severe thunderstorm include Oto.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4228 9601 4253 9553 4231 9543 4221 9587
4221 9596
TIME...MOT...LOC 2331Z 238DEG 35KT 4230 9582
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Schumacher2 follow-up statements
279
WWUS53 KFSD 202347
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
647 PM CDT Fri Aug 20 2021
IAC093-193-210000-
/O.CON.KFSD.SV.W.0089.000000T0000Z-210821T0000Z/
Woodbury IA-Ida IA-
647 PM CDT Fri Aug 20 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM CDT
FOR SOUTHEASTERN WOODBURY AND CENTRAL IDA COUNTIES...
At 647 PM CDT, a severe thunderstorm was located near Battle Creek,
or 9 miles west of Ida Grove, moving northeast at 40 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
This severe storm will be near...
Ida Grove around 655 PM CDT.
Holstein around 700 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4233 9586 4253 9553 4231 9543 4222 9583
4224 9585
TIME...MOT...LOC 2347Z 238DEG 35KT 4238 9564
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Schumacher831
WWUS53 KFSD 202357
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
657 PM CDT Fri Aug 20 2021
IAC093-193-210007-
/O.EXP.KFSD.SV.W.0089.000000T0000Z-210821T0000Z/
Woodbury IA-Ida IA-
657 PM CDT Fri Aug 20 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN WOODBURY AND
CENTRAL IDA COUNTIES WILL EXPIRE AT 700 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 gusty
winds are still possible with this thunderstorm.
A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
west central Iowa.
LAT...LON 4233 9586 4253 9553 4231 9543 4222 9583
4224 9585
TIME...MOT...LOC 2357Z 238DEG 35KT 4242 9555
$$
SchumacherThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 6:13 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Plymouth, Woodbury | 32 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.