Alert archive / Iowa / Tornado Warnings in 2021
Tornado Warning 5, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at Aug 8, 2021, 7:15 PM CDT for Buena Vista County, Clay County, Iowa. It was in force for 45 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 8, 2021, 7:15 PM CDT (00:15 UTC)
- Expired
- Aug 8, 2021, 8:00 PM CDT
- In force
- 45 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.75 in
Counties Buena Vista County, IA, Clay County, IA
The radar
The Sioux Falls radar (KFSD), 158 km from the middle of the area, began a volume at 00:18 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
Omaha, NE (KOAX), launched 00:00Z, 0.3 hours before the alert went out and 198 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
- 1733 J/kg
- Mixed-layer CIN
- -130 J/kg
- Mixed-layer LCL
- 1356 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 137 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 6.0
The text
As transmitted.
504
WFUS53 KFSD 090015
TORFSD
IAC021-041-090100-
/O.NEW.KFSD.TO.W.0005.210809T0015Z-210809T0100Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
715 PM CDT Sun Aug 8 2021
The National Weather Service in Sioux Falls has issued a
* Tornado Warning for...
Northeastern Buena Vista County in northwestern Iowa...
South central Clay County in northwestern Iowa...
* Until 800 PM CDT.
* At 714 PM CDT, a severe thunderstorm capable of producing a
tornado was located just north of Sioux Rapids, or 15 miles south
of Spencer In Clay County, moving southeast at 15 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation. This storm has had a history of
producing brief tornadoes.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* This dangerous storm will be near...
Sioux Rapids around 725 PM CDT.
Other locations in the path of this tornadic thunderstorm include
Marathon and Albert City.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4269 9516 4296 9530 4300 9505 4287 9491
4274 9492
TIME...MOT...LOC 0014Z 326DEG 12KT 4292 9517
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Kalin2 follow-up statements
398
WWUS53 KFSD 090037
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
737 PM CDT Sun Aug 8 2021
IAC041-090046-
/O.CAN.KFSD.TO.W.0005.000000T0000Z-210809T0100Z/
Clay IA-
737 PM CDT Sun Aug 8 2021
...THE TORNADO WARNING FOR SOUTH CENTRAL CLAY COUNTY IS CANCELLED...
The tornadic thunderstorm which prompted the warning has moved out
of the warned area. Therefore, the warning has been cancelled.
LAT...LON 4269 9516 4289 9520 4291 9495 4287 9491
4274 9492
TIME...MOT...LOC 0036Z 324DEG 16KT 4282 9507
$$
IAC021-090100-
/O.CON.KFSD.TO.W.0005.000000T0000Z-210809T0100Z/
Buena Vista IA-
737 PM CDT Sun Aug 8 2021
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 800 PM CDT FOR
NORTHEASTERN BUENA VISTA COUNTY...
At 736 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Marathon, or 13 miles northeast of Storm Lake,
moving southeast at 20 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
Locations impacted include...
Albert City.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4269 9516 4289 9520 4291 9495 4287 9491
4274 9492
TIME...MOT...LOC 0036Z 324DEG 16KT 4282 9507
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Kalin613
WWUS53 KFSD 090059
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
759 PM CDT Sun Aug 8 2021
IAC021-090108-
/O.EXP.KFSD.TO.W.0005.000000T0000Z-210809T0100Z/
Buena Vista IA-
759 PM CDT Sun Aug 8 2021
...THE TORNADO WARNING FOR NORTHEASTERN BUENA VISTA COUNTY WILL
EXPIRE AT 800 PM CDT...
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing an immediate
tornado. Therefore, the warning will be allowed to expire.
LAT...LON 4269 9516 4289 9520 4291 9495 4287 9491
4274 9492
TIME...MOT...LOC 0058Z 326DEG 12KT 4276 9502
$$
KalinNearby
Tornado Warnings in Iowa, 2021Every tornado warning in 2021Tornadoes 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.