Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 166, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Sep 17, 2021, 1:23 AM CDT for 6 counties in Iowa; Jackson County, Nobles County, Minnesota. It was in force for 67 min. 11 reports 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
- Sep 17, 2021, 1:23 AM CDT (06:23 UTC)
- Expired
- Sep 17, 2021, 2:30 AM CDT
- In force
- 67 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Clay County, IA, Dickinson County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Sioux County, IA, Jackson County, MN, Nobles County, MN
The radar
The Sioux Falls radar (KFSD), 114 km from the middle of the area, began a volume at 06:26 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 |
|---|---|---|---|
| Sep 17, 1:26 AM CDT | TSTM WND GST 64 | 3 Nne Sheldon, IA | AWOS STATION KSHL SHELDON AIRPORT. |
| Sep 17, 1:28 AM CDT | TSTM WND GST 64 | 1 Ne Ashton, IA | REPORT FOR IOWA RWIS. |
| Sep 17, 1:29 AM CDT | TSTM WND DMG | 2 Ene Sheldon, IA | ROOF COMPLETELY REMOVED FROM STRIP MALL AND DEPOSITED IN PIECES ON ROADWAY. |
| Sep 17, 1:33 AM CDT | TSTM WND DMG | 1 Sw Boyden, IA | POWER LINES DOWN. TIME ESTIMATED FROM RADAR. |
| Sep 17, 1:33 AM CDT | TSTM WND DMG | Hull, IA | LARGE CONSTRUCTION SHED LIFTED AND COLLAPSED IN NEARBY CORN FIELD. TIME ESTIMATED FROM RADAR. |
| Sep 17, 1:34 AM CDT | TSTM WND DMG | Boyden, IA | LARGE TREE BRANCHES DOWN. TIME ESTIMATED FROM RADAR. |
| Sep 17, 1:34 AM CDT | TSTM WND DMG | Boyden, IA | SCHOOL BUS GARAGE HEAVILY DAMAGED. TIME ESTIMATED FROM RADAR. |
| Sep 17, 1:40 AM CDT | TSTM WND DMG | Lakefield, MN | TREES DOWN FROM DAMAGING WINDS. |
| Sep 17, 1:45 AM CDT | TSTM WND DMG | 5 Nw Sanborn, IA | LARGE TREE LIMBS DOWN. TIME ESTIMATED FROM RADAR. |
| Sep 17, 1:53 AM CDT | TSTM WND GST 51 | 1 Ene Jackson, MN | AWOS STATION KMJQ JACKSON AIRPORT. |
| Sep 17, 2:04 AM CDT | TSTM WND GST 54 | 4 Wnw Spencer, IA | ASOS STATION KSPW SPENCER MUNICIPAL AIRPORT. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 6.4 hours before the alert went out and 254 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
- 612 J/kg
- Mixed-layer CIN
- -165 J/kg
- Mixed-layer LCL
- 2155 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 19 m²/s²
- 0-3 km storm-relative helicity
- 132 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
666
WUUS53 KFSD 170623
SVRFSD
IAC041-059-119-141-143-167-MNC063-105-170730-
/O.NEW.KFSD.SV.W.0166.210917T0623Z-210917T0730Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
123 AM CDT Fri Sep 17 2021
The National Weather Service in Sioux Falls has issued a
* Severe Thunderstorm Warning for...
Eastern Lyon County in northwestern Iowa...
Osceola County in northwestern Iowa...
Dickinson County in northwestern Iowa...
Northeastern Sioux County in northwestern Iowa...
Northern Clay County in northwestern Iowa...
Northern O'Brien County in northwestern Iowa...
Jackson County in southwestern Minnesota...
Nobles County in southwestern Minnesota...
* Until 230 AM CDT.
* At 123 AM CDT, severe thunderstorms were located along a line
extending from 6 miles southeast of Fulda to near Sibley to near
Hospers, moving east at 50 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* Severe thunderstorms will be near...
Brewster around 130 AM CDT.
Heron Lake and Ocheyedan around 135 AM CDT.
Sanborn, Round Lake and Harris around 140 AM CDT.
Other locations in the path of these severe thunderstorms include
Lake Park, Hartley, Milford, Okoboji, Wahpeton, Kilen Woods State
Park, Spirit Lake, Arnolds Park, Orleans, Everly, West Okoboji,
Spencer In Clay County, Fostoria and Superior.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4350 9491 4313 9491 4314 9627 4345 9601
4379 9592 4379 9485 4350 9485
TIME...MOT...LOC 0623Z 265DEG 43KT 4379 9554 4343 9570 4310 9593
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH
$$
SG3 follow-up statements
113
WWUS53 KFSD 170649
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
149 AM CDT Fri Sep 17 2021
IAC119-170659-
/O.CAN.KFSD.SV.W.0166.000000T0000Z-210917T0730Z/
Lyon IA-
149 AM CDT Fri Sep 17 2021
...THE SEVERE THUNDERSTORM WARNING FOR EASTERN LYON COUNTY IS
CANCELLED...
The storms which prompted the warning have moved out of the warned
area. Therefore, the warning has been cancelled.
LAT...LON 4350 9491 4313 9491 4314 9599 4326 9594
4326 9586 4342 9586 4378 9574 4379 9485
4350 9485
TIME...MOT...LOC 0649Z 265DEG 43KT 4381 9514 4345 9530 4313 9554
$$
IAC041-059-141-143-167-MNC063-105-170730-
/O.CON.KFSD.SV.W.0166.000000T0000Z-210917T0730Z/
Osceola IA-Dickinson IA-Sioux IA-Clay IA-O'Brien IA-Jackson MN-
Nobles MN-
149 AM CDT Fri Sep 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 AM CDT
FOR OSCEOLA...DICKINSON...NORTHEASTERN SIOUX...NORTHERN CLAY...
NORTHERN O'BRIEN...JACKSON AND EASTERN NOBLES COUNTIES...
At 149 AM CDT, severe thunderstorms were located along a line
extending from near Windom to Lake Park to near Hartley, moving east
at 50 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Okoboji, Wahpeton, Kilen Woods State Park, Spirit Lake, Milford,
Arnolds Park, Orleans, West Okoboji, Superior, Spencer In Clay
County, Fostoria and Lost Island Lake.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4350 9491 4313 9491 4314 9599 4326 9594
4326 9586 4342 9586 4378 9574 4379 9485
4350 9485
TIME...MOT...LOC 0649Z 265DEG 43KT 4381 9514 4345 9530 4313 9554
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH
$$
SG094
WWUS53 KFSD 170704
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
204 AM CDT Fri Sep 17 2021
IAC167-MNC105-170714-
/O.CAN.KFSD.SV.W.0166.000000T0000Z-210917T0730Z/
Sioux IA-Nobles MN-
204 AM CDT Fri Sep 17 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN SIOUX AND EASTERN
NOBLES COUNTIES IS CANCELLED...
The storms which prompted the warning have weakened. moved out of
the warned area. Therefore, the warning has been cancelled.
LAT...LON 4350 9491 4313 9491 4314 9558 4343 9543
4378 9530 4379 9485 4350 9485
TIME...MOT...LOC 0704Z 265DEG 43KT 4382 9493 4346 9509 4314 9533
$$
IAC041-059-141-143-MNC063-170730-
/O.CON.KFSD.SV.W.0166.000000T0000Z-210917T0730Z/
Osceola IA-Dickinson IA-Clay IA-O'Brien IA-Jackson MN-
204 AM CDT Fri Sep 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 AM CDT
FOR EASTERN OSCEOLA...DICKINSON...NORTHERN CLAY...NORTHEASTERN
O'BRIEN AND JACKSON COUNTIES...
At 204 AM CDT, severe thunderstorms were located along a line
extending from near Bergen to Orleans to Everly, moving east at 50
mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Spencer In Clay County, Spirit Lake, Jackson In Jackson County,
Milford, Lakefield, Hartley, Arnolds Park, Lake Park, Okoboji,
Orleans, Everly, Terril, Wahpeton, West Okoboji, Fostoria, Superior,
Kilen Woods State Park, Lost Island Lake, Okabena and Dickens.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4350 9491 4313 9491 4314 9558 4343 9543
4378 9530 4379 9485 4350 9485
TIME...MOT...LOC 0704Z 265DEG 43KT 4382 9493 4346 9509 4314 9533
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH
$$
SG048
WWUS53 KFSD 170721
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
221 AM CDT Fri Sep 17 2021
IAC041-059-141-143-MNC063-170731-
/O.EXP.KFSD.SV.W.0166.000000T0000Z-210917T0730Z/
Osceola IA-Dickinson IA-Clay IA-O'Brien IA-Jackson MN-
221 AM CDT Fri Sep 17 2021
...THE SEVERE THUNDERSTORM WARNING FOR EASTERN OSCEOLA...DICKINSON...
NORTHERN CLAY...NORTHEASTERN O'BRIEN AND JACKSON COUNTIES WILL EXPIRE
AT 230 AM CDT...
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore, the warning will
be allowed to expire. However gusty winds are still possible with
these thunderstorms.
LAT...LON 4350 9491 4313 9491 4314 9558 4343 9543
4378 9530 4379 9485 4350 9485
TIME...MOT...LOC 0721Z 270DEG 43KT 4383 9469 4347 9485 4316 9509
$$
SGThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 17, 12:29 AM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Sioux | 46 min |
| Sep 17, 12:36 AM CDT | Severe Thunderstorm Warning | FSD | Clay, Dickinson, Lyon, O'Brien, Osceola, Sioux | 54 min |
| Sep 17, 1:11 AM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Clay, Ida, O'Brien, Plymouth and 2 more | 49 min |
| Sep 17, 12:10 AM CDT | Severe Thunderstorm Warning | FSD | Lincoln, Pipestone, Rock | 35 min |
| Sep 17, 12:34 AM CDT | Severe Thunderstorm Warning | FSD | Cottonwood, Jackson, Lincoln, Lyon, Murray, Nobles and 2 more | 56 min |
| Sep 17, 1:21 AM CDT | Severe Thunderstorm Warning | FSD | Cottonwood, Jackson, Lyon, Murray, Nobles | 39 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 2021Severe Thunderstorm Warnings in Minnesota, 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.