Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 42, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 5, 2021, 7:57 PM CDT for Lyon County, O'Brien County, Osceola County, Iowa. It was in force for 33 min. 2 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
- Jul 5, 2021, 7:57 PM CDT (00:57 UTC)
- Expired
- Jul 5, 2021, 8:30 PM CDT
- In force
- 33 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Lyon County, IA, O'Brien County, IA, Osceola County, IA
The radar
The Sioux Falls radar (KFSD), 92 km from the middle of the area, began a volume at 00:56 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 |
|---|---|---|---|
| Jul 5, 8:03 PM CDT | TSTM WND DMG | Ashton, IA | SEVERAL BRANCHES ESTIMATED AT 6 INCHES IN DIAMETER BROKEN DOWN BY WIND GUSTS. |
| Jul 5, 8:05 PM CDT | TSTM WND DMG | Sibley, IA | 6 TO 8 INCH DIAMETER TREE BRANCHES BROKEN DOWN BY THUNDERSTORM WIND GUSTS. |
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, 1.0 hours before the alert went out and 223 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
- 1088 J/kg
- Mixed-layer CIN
- -76 J/kg
- Mixed-layer LCL
- 1570 m above ground
- 0-6 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- 17 m²/s²
- 0-3 km storm-relative helicity
- 25 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
805
WUUS53 KFSD 060057
SVRFSD
IAC119-141-143-060130-
/O.NEW.KFSD.SV.W.0042.210706T0057Z-210706T0130Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
757 PM CDT Mon Jul 5 2021
The National Weather Service in Sioux Falls has issued a
* Severe Thunderstorm Warning for...
Southeastern Lyon County in northwestern Iowa...
Osceola County in northwestern Iowa...
Northern O'Brien County in northwestern Iowa...
* Until 830 PM CDT.
* At 756 PM CDT, a severe thunderstorm was located over Ashton, or
near Sibley, moving east at 30 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* This severe thunderstorm will be near...
Sibley around 800 PM CDT.
Melvin around 815 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4311 9544 4323 9587 4326 9586 4326 9589
4345 9584 4342 9539
TIME...MOT...LOC 0056Z 278DEG 27KT 4334 9579
HAIL...0.75IN
WIND...60MPH
$$
JM1 follow-up statement
825
WWUS53 KFSD 060117
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
817 PM CDT Mon Jul 5 2021
IAC119-141-143-060130-
/O.CON.KFSD.SV.W.0042.000000T0000Z-210706T0130Z/
Lyon IA-Osceola IA-O'Brien IA-
817 PM CDT Mon Jul 5 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM CDT
FOR SOUTHEASTERN LYON...OSCEOLA AND NORTHERN O'BRIEN COUNTIES...
At 817 PM CDT, a severe thunderstorm was located over Melvin, or 10
miles southeast of Sibley, moving east at 30 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
This severe thunderstorm will remain over mainly rural areas of
southeastern Lyon, Osceola and northern O'Brien Counties.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4311 9544 4323 9587 4326 9586 4326 9589
4345 9584 4342 9539
TIME...MOT...LOC 0117Z 278DEG 27KT 4332 9557
HAIL...0.75IN
WIND...60MPH
$$
JMThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 5, 7:16 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Osceola | 44 min |
| Jul 5, 8:24 PM CDT | Severe Thunderstorm Warning | FSD | Clay, Dickinson, O'Brien, Osceola | 66 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.