Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 126, NWS Sioux Falls, SD

August 28, 20214 counties in Minnesota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 28, 2021, 5:45 PM CDT for 4 counties in Minnesota. It was in force for 45 min. 9 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: Aug 28, 2021, 5:45 PM CDT (22:45 UTC)
Expired: Aug 28, 2021, 6:30 PM CDT
In force: 45 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 Cottonwood County, MN, Jackson County, MN, Murray County, MN, Nobles County, MN

The radar

The Sioux Falls radar (KFSD), 119 km from the middle of the area, began a volume at 22:50 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 28, 5:45 PM CDT	TSTM WND DMG	Avoca, MN	REPORT VIA SOCIAL MEDIA OF HEAVY TREE DAMAGE IN AVOCA.
Aug 28, 5:45 PM CDT	TSTM WND GST 55	Worthington, MN	WALL CLOUD PUSHED ACROSS TOWN, SWITCHING WINDS FROM NEARLY CALM TO GUSTY AT 44 TO 55 MPH.
Aug 28, 5:46 PM CDT	TSTM WND DMG	1 S Westbrook, MN	GRAIN BIN DAMAGED 1/2 MILE SOUTH OF WESTBROOK. DAMAGE ALSO TO OLD BARN 1 SOUTH OF WESTBROOK.
Aug 28, 5:50 PM CDT	TSTM WND DMG	Westbrook, MN	DAMAGE TO WESTBROOK LUMBER BUILDING. WIND GUSTS ESTIMATED AT 70 MPH.
Aug 28, 5:54 PM CDT	TSTM WND DMG	1 S Storden, MN	GRAIN BIN DAMAGE 1/2 MILE SOUTH OF STORDEN.
Aug 28, 6:03 PM CDT	TSTM WND DMG	Jeffers, MN	LARGE TREE, ROUGHLY ONE TO TWO FEET IN DIAMETER, SNAPPED IN HALF. PICTURE VIA SOCIAL MEDIA.
Aug 28, 6:06 PM CDT	TSTM WND DMG	Windom, MN	REPORT FROM MPING: TREES UPROOTED OR SNAPPED; ROOF BLOWN OFF.
Aug 28, 6:06 PM CDT	TSTM WND GST 66	2 Nne Windom, MN	DELAYED REPORT. AWOS STATION KMWM WINDOM MUNICIPAL AIRPORT REPORTED GUST OF 66 MPH.
Aug 28, 6:16 PM CDT	TSTM WND DMG	4 S Westbrook, MN	NUMEROUS TREES DOWN AND LAYING ACROSS ROAD.

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 28, 3:44 PM CDT	Tornado Watch	SPC	5 hr
Aug 28, 3:57 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.8 hours before the alert went out and 172 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1550 J/kg
Mixed-layer CIN: -130 J/kg
Mixed-layer LCL: 676 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 139 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.3

Open this sounding in Storm Lab

The text

As transmitted.

232 
WUUS53 KFSD 282245
SVRFSD
MNC033-063-101-105-282330-
/O.NEW.KFSD.SV.W.0126.210828T2245Z-210828T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
545 PM CDT Sat Aug 28 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Jackson County in southwestern Minnesota...
  Eastern Nobles County in southwestern Minnesota...
  Eastern Murray County in southwestern Minnesota...
  Cottonwood County in southwestern Minnesota...

* Until 630 PM CDT.

* At 545 PM CDT, severe thunderstorms were located along a line
  extending from near Dovray to near Worthington, moving east at 55
  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...
  Round Lake and Dovray around 550 PM CDT.
  Westbrook around 555 PM CDT.
  Storden around 600 PM CDT.
  Jeffers around 605 PM CDT.
  Lakefield around 610 PM CDT.
  Kilen Woods State Park around 615 PM CDT.
  Jackson In Jackson County and Comfrey around 620 PM CDT.

Other locations impacted by these severe thunderstorms include Avoca,
Delft, Kinbrae, Alpha, Wilder, Dundee and Okabena.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM CDT for southwestern
Minnesota.

For your protection move to an interior room on the lowest floor of a
building.

A Tornado Watch remains in effect until 900 PM CDT for southwestern
Minnesota.

&&

LAT...LON 4350 9564 4418 9567 4420 9563 4419 9511
      4411 9510 4411 9486 4350 9485
TIME...MOT...LOC 2245Z 261DEG 48KT 4402 9558 4357 9560 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

APT

2 follow-up statements

172 
WWUS53 KFSD 282307
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
607 PM CDT Sat Aug 28 2021

MNC033-063-101-105-282330-
/O.CON.KFSD.SV.W.0126.000000T0000Z-210828T2330Z/
Jackson MN-Nobles MN-Murray MN-Cottonwood MN-
607 PM CDT Sat Aug 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM CDT
FOR NORTHERN JACKSON...NORTHEASTERN NOBLES...EASTERN MURRAY AND
COTTONWOOD COUNTIES...

At 607 PM CDT, severe thunderstorms were located along a line
extending from 6 miles southeast of Lamberton to Lakefield, moving
east at 55 mph.

HAZARD...70 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

These severe storms will be near...
  Bergen and Kilen Woods State Park around 615 PM CDT.
  Comfrey around 620 PM CDT.

Other locations impacted by these severe thunderstorms include
Kinbrae, Wilder, Dundee, Avoca, Delft and Okabena.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM CDT for southwestern
Minnesota.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4366 9564 4418 9567 4420 9563 4419 9511
      4411 9510 4411 9486 4366 9485
TIME...MOT...LOC 2307Z 269DEG 49KT 4416 9517 4369 9518 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

APT

110 
WWUS53 KFSD 282331 RRA
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
631 PM CDT Sat Aug 28 2021

MNC033-063-101-105-282341-
/O.EXP.KFSD.SV.W.0126.000000T0000Z-210828T2330Z/
Jackson MN-Nobles MN-Murray MN-Cottonwood MN-
631 PM CDT Sat Aug 28 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN JACKSON...
NORTHEASTERN NOBLES...EASTERN MURRAY AND COTTONWOOD COUNTIES HAS
EXPIRED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been allowed to expire.  However gusty
winds are still possible with these thunderstorms.

A Tornado Watch remains in effect until 900 PM CDT for southwestern
Minnesota.

LAT...LON 4366 9564 4418 9567 4420 9563 4419 9511
      4411 9510 4411 9486 4366 9485
TIME...MOT...LOC 2331Z 261DEG 48KT 4421 9473 4374 9475 

$$

APT

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 28, 4:45 PM CDT	Tornado Warning	FSD	Rock	30 min
Aug 28, 4:49 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Nobles, Rock	41 min
Aug 28, 5:00 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Nobles, Rock	45 min
Aug 28, 5:06 PM CDT	Tornado Warning	FSD	Murray, Nobles, Pipestone, Rock	24 min
Aug 28, 5:24 PM CDT	Tornado Warning	FSD	Nobles	36 min
Aug 28, 5:26 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Cottonwood, Jackson, Murray, Nobles, Pipestone, Rock	34 min
Aug 28, 5:26 PM CDT	Tornado Warning	FSD	Cottonwood, Murray	34 min
Aug 28, 5:29 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Cottonwood, Jackson, Murray, Nobles, Pipestone, Rock	31 min
Aug 28, 5:34 PM CDT	Severe Thunderstorm Warning	FSD	Rock	17 min
Aug 28, 5:43 PM CDT	Tornado Warning	FSD	Cottonwood, Murray	32 min
Aug 28, 5:49 PM CDT	Tornado Warning	FSD	Cottonwood, Jackson, Murray, Nobles	26 min
Aug 28, 6:01 PM CDT	Tornado Warning	FSD	Cottonwood	30 min
Aug 28, 6:15 PM CDT	Severe Thunderstorm Warning	FSD	Pipestone, Rock	45 min
Aug 28, 6:53 PM CDT	Severe Thunderstorm Warning	FSD	Rock	52 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2021 Every 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.