Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 102, NWS La Crosse, WI

September 20, 20215 counties in Minnesota

NWS La Crosse, WI issued this severe thunderstorm warning at Sep 20, 2021, 4:30 PM CDT for 5 counties in Minnesota. It was in force for 45 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: Sep 20, 2021, 4:30 PM CDT (21:30 UTC)
Expired: Sep 20, 2021, 5:15 PM CDT
In force: 45 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Fillmore County, MN, Mower County, MN, Olmsted County, MN, Wabasha County, MN, Winona County, MN

The radar

The La Crosse radar (KARX), 81 km from the middle of the area, began a volume at 21:28 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 20, 4:30 PM CDT	TSTM WND GST 45	3 N Stewartville, MN	MESONET STATION MN070 3 N STEWARTVILLE.
Sep 20, 4:50 PM CDT	TSTM WND GST 39	2 Sse Eyota, MN	MESONET STATION MN011 JCT CR 7 I-90 MILE POST 226.

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
Sep 20, 2:07 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 9.5 hours before the alert went out and 148 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: 148 J/kg
Mixed-layer CIN: -141 J/kg
Mixed-layer LCL: 1002 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 210 m²/s²
0-3 km storm-relative helicity: 162 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

As transmitted.

697 
WUUS53 KARX 202130
SVRARX
MNC045-099-109-157-169-202215-
/O.NEW.KARX.SV.W.0102.210920T2130Z-210920T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service La Crosse WI
430 PM CDT Mon Sep 20 2021

The National Weather Service in La Crosse has issued a

* Severe Thunderstorm Warning for...
  Western Winona County in southeastern Minnesota...
  Southeastern Olmsted County in southeastern Minnesota...
  Northeastern Mower County in southeastern Minnesota...
  South central Wabasha County in southeastern Minnesota...
  Northwestern Fillmore County in southeastern Minnesota...

* Until 515 PM CDT.

* At 430 PM CDT, severe thunderstorms were located along a line
  extending from Rochester to near Stewartville to 7 miles northwest
  of Spring Valley, moving northeast at 35 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Severe thunderstorms will be near...
  Eyota around 450 PM CDT.
  Chatfield and Dover around 455 PM CDT.
  St. Charles around 500 PM CDT.
  Lewiston, Rollingstone and Altura around 515 PM CDT.

This includes Interstate 90 in Minnesota between mile markers 210 and
243.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4419 9199 4412 9178 4386 9189 4373 9253
      4389 9249 4400 9253
TIME...MOT...LOC 2130Z 245DEG 29KT 4400 9247 4393 9241 4377 9246 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Skow

3 follow-up statements

033 
WWUS53 KARX 202142
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
442 PM CDT Mon Sep 20 2021

MNC099-202151-
/O.CAN.KARX.SV.W.0102.000000T0000Z-210920T2215Z/
Mower MN-
442 PM CDT Mon Sep 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN MOWER COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southeastern Minnesota.

LAT...LON 4419 9199 4412 9178 4386 9189 4376 9242
      4393 9240 4405 9240
TIME...MOT...LOC 2141Z 244DEG 29KT 4407 9227 4396 9231 4380 9236 

$$

MNC045-109-157-169-202215-
/O.CON.KARX.SV.W.0102.000000T0000Z-210920T2215Z/
Winona MN-Olmsted MN-Wabasha MN-Fillmore MN-
442 PM CDT Mon Sep 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR WESTERN WINONA...SOUTHEASTERN OLMSTED...SOUTH CENTRAL WABASHA AND
NORTHWESTERN FILLMORE COUNTIES...

At 441 PM CDT, severe thunderstorms were located along a line
extending from near Elgin to near Eyota to 7 miles southeast of
Stewartville, moving northeast at 35 mph.

HAZARD...60 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

These severe storms will be near...
  Eyota around 450 PM CDT.

Other locations in the path of these severe thunderstorms include
Dover, St. Charles, Chatfield, Altura, Lewiston and Rollingstone.

This includes Interstate 90 in Minnesota between mile markers 215 and
243.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4419 9199 4412 9178 4386 9189 4376 9242
      4393 9240 4405 9240
TIME...MOT...LOC 2141Z 244DEG 29KT 4407 9227 4396 9231 4380 9236 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Skow

395 
WWUS53 KARX 202157
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
457 PM CDT Mon Sep 20 2021

MNC045-202207-
/O.CAN.KARX.SV.W.0102.000000T0000Z-210920T2215Z/
Fillmore MN-
457 PM CDT Mon Sep 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN FILLMORE COUNTY
IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southeastern Minnesota.

LAT...LON 4419 9199 4412 9178 4386 9189 4385 9227
      4403 9222 4411 9222
TIME...MOT...LOC 2157Z 236DEG 42KT 4415 9211 4410 9206 4385 9216 

$$

MNC109-157-169-202215-
/O.CON.KARX.SV.W.0102.000000T0000Z-210920T2215Z/
Winona MN-Olmsted MN-Wabasha MN-
457 PM CDT Mon Sep 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR WESTERN WINONA...SOUTHEASTERN OLMSTED AND SOUTH CENTRAL WABASHA
COUNTIES...

At 457 PM CDT, severe thunderstorms were located along a line
extending from near Plainview to 6 miles west of Altura to Chatfield,
moving northeast at 50 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

These severe storms will be near...
  Altura around 505 PM CDT.
  St. Charles around 510 PM CDT.
  Lewiston around 520 PM CDT.
  Rollingstone around 525 PM CDT.

This includes Interstate 90 in Minnesota between mile markers 224 and
243.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4419 9199 4412 9178 4386 9189 4385 9227
      4403 9222 4411 9222
TIME...MOT...LOC 2157Z 236DEG 42KT 4415 9211 4410 9206 4385 9216 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Skow

853 
WWUS53 KARX 202211
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
511 PM CDT Mon Sep 20 2021

MNC109-157-169-202221-
/O.EXP.KARX.SV.W.0102.000000T0000Z-210920T2215Z/
Winona MN-Olmsted MN-Wabasha MN-
511 PM CDT Mon Sep 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN WINONA...SOUTHEASTERN
OLMSTED AND SOUTH CENTRAL WABASHA COUNTIES WILL EXPIRE AT 515 PM
CDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southeastern Minnesota.

LAT...LON 4419 9199 4412 9178 4386 9189 4385 9227
      4403 9222 4411 9222
TIME...MOT...LOC 2211Z 245DEG 29KT 4419 9198 4414 9193 4389 9203 

$$

Skow

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 20, 3:23 PM CDT	Special Weather Statement	ARX	Mower	37 min
Sep 20, 3:47 PM CDT	Severe Thunderstorm Warning	ARX	Dodge, Fillmore, Mower, Olmsted	43 min
Sep 20, 5:03 PM CDT	Tornado Warning	ARX	Fillmore	27 min
Sep 20, 5:12 PM CDT	Special Weather Statement	ARX	Winona	33 min
Sep 20, 5:38 PM CDT	Special Weather Statement	ARX	Houston	37 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.