Alert archive / Wisconsin / Tornado Warnings in 2021

Tornado Warning 19, NWS La Crosse, WI

September 20, 2021Clark County, Trempealeau County, Wisconsin

NWS La Crosse, WI issued this tornado warning at Sep 20, 2021, 6:11 PM CDT for Clark County, Trempealeau County, Wisconsin. It was in force for 19 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: Sep 20, 2021, 6:11 PM CDT (23:11 UTC)
Expired: Sep 20, 2021, 6:30 PM CDT
In force: 19 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Tornado: Observed
Hail: 0.75 in

Counties Clark County, WI, Trempealeau County, WI

The radar

The La Crosse radar (KARX), 99 km from the middle of the area, began a volume at 23:11 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 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, 11.2 hours before the alert went out and 201 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.

962 
WFUS53 KARX 202311
TORARX
WIC019-121-202330-
/O.NEW.KARX.TO.W.0019.210920T2311Z-210920T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service La Crosse WI
611 PM CDT Mon Sep 20 2021

The National Weather Service in La Crosse has issued a

* Tornado Warning for...
  West central Clark County in central Wisconsin...
  Northeastern Trempealeau County in west central Wisconsin...

* Until 630 PM CDT.
    
* At 611 PM CDT, a tornado producing storm was located near Strum, or
  11 miles north of Whitehall, moving northeast at 35 mph.

  HAZARD...Damaging tornado.

  SOURCE...Radar confirmed tornado.

  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 tornadic storm will be near...
  Osseo around 620 PM CDT.

Other locations impacted by this tornadic thunderstorm include The
Blue Swamp.

This includes Interstate 94 between mile markers 88 and 89.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

This cluster of thunderstorms is capable of producing tornadoes and
widespread significant wind damage. Do not wait to see or hear the
tornado. For your protection move to an interior room on the lowest
floor of a building.

&&

LAT...LON 4487 9075 4446 9133 4451 9143 4460 9137
      4460 9116 4475 9093 4478 9092 4496 9092
TIME...MOT...LOC 2311Z 216DEG 32KT 4453 9134 

TORNADO...OBSERVED
MAX HAIL SIZE...<.75 IN

$$

Skow

2 follow-up statements

393 
WWUS53 KARX 202312
SVSARX

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

WIC019-202322-
/O.CAN.KARX.TO.W.0019.000000T0000Z-210920T2330Z/
Clark WI-
612 PM CDT Mon Sep 20 2021

...THE TORNADO WARNING FOR WEST CENTRAL CLARK COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
west central Wisconsin.

LAT...LON 4458 9116 4446 9133 4451 9143 4460 9137
      4459 9117
TIME...MOT...LOC 2312Z 216DEG 32KT 4454 9133 

$$

WIC121-202330-
/O.CON.KARX.TO.W.0019.000000T0000Z-210920T2330Z/
Trempealeau WI-
612 PM CDT Mon Sep 20 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 630 PM CDT FOR
NORTHEASTERN TREMPEALEAU COUNTY...
        
At 612 PM CDT, a confirmed tornado was located over Strum, or 12
miles north of Whitehall, moving northeast at 35 mph.

HAZARD...Damaging tornado.

SOURCE...Radar confirmed tornado.

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 tornado will be near...
  Osseo around 620 PM CDT.

This includes Interstate 94 between mile markers 88 and 89.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

This cluster of thunderstorms is capable of producing tornadoes and
widespread significant wind damage. Do not wait to see or hear the
tornado. For your protection move to an interior room on the lowest
floor of a building.

&&

LAT...LON 4458 9116 4446 9133 4451 9143 4460 9137
      4459 9117
TIME...MOT...LOC 2312Z 216DEG 32KT 4454 9133 

TORNADO...OBSERVED
MAX HAIL SIZE...<.75 IN

$$

Skow

644 
WWUS53 KARX 202324
SVSARX

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

WIC121-202334-
/O.EXP.KARX.TO.W.0019.000000T0000Z-210920T2330Z/
Trempealeau WI-
624 PM CDT Mon Sep 20 2021

...THE TORNADO WARNING FOR NORTHEASTERN TREMPEALEAU COUNTY WILL
EXPIRE AT 630 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
west central Wisconsin.

LAT...LON 4458 9116 4446 9133 4451 9143 4460 9137
      4459 9117
TIME...MOT...LOC 2324Z 216DEG 32KT 4462 9125 

$$

Skow

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 20, 5:12 PM CDT	Special Weather Statement	ARX	Buffalo	33 min
Sep 20, 5:38 PM CDT	Special Weather Statement	ARX	La Crosse, Trempealeau	37 min
Sep 20, 5:46 PM CDT	Tornado Warning	ARX	Buffalo, Trempealeau	29 min
Sep 20, 6:18 PM CDT	Special Weather Statement	ARX	Jackson, La Crosse, Monroe, Vernon	42 min

Nearby

Tornado Warnings in Wisconsin, 2021 Every tornado warning in 2021 Tornadoes 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.