Alert archive / Wisconsin / Tornado Warnings in 2021

Tornado Warning 9, NWS La Crosse, WI

August 11, 2021Clark County, Wisconsin

NWS La Crosse, WI issued this tornado warning at Aug 11, 2021, 1:01 PM CDT for Clark County, Wisconsin. It was in force for 17 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
Aug 11, 2021, 1:01 PM CDT (18:01 UTC)
Expired
Aug 11, 2021, 1:18 PM CDT
In force
17 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.0 in

County Clark County, WI

The radar

The La Crosse radar (KARX), 134 km from the middle of the area, began a volume at 18:04 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.

IssuedProductOfficeLasted
Aug 11, 12:17 PM CDTTornado WatchSPC8 hr

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 6.0 hours before the alert went out and 187 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-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1499 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Green Bay/Straub, WI at 12:00Z on 2021-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 156 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1499 J/kg
Mixed-layer CIN
-136 J/kg
Mixed-layer LCL
678 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
156 m²/s²
0-3 km storm-relative helicity
206 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.1

Open this sounding in Storm Lab

The text

As transmitted.

986 
WFUS53 KARX 111801
TORARX
WIC019-111830-
/O.NEW.KARX.TO.W.0009.210811T1801Z-210811T1830Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service La Crosse WI
101 PM CDT Wed Aug 11 2021

The National Weather Service in La Crosse has issued a

* Tornado Warning for...
  Northeastern Clark County in central Wisconsin...

* Until 130 PM CDT.
    
* At 101 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Colby, or 17 miles south of Medford, moving east
  at 55 mph.

  HAZARD...Tornado and quarter size hail.

  SOURCE...Radar indicated rotation.

  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 dangerous storm will be near...
  Colby around 105 PM CDT.
  Abbotsford around 110 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Curtiss, Colby, Atwood and Unity.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4484 9032 4482 9051 4493 9054 4499 9031
TIME...MOT...LOC 1801Z 258DEG 49KT 4489 9043 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

JSB
4 follow-up statements
517 
WWUS53 KARX 111805
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
105 PM CDT Wed Aug 11 2021

WIC019-111830-
/O.CON.KARX.TO.W.0009.000000T0000Z-210811T1830Z/
Clark WI-
105 PM CDT Wed Aug 11 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 130 PM CDT FOR
NORTHEASTERN CLARK COUNTY...
    
At 104 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Colby, or 16 miles south of Medford, moving east at
55 mph.

HAZARD...Tornado and quarter size hail.

SOURCE...Radar indicated rotation.

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.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4484 9032 4483 9047 4493 9049 4499 9031
TIME...MOT...LOC 1804Z 258DEG 49KT 4490 9036 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

JSB
936 
WWUS53 KARX 111809
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
109 PM CDT Wed Aug 11 2021

WIC019-111830-
/O.CON.KARX.TO.W.0009.000000T0000Z-210811T1830Z/
Clark WI-
109 PM CDT Wed Aug 11 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 130 PM CDT FOR
NORTHEASTERN CLARK COUNTY...
    
At 109 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Colby, or 18 miles south of Medford, moving east at
50 mph.

HAZARD...Tornado and quarter size hail.

SOURCE...Radar indicated rotation.

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 thunderstorm will remain over mainly rural areas of
northeastern Clark County, including the following locations... Colby
and Unity.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4483 9044 4493 9045 4495 9032 4484 9032
TIME...MOT...LOC 1809Z 264DEG 41KT 4487 9033 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

JSB
529 
WWUS53 KARX 111814
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
114 PM CDT Wed Aug 11 2021

WIC019-111830-
/O.CON.KARX.TO.W.0009.000000T0000Z-210811T1830Z/
Clark WI-
114 PM CDT Wed Aug 11 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 130 PM CDT FOR
NORTHEASTERN CLARK COUNTY...
    
At 113 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Colby, or 18 miles south of Medford, moving east at
45 mph.

HAZARD...Tornado and half dollar size hail.

SOURCE...Radar indicated rotation.

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.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4483 9044 4493 9045 4495 9032 4484 9032
TIME...MOT...LOC 1813Z 264DEG 37KT 4487 9030 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.25 IN

$$

JSB
042 
WWUS53 KARX 111818
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
118 PM CDT Wed Aug 11 2021

WIC019-111828-
/O.CAN.KARX.TO.W.0009.000000T0000Z-210811T1830Z/
Clark WI-
118 PM CDT Wed Aug 11 2021

...THE TORNADO WARNING FOR NORTHEASTERN CLARK COUNTY IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 800 PM CDT for central
Wisconsin.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
La Crosse.

LAT...LON 4483 9044 4493 9045 4495 9032 4484 9032
TIME...MOT...LOC 1817Z 258DEG 49KT 4489 9020 

$$

JSB

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 9:19 PM CDTRiver Flood WarningARXLa Crosse, Trempealeau30 hr
Aug 11, 11:32 AM CDTSpecial Weather StatementARXTaylor28 min
Aug 11, 11:57 AM CDTSpecial Weather StatementARXClark, Taylor33 min
Aug 11, 12:18 PM CDTSevere Thunderstorm WarningARXTaylor42 min
Aug 11, 12:31 PM CDTSpecial Weather StatementARXClark, Jackson, La Crosse, Monroe59 min
Aug 11, 1:07 PM CDTSevere Thunderstorm WarningARXLa Crosse, Monroe38 min
Aug 11, 1:41 PM CDTSevere Thunderstorm WarningARXJuneau, Monroe64 min
Aug 11, 1:48 PM CDTTornado WarningARXJuneau, Monroe42 min
Aug 11, 2:06 PM CDTSevere Thunderstorm WarningARXLa Crosse, Monroe39 min
Aug 11, 2:18 PM CDTSevere Thunderstorm WarningARXLa Crosse, Monroe, Vernon42 min
Aug 11, 2:20 PM CDTTornado Warning Tornado observedConsiderable damage threatARXAdams, Juneau, Monroe55 min
Aug 11, 2:32 PM CDTSevere Thunderstorm WarningARXMonroe28 min
Aug 11, 3:06 PM CDTSevere Thunderstorm WarningARXRichland, Vernon54 min
Aug 11, 4:19 PM CDTSpecial Weather StatementARXGrant26 min
Aug 11, 4:23 PM CDTSevere Thunderstorm WarningARXGrant22 min

Nearby

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