Alert archive / Wisconsin / Tornado Warnings in 2021

Tornado Warning 11, NWS Milwaukee, WI

August 9, 2021Rock County, Walworth County, Wisconsin

NWS Milwaukee, WI issued this tornado warning at Aug 9, 2021, 3:08 PM CDT for Rock County, Walworth County, Wisconsin. It was in force for 37 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 9, 2021, 3:08 PM CDT (20:08 UTC)
Expired: Aug 9, 2021, 3:45 PM CDT
In force: 37 min
Issued by: NWS Milwaukee, WI
Area: Storm-based polygon
Tornado: Observed
Hail: 0.0 in

Counties Rock County, WI, Walworth County, WI

The radar

The Milwaukee radar (KMKX), 48 km from the middle of the area, began a volume at 20:12 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 nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 8.1 hours before the alert went out and 176 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: 1676 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 705 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 208 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.7

Open this sounding in Storm Lab

The text

As transmitted.

659 
WFUS53 KMKX 092008
TORMKX
WIC105-127-092045-
/O.NEW.KMKX.TO.W.0011.210809T2008Z-210809T2045Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Milwaukee/Sullivan WI
308 PM CDT Mon Aug 9 2021

The National Weather Service in Milwaukee/Sullivan has issued a

* Tornado Warning for...
  Southwestern Walworth County in southeastern Wisconsin...
  Southeastern Rock County in south central Wisconsin...

* Until 345 PM CDT.

* At 307 PM CDT, a confirmed tornado was located over Clinton, or 10
  miles west of Delavan, moving east at 20 mph.

  HAZARD...Damaging tornado.

  SOURCE...Public confirmed tornado near Clinton.

  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.

* Locations impacted include...
  Clinton, Darien and Allens Grove. 

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.

&&

LAT...LON 4253 8887 4262 8890 4267 8871 4254 8868
TIME...MOT...LOC 2007Z 252DEG 17KT 4258 8882 

TORNADO...OBSERVED
MAX HAIL SIZE...0.00 IN

$$

HANSEN

2 follow-up statements

215 
WWUS53 KMKX 092017
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
317 PM CDT Mon Aug 9 2021

WIC105-127-092045-
/O.CON.KMKX.TO.W.0011.000000T0000Z-210809T2045Z/
Walworth WI-Rock WI-
317 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 345 PM CDT FOR
SOUTHWESTERN WALWORTH AND EAST CENTRAL ROCK COUNTIES...
    
At 316 PM CDT, a confirmed tornado was located over Darien, or 7
miles west of Delavan, moving east at 20 mph.

HAZARD...Damaging tornado.

SOURCE...Law enforcement confirmed tornado near Carver Rock Rd and 
         Creek Rd northeast of Clinton.

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.

Locations impacted include...
Darien and Allens Grove. 

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.

&&

LAT...LON 4254 8880 4263 8884 4267 8871 4254 8868
TIME...MOT...LOC 2016Z 252DEG 17KT 4259 8876 

TORNADO...OBSERVED
MAX HAIL SIZE...0.00 IN

$$

HANSEN

393 
WWUS53 KMKX 092032
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
332 PM CDT Mon Aug 9 2021

WIC105-092042-
/O.CAN.KMKX.TO.W.0011.000000T0000Z-210809T2045Z/
Rock WI-
332 PM CDT Mon Aug 9 2021

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

LAT...LON 4260 8873 4265 8876 4267 8871 4261 8870
TIME...MOT...LOC 2032Z 236DEG 16KT 4265 8871 

$$

WIC127-092045-
/O.CON.KMKX.TO.W.0011.000000T0000Z-210809T2045Z/
Walworth WI-
332 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 345 PM CDT FOR WESTERN
WALWORTH COUNTY...
    
At 332 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Darien, or near Delavan, moving northeast at 20 mph.

HAZARD...Tornado.

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.

Locations impacted include...
Darien.

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 4260 8873 4265 8876 4267 8871 4261 8870
TIME...MOT...LOC 2032Z 236DEG 16KT 4265 8871 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

$$

HANSEN

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 7:22 AM CDT	Special Weather Statement	MKX	Green	38 min
Aug 9, 1:21 PM CDT	Heat Advisory	MKX	Columbia, Dane, Dodge, Green, Iowa, Jefferson and 9 more	30 hr
Aug 9, 3:27 PM CDT	Tornado Warning	MKX	Walworth	29 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.