Alert archive / Wisconsin / Tornado Warnings in 2020

Tornado Warning 8, NWS La Crosse, WI

August 10, 2020Grant County, Wisconsin

NWS La Crosse, WI issued this tornado warning at Aug 10, 2020, 1:15 PM CDT for Grant County, Wisconsin. It was in force for 15 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: Aug 10, 2020, 1:15 PM CDT (18:15 UTC)
Expired: Aug 10, 2020, 1:30 PM CDT
In force: 15 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.0 in

County Grant County, WI

The radar

The Quad Cities radar (KDVN), 125 km from the middle of the area, began a volume at 18:17 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 10, 1:15 PM CDT	TSTM WND DMG	Platteville, WI	4 ROADS BLOCKED OFF IN THE TOWN AND 8-10 INCH TREES AND TREE LIMBS DOWN.
Aug 10, 1:20 PM CDT	TSTM WND DMG	1 W Platteville, WI	TREE DAMAGE AND POWER OUTAGES.

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 10, 11:26 AM CDT	Severe Thunderstorm Watch PDS	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 6.3 hours before the alert went out and 123 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: 1683 J/kg
Mixed-layer CIN: -223 J/kg
Mixed-layer LCL: 894 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 80 m²/s²
0-3 km storm-relative helicity: 96 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

951 
WFUS53 KARX 101815
TORARX
WIC043-101830-
/O.NEW.KARX.TO.W.0008.200810T1815Z-200810T1830Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service La Crosse WI
115 PM CDT Mon Aug 10 2020

The National Weather Service in La Crosse has issued a

* Tornado Warning for...
  East central Grant County in southwestern Wisconsin...

* Until 130 PM CDT.
    
* At 115 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Platteville, moving southeast at 25 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
  east central Grant County, including the following locations...
  Platteville Airport.

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 4271 9055 4278 9051 4277 9043 4275 9042
      4266 9043
TIME...MOT...LOC 1815Z 295DEG 22KT 4273 9046 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

NMB

1 follow-up statement

678 
WWUS53 KARX 101827
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
127 PM CDT Mon Aug 10 2020

WIC043-101836-
/O.EXP.KARX.TO.W.0008.000000T0000Z-200810T1830Z/
Grant WI-
127 PM CDT Mon Aug 10 2020

...THE TORNADO WARNING FOR EAST CENTRAL GRANT COUNTY WILL EXPIRE AT
130 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.  However gusty winds are still possible with
this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
southwestern Wisconsin.

LAT...LON 4271 9055 4278 9051 4277 9043 4275 9042
      4266 9043
TIME...MOT...LOC 1826Z 293DEG 20KT 4271 9040 

$$

NMB

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 5:21 AM CDT	Severe Thunderstorm Warning	ARX	Buffalo	73 min
Aug 10, 6:20 AM CDT	Severe Thunderstorm Warning	ARX	Jackson, La Crosse, Trempealeau	55 min
Aug 10, 6:51 AM CDT	Severe Thunderstorm Warning	ARX	Jackson, Monroe	54 min
Aug 10, 7:20 AM CDT	Severe Thunderstorm Warning	ARX	Adams, Juneau	70 min
Aug 10, 11:44 AM CDT	Special Weather Statement	ARX	Crawford, Grant	46 min
Aug 10, 12:04 PM CDT	Severe Thunderstorm Warning	ARX	Crawford, Grant, Richland	41 min
Aug 10, 12:37 PM CDT	Severe Thunderstorm Warning	ARX	Grant	38 min

Nearby

Tornado Warnings in Wisconsin, 2020 Every tornado warning in 2020 Tornadoes in 2020

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.