Alert archive / Wisconsin / Tornado Warnings in 2020

Tornado Warning 1, NWS Green Bay, WI

June 20, 2020Winnebago County, Wisconsin

NWS Green Bay, WI issued this tornado warning at Jun 20, 2020, 5:07 PM CDT for Winnebago County, Wisconsin. It was in force for 9 min. 3 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
Jun 20, 2020, 5:07 PM CDT (22:07 UTC)
Expired
Jun 20, 2020, 5:16 PM CDT
In force
9 min
Issued by
NWS Green Bay, WI
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Winnebago County, WI

The radar

The Green Bay radar (KGRB), 53 km from the middle of the area, began a volume at 22:11 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.

What was reported inside it

TimeReportWhereRemark
Jun 20, 5:09 PM CDTFUNNEL CLOUD2 W Allenville, WIFUNNEL DROPPED OUT OF WALL CLOUD, WAS PRESENT BRIEFLY, THEN WENT BACK TO THE WALL CLOUD. WAS NOT ABLE TO CONFIRM CONTACT WITH GROUND OR NOT
Jun 20, 5:09 PM CDTFUNNEL CLOUD2 W Allenville, WIFUNNEL DROPPED OUT OF WALL CLOUD, WAS PRESENT BRIEFLY, THEN WENT BACK TO THE WALL CLOUD. WAS NOT ABLE TO CONFIRM CONTACT WITH GROUND OR NOT.
Jun 20, 5:26 PM CDTTORNADO1 E Butte Des Morts, WISTORM CHASER PROVIDED PICTURE OF TORNADO TOUCHDOWN ON COUNTY ROAD S NEAR LAKE BUTTE DES MORTS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 10.1 hours before the alert went out and 52 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 2020-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 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 2020-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 140 square meters per square second.193958Sfc1 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
103 J/kg
Mixed-layer CIN
-56 J/kg
Mixed-layer LCL
1063 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
140 m²/s²
0-3 km storm-relative helicity
144 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

253 
WFUS53 KGRB 202207
TORGRB
WIC139-202230-
/O.NEW.KGRB.TO.W.0001.200620T2207Z-200620T2230Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Green Bay WI
507 PM CDT Sat Jun 20 2020

The National Weather Service in Green Bay has issued a

* Tornado Warning for...
  Northern Winnebago County in east central Wisconsin...

* Until 530 PM CDT.
    
* At 506 PM CDT, a severe thunderstorm capable of producing a 
  tornado was located 8 miles northwest of Oshkosh, 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.

* This dangerous storm will be near...
  Menasha around 530 PM CDT.

Other locations impacted by this tornadic thunderstorm include Butte
Des Morts, Highland Shore, Larsen, Lake Butte Des Morts, Uw Fox
Valley, Rivermoor, Winneconne, Clarks Point, Allenville and Lake
Butte Des Mor.

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 4414 8879 4424 8869 4425 8841 4424 8840
      4412 8841 4401 8861
TIME...MOT...LOC 2206Z 224DEG 13KT 4413 8863 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

RDM
1 follow-up statement
125 
WWUS53 KGRB 202216
SVSGRB

Severe Weather Statement
National Weather Service Green Bay WI
516 PM CDT Sat Jun 20 2020

WIC139-202226-
/O.CAN.KGRB.TO.W.0001.000000T0000Z-200620T2230Z/
Winnebago WI-
516 PM CDT Sat Jun 20 2020

...THE TORNADO WARNING FOR NORTHERN WINNEBAGO COUNTY IS CANCELLED...
    
The tornado threat has diminished for the immediate future and the 
Tornado Warning has been cancelled. However, damaging winds remain 
likely and a Severe Thunderstorm Warning remains in effect for the 
area.

LAT...LON 4414 8879 4424 8869 4425 8841 4424 8840
      4412 8841 4401 8861
TIME...MOT...LOC 2215Z 224DEG 13KT 4416 8859 

$$

RDM

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 8:41 AM CDTSpecial Weather StatementGRBPortage49 min
Jun 20, 9:21 AM CDTAreal Flood AdvisoryGRBLanglade, Marathon, Portage, Shawano, Wood4 hr
Jun 20, 9:25 AM CDTSpecial Weather StatementGRBPortage50 min
Jun 20, 10:41 AM CDTAreal Flood AdvisoryGRBFlorence, Forest, Langlade, Lincoln, Oneida, Shawano5 hr
Jun 20, 10:52 AM CDTSpecial Weather StatementGRBPortage38 min
Jun 20, 2:12 PM CDTSpecial Weather StatementGRBKewaunee, Manitowoc33 min
Jun 20, 3:29 PM CDTSpecial Weather StatementGRBOutagamie, Waupaca46 min
Jun 20, 4:15 PM CDTSpecial Weather StatementGRBOutagamie, Shawano, Waupaca45 min
Jun 20, 4:29 PM CDTSpecial Weather StatementGRBWinnebago46 min
Jun 20, 4:44 PM CDTSevere Thunderstorm WarningGRBWinnebago35 min
Jun 20, 5:18 PM CDTSpecial Weather StatementGRBOutagamie42 min
Jun 20, 5:33 PM CDTSpecial Weather StatementGRBWinnebago27 min
Jun 20, 5:49 PM CDTSevere Thunderstorm WarningGRBCalumet, Winnebago26 min
Jun 20, 6:37 PM CDTSpecial Weather StatementGRBBrown38 min

Nearby

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