Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 73, NWS Milwaukee, WI

September 7, 2021Jefferson County, Milwaukee County, Waukesha County, Wisconsin

NWS Milwaukee, WI issued this severe thunderstorm warning at Sep 7, 2021, 11:45 AM CDT for Jefferson County, Milwaukee County, Waukesha County, Wisconsin. It was in force for 60 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 7, 2021, 11:45 AM CDT (16:45 UTC)
Expired
Sep 7, 2021, 12:45 PM CDT
In force
60 min
Issued by
NWS Milwaukee, WI
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Jefferson County, WI, Milwaukee County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 43 km from the middle of the area, began a volume at 16:48 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
Sep 7, 11:21 AM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 4.8 hours before the alert went out and 173 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 2021-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 14 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 2021-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -120 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
14 J/kg
Mixed-layer CIN
-216 J/kg
Mixed-layer LCL
1012 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-120 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.1

Open this sounding in Storm Lab

The text

As transmitted.

095 
WUUS53 KMKX 071645
SVRMKX
WIC055-079-133-071745-
/O.NEW.KMKX.SV.W.0073.210907T1645Z-210907T1745Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Milwaukee/Sullivan WI
1145 AM CDT Tue Sep 7 2021

The National Weather Service in Milwaukee/Sullivan has issued a

* Severe Thunderstorm Warning for...
  Southern Milwaukee County in southeastern Wisconsin...
  Southern Waukesha County in southeastern Wisconsin...
  Southeastern Jefferson County in southeastern Wisconsin...

* Until 1245 PM CDT.

* At 1145 AM CDT, severe thunderstorms were located along a line
  extending from near Okauchee Lake to near Lake Koshkonong, moving
  east at 55 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Severe thunderstorms will be near...
  Delafield and Wales around 1150 AM CDT.
  Waukesha and Pewaukee around 1155 AM CDT.
  New Berlin, Brookfield, Palmyra and Brookfield around 1200 PM CDT.
  Milwaukee, Wauwatosa and Elm Grove around 1205 PM CDT.
  West Milwaukee, Ottawa and North Prairie around 1210 PM CDT.
  Mukwonago and Milwaukee Hoan Bridge around 1215 PM CDT.
  Vernon around 1220 PM CDT.
  Big Bend around 1225 PM CDT.

Other locations impacted by these severe thunderstorms include State
Fair Park, Waterville, Marquette University, Mitchell Park Domes,
Milwaukee Co Zoo, Miller Park, Genesee Depot, Genesee, Milwaukee
South Shore Park and Maier Festival Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4284 8784 4285 8873 4305 8856 4304 8789
      4301 8789 4296 8785 4288 8785 4285 8782
TIME...MOT...LOC 1645Z 267DEG 48KT 4310 8841 4285 8888 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

GEHRING
2 follow-up statements
449 
WWUS53 KMKX 071703
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
1203 PM CDT Tue Sep 7 2021

WIC055-079-133-071745-
/O.CON.KMKX.SV.W.0073.000000T0000Z-210907T1745Z/
Milwaukee WI-Waukesha WI-Jefferson WI-
1203 PM CDT Tue Sep 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 PM CDT
FOR SOUTHERN MILWAUKEE...SOUTHERN WAUKESHA AND SOUTHEASTERN JEFFERSON
COUNTIES...

At 1202 PM CDT, severe thunderstorms were located along a line
extending from near Butler to Palmyra, moving east at 55 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

These severe storms will be near...
  Milwaukee, Wauwatosa, Brookfield, Elm Grove and West Milwaukee 
  around 1210 PM CDT.
  Milwaukee Hoan Bridge around 1215 PM CDT.
  Vernon around 1220 PM CDT.
  Big Bend around 1225 PM CDT.
  West Allis and Muskego around 1230 PM CDT.
  Greenfield, Greendale and Hales Corners around 1235 PM CDT.
  Oak Creek, St. Francis and Franklin around 1240 PM CDT.
  South Milwaukee and Cudahy around 1245 PM CDT.

Other locations impacted by these severe thunderstorms include State
Fair Park, Waterville, Marquette University, Mitchell Park Domes,
Milwaukee Co Zoo, Miller Park, Genesee Depot, Genesee, Milwaukee
South Shore Park and Maier Festival Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4284 8784 4285 8873 4305 8856 4304 8789
      4301 8789 4296 8785 4288 8785 4285 8782
TIME...MOT...LOC 1702Z 267DEG 48KT 4311 8812 4286 8859 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

GEHRING
671 
WWUS53 KMKX 071723
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
1223 PM CDT Tue Sep 7 2021

WIC055-079-133-071745-
/O.CON.KMKX.SV.W.0073.000000T0000Z-210907T1745Z/
Milwaukee WI-Waukesha WI-Jefferson WI-
1223 PM CDT Tue Sep 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 PM CDT
FOR SOUTHERN MILWAUKEE...SOUTHERN WAUKESHA AND SOUTHEASTERN JEFFERSON
COUNTIES...

At 1223 PM CDT, severe thunderstorms were located along a line
extending from Milwaukee to near Waterford North, moving east at 60
mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

These severe storms will be near...
  South Milwaukee, Cudahy, St. Francis and Milwaukee Hoan Bridge 
  around 1230 PM CDT.

Other locations impacted by these severe thunderstorms include State
Fair Park, Waterville, Marquette University, Mitchell Park Domes,
Milwaukee Co Zoo, Miller Park, Genesee Depot, Genesee, Milwaukee
South Shore Park and Maier Festival Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

LAT...LON 4285 8865 4305 8848 4304 8789 4301 8789
      4296 8785 4288 8785 4285 8782 4284 8784
TIME...MOT...LOC 1723Z 276DEG 51KT 4303 8793 4280 8826 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

WOOD

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 6, 9:06 PM CDTSmall Craft AdvisoryMKX45 hr
Sep 7, 2:21 AM CDTGale WarningMKX13 hr
Sep 7, 8:41 AM CDTSpecial Weather StatementMKXMarquette49 min
Sep 7, 8:57 AM CDTSevere Thunderstorm WarningMKXGreen Lake, Marquette48 min
Sep 7, 9:34 AM CDTSevere Thunderstorm WarningMKXFond du Lac56 min
Sep 7, 10:10 AM CDTSevere Thunderstorm WarningMKXFond du Lac50 min
Sep 7, 10:27 AM CDTSevere Thunderstorm WarningMKXFond du Lac, Sheboygan78 min
Sep 7, 10:40 AM CDTSpecial Weather StatementMKXColumbia, Dane, Dodge, Iowa65 min
Sep 7, 10:57 AM CDTSpecial Marine WarningMKX63 min
Sep 7, 11:01 AM CDTSevere Thunderstorm WarningMKXColumbia, Dane, Dodge, Jefferson59 min
Sep 7, 11:04 AM CDTSevere Thunderstorm WarningMKXDodge, Fond du Lac, Ozaukee, Sheboygan, Washington56 min
Sep 7, 11:11 AM CDTSevere Thunderstorm WarningMKXGreen, Rock34 min
Sep 7, 11:22 AM CDTSpecial Marine WarningMKX53 min
Sep 7, 11:27 AM CDTSevere Thunderstorm WarningMKXMilwaukee, Ozaukee, Washington, Waukesha48 min
Sep 7, 11:31 AM CDTSpecial Marine WarningMKX89 min
Sep 7, 11:42 AM CDTSevere Thunderstorm WarningMKXRock, Walworth48 min
Sep 7, 12:18 PM CDTSpecial Marine WarningMKX87 min
Sep 7, 12:19 PM CDTSevere Thunderstorm WarningMKXRacine, Walworth40 min
Sep 7, 12:30 PM CDTSevere Thunderstorm WarningMKXKenosha, Racine, Rock, Walworth60 min
Sep 7, 12:47 PM CDTSpecial Weather StatementMKXMilwaukee28 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 2021Every severe thunderstorm warning 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.