Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 71, NWS Milwaukee, WI

September 7, 20214 counties in Wisconsin

NWS Milwaukee, WI issued this severe thunderstorm warning at Sep 7, 2021, 11:27 AM CDT for 4 counties in Wisconsin. It was in force for 48 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, 11:27 AM CDT (16:27 UTC)
Expired
Sep 7, 2021, 12:15 PM CDT
In force
48 min
Issued by
NWS Milwaukee, WI
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Milwaukee County, WI, Ozaukee County, WI, Washington County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 43 km from the middle of the area, began a volume at 16:29 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, 4.5 hours before the alert went out and 148 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°0°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.

599 
WUUS53 KMKX 071627
SVRMKX
WIC079-089-131-133-071715-
/O.NEW.KMKX.SV.W.0071.210907T1627Z-210907T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Milwaukee/Sullivan WI
1127 AM CDT Tue Sep 7 2021

The National Weather Service in Milwaukee/Sullivan has issued a

* Severe Thunderstorm Warning for...
  Southern Ozaukee County in southeastern Wisconsin... 
  Northern Milwaukee County in southeastern Wisconsin... 
  Northern Waukesha County in southeastern Wisconsin... 
  Southern Washington County in southeastern Wisconsin...

* Until 1215 PM CDT.

* At 1126 AM CDT, severe thunderstorms were located along a line 
  extending from near Hustisford to Johnson Creek, moving east at 55 
  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.

* Severe thunderstorms will be near...
  Hartford, Oconomowoc and Lac La Belle around 1135 AM CDT.
  Delafield and Okauchee Lake around 1140 AM CDT.
  Hartland and Merton around 1145 AM CDT.
  Waukesha, Pewaukee, Sussex, Jackson, Germantown and Lisbon around 
  1150 AM CDT.
  Brookfield, Cedarburg, Elm Grove, Thiensville, Butler and 
  Brookfield around 1155 AM CDT.
  Wauwatosa, Mequon, Grafton and Bayside around 1200 PM CDT.
  Whitefish Bay and Glendale around 1205 PM CDT.

Other locations impacted by these severe thunderstorms include
Marquette University, Colgate, Chenequa, Richfield, UW-
Milwaukee, Mapleton, Stone Bank, Summit, North Lake and Holy Hill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4303 8790 4304 8854 4320 8854 4320 8842
      4332 8842 4331 8789 4324 8791 4318 8788
      4312 8790 4310 8787 4307 8787
TIME...MOT...LOC 1626Z 272DEG 59KT 4334 8867 4307 8876 

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

$$

GEHRING
1 follow-up statement
424 
WWUS53 KMKX 071654
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
1154 AM CDT Tue Sep 7 2021

WIC079-089-131-133-071715-
/O.CON.KMKX.SV.W.0071.000000T0000Z-210907T1715Z/
Ozaukee WI-Milwaukee WI-Waukesha WI-Washington WI-
1154 AM CDT Tue Sep 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1215 PM CDT
FOR SOUTHWESTERN OZAUKEE...NORTHERN MILWAUKEE...NORTHERN WAUKESHA AND
SOUTHEASTERN WASHINGTON COUNTIES...

At 1154 AM CDT, severe thunderstorms were located along a line
extending from near Cedarburg to Brookfield, moving east at 55 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...
  Whitefish Bay and Glendale around 1205 PM CDT.

Other locations impacted by these severe thunderstorms include
Marquette University, Colgate, Chenequa, Richfield, UW-
Milwaukee, Stone Bank, Summit, North Lake, Kirchhayn and Oconomowoc
Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4303 8790 4304 8854 4315 8848 4318 8833
      4331 8818 4331 8789 4324 8791 4318 8788
      4312 8790 4310 8787 4307 8787
TIME...MOT...LOC 1654Z 272DEG 57KT 4332 8802 4305 8812 

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

$$

GEHRING

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, 11:31 AM CDTSpecial Marine WarningMKX89 min
Sep 7, 11:42 AM CDTSevere Thunderstorm WarningMKXRock, Walworth48 min
Sep 7, 11:45 AM CDTSevere Thunderstorm WarningMKXJefferson, Milwaukee, Waukesha60 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.