Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 80, NWS Milwaukee, WI

September 13, 2021Jefferson County, Waukesha County, Wisconsin

NWS Milwaukee, WI issued this severe thunderstorm warning at Sep 13, 2021, 2:38 AM CDT for Jefferson County, Waukesha County, Wisconsin. It was in force for 52 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 13, 2021, 2:38 AM CDT (07:38 UTC)
Expired
Sep 13, 2021, 3:30 AM CDT
In force
52 min
Issued by
NWS Milwaukee, WI
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Jefferson County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 15 km from the middle of the area, began a volume at 07:38 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

Green Bay/Straub, WI (KGRB), launched 00:00Z, 7.6 hours before the alert went out and 161 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 00:00Z on 2021-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2021-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -16 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1081 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
-16 m²/s²
0-3 km storm-relative helicity
105 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

929 
WUUS53 KMKX 130738
SVRMKX
WIC055-133-130830-
/O.NEW.KMKX.SV.W.0080.210913T0738Z-210913T0830Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Milwaukee/Sullivan WI
238 AM CDT Mon Sep 13 2021

The National Weather Service in Milwaukee/Sullivan has issued a

* Severe Thunderstorm Warning for...
  Northwestern Waukesha County in southeastern Wisconsin...
  Northeastern Jefferson County in southeastern Wisconsin...

* Until 330 AM CDT.

* At 237 AM CDT, a severe thunderstorm was located over Lake Mills,
  moving east at 35 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Watertown, Hartland, Jefferson, Delafield, Wales, Okauchee Lake,
  Oconomowoc, Ottawa, Johnson Creek, Dousman, Lac La Belle, Ixonia,
  Rome, Nashotah, Milford, Waterville, Sullivan, Oconomowoc Lake,
  Chenequa and Mapleton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4298 8887 4318 8886 4320 8858 4319 8836
      4297 8834
TIME...MOT...LOC 0737Z 264DEG 29KT 4305 8887 

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

$$

BOXELL
1 follow-up statement
179 
WWUS53 KMKX 130812
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
312 AM CDT Mon Sep 13 2021

WIC055-130821-
/O.CAN.KMKX.SV.W.0080.000000T0000Z-210913T0830Z/
Jefferson WI-
312 AM CDT Mon Sep 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN JEFFERSON COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4297 8854 4314 8854 4313 8835 4297 8834
TIME...MOT...LOC 0811Z 270DEG 28KT 4303 8852 

$$

WIC133-130830-
/O.CON.KMKX.SV.W.0080.000000T0000Z-210913T0830Z/
Waukesha WI-
312 AM CDT Mon Sep 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 AM CDT
FOR NORTHWESTERN WAUKESHA COUNTY...

At 311 AM CDT, a severe thunderstorm was located over Dousman, or 7
miles southwest of Delafield, moving east at 30 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
Hartland, Delafield, Wales, Okauchee Lake, Oconomowoc, Ottawa,
Dousman, Lac La Belle, Nashotah, Waterville, Oconomowoc Lake,
Chenequa, Summit and Lapham Peak St Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4297 8854 4314 8854 4313 8835 4297 8834
TIME...MOT...LOC 0811Z 270DEG 28KT 4303 8852 

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

$$

BOXELL

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 13, 1:41 AM CDTSpecial Weather StatementMKXDane, Iowa34 min
Sep 13, 1:55 AM CDTSevere Thunderstorm WarningMKXDane, Jefferson50 min
Sep 13, 2:15 AM CDTSevere Thunderstorm WarningMKXDane, Iowa45 min
Sep 13, 2:45 AM CDTSevere Thunderstorm WarningMKXDane30 min
Sep 13, 3:15 AM CDTSpecial Weather StatementMKXJefferson30 min
Sep 13, 3:29 AM CDTSpecial Weather StatementMKXWaukesha31 min
Sep 13, 3:34 AM CDTSevere Thunderstorm WarningMKXMilwaukee, Waukesha41 min
Sep 13, 3:38 AM CDTSpecial Marine WarningMKX75 min
Sep 13, 6:11 AM CDTSevere Thunderstorm WarningMKXIowa, Sauk28 min
Sep 13, 7:43 AM CDTSpecial Weather StatementMKXJefferson32 min
Sep 13, 8:21 AM CDTSpecial Weather StatementMKXMilwaukee, Ozaukee, Washington, Waukesha39 min
Sep 13, 1:13 PM CDTSmall Craft AdvisoryMKX29 hr
Sep 13, 3:51 PM CDTSpecial Weather StatementMKXDodge39 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.