Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 42, NWS Milwaukee, WI

August 10, 20214 counties in Wisconsin

NWS Milwaukee, WI issued this severe thunderstorm warning at Aug 10, 2021, 4:02 PM CDT for 4 counties in Wisconsin. It was in force for 73 min. 7 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, 2021, 4:02 PM CDT (21:02 UTC)
Expired: Aug 10, 2021, 5:15 PM CDT
In force: 73 min
Issued by: NWS Milwaukee, WI
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Dane County, WI, Iowa County, WI, Lafayette County, WI, Sauk County, WI

The radar

The La Crosse radar (KARX), 111 km from the middle of the area, began a volume at 21:06 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, 4:37 PM CDT	TSTM WND DMG	Rewey, WI	IOWA CO. DISPATCH RELAYS REPORT OF A TREE DOWN ON HUGHIT STREET. TIME ESTIMATED FROM RADAR.
Aug 10, 4:39 PM CDT	TSTM WND DMG	Belmont, WI	LAFAYETTE CO DISPATCH RELAYS REPORT OF DAMAGE TO HOME CAUSED BY A FALLING TREE. TIME ESTIMATED FROM RADAR.
Aug 10, 4:47 PM CDT	TSTM WND DMG	1 Sse Mineral Point, WI	IOWA CO DISPATCH RELAYS REPORT OF A TREE DOWN ON STATE STREET. TIME ESTIMATED FROM RADAR.
Aug 10, 5:00 PM CDT	TSTM WND GST 49	6 Wnw Spring Green, WI	LNR - LONE ROCK.
Aug 10, 5:05 PM CDT	TSTM WND DMG	Spring Green, WI	POWER POLES SNAPPED.
Aug 10, 5:05 PM CDT	TSTM WND DMG	Spring Green, WI	SMALL TREE BRANCHES DOWN.
Aug 10, 5:25 PM CDT	TSTM WND DMG	Black Earth, WI	TREES AND WIRES DOWN.

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, 3:47 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 9.0 hours before the alert went out and 194 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: 32 J/kg
Mixed-layer CIN: -550 J/kg
Mixed-layer LCL: 828 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

253 
WUUS53 KMKX 102102
SVRMKX
WIC025-049-065-111-102215-
/O.NEW.KMKX.SV.W.0042.210810T2102Z-210810T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Milwaukee/Sullivan WI
402 PM CDT Tue Aug 10 2021

The National Weather Service in Milwaukee/Sullivan has issued a

* Severe Thunderstorm Warning for...
  Northwestern Lafayette County in south central Wisconsin...
  Iowa County in south central Wisconsin...
  Northwestern Dane County in south central Wisconsin...
  Sauk County in south central Wisconsin...

* Until 515 PM CDT.

* At 401 PM CDT, severe thunderstorms were located along a line
  extending from Hillsboro to 6 miles north of Belmont, moving
  northeast at 40 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.

* Locations impacted include...
  Baraboo, Reedsburg, Dodgeville, Prairie Du Sac, Sauk City,
  Wisconsin Dells, Mineral Point, Lake Delton, Mazomanie, Spring
  Green, West Baraboo, Black Earth, Belmont, Benton, Barneveld,
  Highland, Arena, Plain, Bluffview and North Freedom.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with these storms. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

&&

LAT...LON 4320 9043 4321 9029 4317 9019 4355 9019
      4356 9031 4364 9031 4364 8979 4360 8976
      4360 8972 4357 8973 4356 8960 4338 8960
      4336 8965 4336 8967 4330 8973 4329 8957
      4251 9042
TIME...MOT...LOC 2101Z 222DEG 36KT 4365 9037 4283 9035 

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

$$

KAVINSKY

2 follow-up statements

753 
WWUS53 KMKX 102122
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
422 PM CDT Tue Aug 10 2021

WIC025-049-065-111-102215-
/O.CON.KMKX.SV.W.0042.000000T0000Z-210810T2215Z/
Lafayette WI-Iowa WI-Dane WI-Sauk WI-
422 PM CDT Tue Aug 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR NORTHWESTERN LAFAYETTE...IOWA...NORTHWESTERN DANE AND SAUK
COUNTIES...

At 421 PM CDT, severe thunderstorms were located along a line
extending from near Mauston to near Spring Green to near Cuba City,
moving northeast at 45 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Baraboo, Reedsburg, Dodgeville, Prairie Du Sac, Sauk City, Wisconsin
Dells, Mineral Point, Lake Delton, Mazomanie, Spring Green, West
Baraboo, Black Earth, Belmont, Benton, Barneveld, Highland, Arena,
Plain, Bluffview and North Freedom.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4320 9043 4321 9029 4317 9019 4355 9019
      4356 9031 4364 9031 4364 8979 4360 8976
      4360 8972 4357 8973 4356 8960 4338 8960
      4336 8965 4336 8967 4330 8973 4329 8957
      4251 9042
TIME...MOT...LOC 2121Z 239DEG 37KT 4374 9006 4321 8997 4257 9045 

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

$$

KAVINSKY

067 
WWUS53 KMKX 102136
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
436 PM CDT Tue Aug 10 2021

WIC025-049-065-111-102215-
/O.CON.KMKX.SV.W.0042.000000T0000Z-210810T2215Z/
Lafayette WI-Iowa WI-Dane WI-Sauk WI-
436 PM CDT Tue Aug 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR NORTHWESTERN LAFAYETTE...IOWA...NORTHWESTERN DANE AND SAUK
COUNTIES...

At 435 PM CDT, severe thunderstorms were located along a line
extending from 8 miles east of Mauston to near Sauk City to near
Shullsburg, moving east at 40 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Weather equipment in Platteville reported a 70 mph wind 
         gust. 

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Baraboo, Reedsburg, Dodgeville, Prairie Du Sac, Sauk City, Wisconsin
Dells, Mineral Point, Lake Delton, Mazomanie, Spring Green, West
Baraboo, Black Earth, Belmont, Benton, Barneveld, Highland, Arena,
Plain, Bluffview and North Freedom.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4320 9043 4321 9029 4317 9019 4355 9019
      4356 9031 4364 9031 4364 8979 4360 8976
      4360 8972 4357 8973 4356 8960 4338 8960
      4336 8965 4336 8967 4330 8973 4329 8957
      4251 9042
TIME...MOT...LOC 2135Z 270DEG 36KT 4381 8991 4328 8982 4264 9030 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH

$$

KAVINSKY

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 7:13 PM CDT	Marine Dense Fog Advisory	MKX		14 hr
Aug 10, 2:16 PM CDT	Heat Advisory	MKX	Dane, Dodge, Green, Iowa, Jefferson, Kenosha and 8 more	29 hr
Aug 10, 4:25 PM CDT	Severe Thunderstorm Warning	MKX	Iowa, Lafayette	80 min
Aug 10, 5:08 PM CDT	Severe Thunderstorm Warning	MKX	Columbia, Dane, Green, Iowa, Sauk	67 min
Aug 10, 5:36 PM CDT	Special Weather Statement	MKX	Rock	39 min
Aug 10, 5:42 PM CDT	Severe Thunderstorm Warning	MKX	Dane, Dodge, Jefferson, Rock	78 min
Aug 10, 6:08 PM CDT	Severe Thunderstorm Warning	MKX	Dodge, Jefferson, Kenosha, Racine, Walworth, Washington and 1 more	97 min
Aug 10, 6:12 PM CDT	Severe Thunderstorm Warning	MKX	Columbia, Dane	20 min
Aug 10, 6:24 PM CDT	Special Marine Warning	MKX		111 min
Aug 10, 6:44 PM CDT	Special Weather Statement	MKX	Fond du Lac, Sheboygan	76 min
Aug 10, 6:51 PM CDT	Severe Thunderstorm Warning	MKX	Kenosha, Milwaukee, Ozaukee, Racine	54 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.