Strong to severe thunderstorms developed across much of south central and southeast Wisconsin during the evening of June 21, 2010.  A vigorous upper level disturbance helped to support deep vertical motions in the atmosphere, along with strong deep layer wind shear.  This lift acted on a warm and very moist atmosphere, carried into the region on a 40 to 50 knot low-level jet.  The result was powerful rotating thunderstorms, with damaging straight line winds, large hail, and in this case, 5 tornadoes.  At one point during the height of the event, around 48,000 customers in southeast Wisconsin were without electric power due to downed power lines.  However, power-line and power-pole loss estimates were not available and do not show up as damage amounts in any individual event within this severe weather episode.

Hail in JEFFERSON, WISCONSIN
From 21-JUN-10 19:22:00 to 21-JUN-10 19:22:00 (CST-6)
Location: FT ATKINSON
Magnitude: 1.50 
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Public

The public reported large hail from a severe thunderstorm that caused damage to the roofs of several homes.

Hail in WAUKESHA, WISCONSIN
From 21-JUN-10 20:00:00 to 21-JUN-10 20:05:00 (CST-6)
Location: EAGLE
Magnitude: 1.50 
Reported by: Trained Spotter

Thunderstorm Wind in WALWORTH, WISCONSIN
From 21-JUN-10 20:34:00 to 21-JUN-10 20:34:00 (CST-6)
Location: EAST TROY
Magnitude: 65.00 EG
Reported by: Law Enforcement

Law enforcement officials reported trees and power lines were blown down in multiple locations in East Troy due to strong thunderstorm wind gusts.

Tornado in DANE, WISCONSIN
From 21-JUN-10 18:41:00 to 21-JUN-10 18:43:00 (CST-6)
Location: CROSS PLAINS
Tornado F-scale: EF1
Property damage: 15.00K
Reported by: Law Enforcement

A brief EF1 tornado spun up within the city of Cross Plains between Julius Street and Sylvia Pine Way and moved northeast to near the intersection of Caesar Street and Woodside Drive and dissipated. At least 3 homes had minor roof damage.  A number of large trees were uprooted or broken in half.  An in-ground basketball pole was bent to a 45 degree angle.  Roof soffit and fascia siding was peeled off a municipal pool house. The severe thunderstorm become outflow dominated and resulted in straight line wind damage (trees) further northeast over rural areas northeast Cross Plains.  some crop damage was seen, but loss estimates were unavailable.  The exact start location was Lat. 43.114895 Lon. -89.647946.  The exact end location was Lat. 43.11522 Lon. -89.645138. The EF-rating was based on DI 2 (TH), DOD 4 which suggests wind speeds between 90 and 100 mph.  Average path width was 20 yards.

Tornado in WAUKESHA, WISCONSIN
From 21-JUN-10 20:36:00 to 21-JUN-10 20:48:00 (CST-6)
Location: BIG BEND
Tornado F-scale: EF1
Property damage: 430.00K
Reported by: Law Enforcement

This EF1 tornado affected the Big Bend and Muskego area, and spun up a little more than 2 miles north of Big Bend about 1/10 of a mile southeast of the intersection of Interstate 43 and STH 164.  The tornado moved east, dissipating about 1/2 mile south of Tess Corners, just northwest of the intersection of Woods Road and Durham Drive.  The roof of the Tess Corners Fire Department tore off, and the U.S. Post Office building in Muskego was damaged when an air conditioning unit was blown off the roof.  Several post office vehicles were also damaged. The building housing Muskego Beer and Liquor was badly damaged when a wall collapsed and destroyed half the building.  All together, 35 residential dwellings were minimally affected, and 41 homes sustained minor damage.  Seventeen businesses were minimally affected, and 1 sustained major damage.  Some crops were damaged, but no information on loss estimates was available.  Total estimated private sector damage was about $430,000.  Public sector structural damage totaled about $15,000.  Additionally, other public service (non-damage) costs totaled $65,000; which included $45,000 for debris clearance, $10,000 for protective measures, and $10,000 for road systems.  Hundreds of trees were uprooted or damaged.  Starting location point was Lat 42.91015 Lon -88.21483 with the ending point Lat 42.91118 Lon -88.09850. The EF-rating was based on DI 27 (TH) DOD3 which suggests a wind speed of 105 mph. The average path width was 90 yards.

Tornado in LAFAYETTE, WISCONSIN
From 21-JUN-10 18:39:00 to 21-JUN-10 18:45:00 (CST-6)
Location: GRATIOT
Tornado F-scale: EF1
Property damage: 15.00K
Reported by: Law Enforcement

An EF1 tornado developed in a rural area about 4.5 miles southeast of Darlington about 1/2 mile southwest of the intersection of Walnut Road and Pecatonica Road.  The tornado moved east-northeast for about 2.2 miles, and dissipated about 0.4 miles north of the intersection of Walnut Road and Tish Road.  Tornadic damage was sporadic in the second-half of the tornado's life.  One residence experienced siding and window damage.  An outbuilding used as a garage on a farmstead lost its metal roof.  One large hardwood tree was blown down and other tree limbs were broken.  Minor crop damage was noted, but loss estimates were not available.  The exact start location was Lat 42.63352 Lon. -90.04077.  The exact end location was Lat. 42.64554 Lon. -90.00035.  The EF-rating was based on DI 1 (SBO), DOD 5 which suggests wind speeds between 90 and 95 mph.  Average path width was 50 yards.

Thunderstorm Wind in WAUKESHA, WISCONSIN
From 21-JUN-10 20:20:00 to 21-JUN-10 20:20:00 (CST-6)
Location: DOUSMAN
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement officials reported a number of tress blown down across the town due to strong thunderstorm winds.

Thunderstorm Wind in GREEN, WISCONSIN
From 21-JUN-10 19:03:00 to 21-JUN-10 19:03:00 (CST-6)
Location: JORDAN
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement officials reported numerous trees blown down by thunderstorm wind gusts estimated at 56 knots (64 mph).

Thunderstorm Wind in WAUKESHA, WISCONSIN
From 21-JUN-10 20:48:00 to 21-JUN-10 20:48:00 (CST-6)
Location: MUSKEGO
Magnitude: 65.00 EG
Reported by: Law Enforcement

Law enforcement officials reported numerous trees and power lines blown down across the northern quarter of the community.

Thunderstorm Wind in RACINE, WISCONSIN
From 21-JUN-10 20:43:00 to 21-JUN-10 20:43:00 (CST-6)
Location: WIND LAKE
Magnitude: 60.00 EG
Reported by: Law Enforcement

Police officials reported many trees and power lines down in Wind Lake.

Thunderstorm Wind in RACINE, WISCONSIN
From 21-JUN-10 21:08:00 to 21-JUN-10 21:08:00 (CST-6)
Location: STURTEVANT
Magnitude: 52.00 EG
Reported by: Amateur Radio

HAM radio operator estimated 52 knot (60 mph) thunderstorm wind gusts in Sturtevant.

Thunderstorm Wind in DANE, WISCONSIN
From 21-JUN-10 18:45:00 to 21-JUN-10 18:50:00 (CST-6)
Location: CROSS PLAINS
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

NWS survey team found numerous trees blown down by straight-line thunderstorm wind gusts estimated at 65 knots (75 mph).

Funnel Cloud in DANE, WISCONSIN
From 21-JUN-10 19:20:00 to 21-JUN-10 19:20:00 (CST-6)
Location: DE FOREST
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement officials reported a funnel cloud over De Forest. The time is estimated from radar imagery.

Thunderstorm Wind in MILWAUKEE, WISCONSIN
From 21-JUN-10 20:55:00 to 21-JUN-10 20:55:00 (CST-6)
Location: FRANKLIN
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Powerful thunderstorm winds snapped some large trees.

Tornado in JEFFERSON, WISCONSIN
From 21-JUN-10 19:15:00 to 21-JUN-10 19:17:00 (CST-6)
Location: BUSSEYVILLE
Tornado F-scale: EF1
Property damage: 620.00K
Crop damage: 10.00K
Reported by: NWS Storm Survey

An EF1 tornado developed in Busseyville just south of the intersection of Draves Road and Loga Road, and moved northeast about 1.3 miles and dissipated at the intersection of STH 106 and Carcajou Rd.  Thirty residential structures were minimally affected, 1 had minor damage , and 2 sustained major damage (one of which had a large tree collapse part of the structure).  A vehicle was damaged when a large tree branch fell on it.  Total private sector damage was estimated at $620,000, which included $590,000 for residential structures, $25,000 for farm buildings, and $5,000 for the damaged vehicle.  Uprooted trees and snapped tree limbs were noted along the path of the tornado.  Some crop damage was noted with a loss estimate of about $10,000.  Public sector service (non-damage) costs were limited to just debris clearance which totaled $8,000.  The exact start location was Lat.42.89798 Lon. -88.98371. The exact end location was Lat 42.91102 Lon. -88.96454. The EF-rating was based on DI 27 (TH) DOD3 which suggests wind speeds between 90 and 100 mph. The average path width was 50 yards.

Hail in MILWAUKEE, WISCONSIN
From 21-JUN-10 20:46:00 to 21-JUN-10 20:46:00 (CST-6)
Location: FRANKLIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in ROCK, WISCONSIN
From 21-JUN-10 19:07:00 to 21-JUN-10 19:12:00 (CST-6)
Location: EDGERTON
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement officials reported numerous trees blown down by thunderstorm wind gusts estimated at 65 knots (74 mph).

Hail in ROCK, WISCONSIN
From 21-JUN-10 19:15:00 to 21-JUN-10 19:15:00 (CST-6)
Location: NEWVILLE
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Emergency Manager

A severe thunderstorm produced hail up to 1.50 inches in diameter east of Newville just north of CTH N. A portion of a corn field was flattened by the hail.

Thunderstorm Wind in JEFFERSON, WISCONSIN
From 21-JUN-10 19:26:00 to 21-JUN-10 19:26:00 (CST-6)
Location: FT ATKINSON
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

A local newspaper reported that thunderstorm winds knocked down numerous trees wn southwest of Ft. Atkinson.

Funnel Cloud in SAUK, WISCONSIN
From 21-JUN-10 19:55:00 to 21-JUN-10 19:55:00 (CST-6)
Location: REEDSBURG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in DANE, WISCONSIN
From 21-JUN-10 19:15:00 to 21-JUN-10 19:15:00 (CST-6)
Location: MC FARLAND
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DANE, WISCONSIN
From 21-JUN-10 19:19:00 to 21-JUN-10 19:19:00 (CST-6)
Location: ALBION
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in JEFFERSON, WISCONSIN
From 21-JUN-10 19:24:00 to 21-JUN-10 19:24:00 (CST-6)
Location: FT ATKINSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Tornado in WAUKESHA, WISCONSIN
From 21-JUN-10 20:11:00 to 21-JUN-10 20:21:00 (CST-6)
Location: EAGLE
Tornado F-scale: EF2
Property damage: 20.60M
Crop damage: 0.00K
Reported by: Law Enforcement

An EF2 tornado developed about 1.9 miles west-southwest of the Village of Eagle, roughly 1/2 mile south-southeast of the intersection of STH 59 and CTH S, just west of CTH S and west of a horse-riding ranch, and moved east-northeast through the Eagle and then moved due east and then east-southeast before dissipating about 1.94 miles southeast of Jericho, just within Mukwonago County Park, 1000 feet east of Genevieve Drive.  Fifteen people sustained minor injuries.  One hundred thirty-four homes received minor damage, 67 homes had major damage, and 8 homes were destroyed, mainly in the southern part of the village.  Another 75 homes were minimally affected.  One business received major damage, while 18 businesses had minor damage.  The business that received major damage was a commercial horse-riding ranch/western town at the beginning of the tornado path.  Damage was inflicted upon all of the fencing, two trolleys, and 18 tables.  One of the biggest buildings on the site was twisted and turned.  A donkey was killed, four hayride wagons were lost, and 25 acres of trees were damaged.  The owner of the riding ranch saw the tornado and said it looked like the Fourth of July fireworks finale - there were thousands of lightning streaks in the cone.  All together, this tornado uprooted or damaged thousands of trees, and at least three dozen vehicles were damaged or totaled.  At Old World Wisconsin, an outdoor museum operated by the Wisconsin Historical Society near Eagle, about 2500 tress were damaged at this site alone, and a few buildings sustained minor damage.  Overall, Emergency Management officials estimated that residential damage reached $20,577,500, with business damage around $311,500, bringing total private sector damage to about $20,889,000.  A few agricultural buildings were damaged, but loss estimates were not available.  Public sector structural damage totaled only about $600, while public sector service costs (non-damage) such as debris clean-up, security and public protection, road protective measures, and other miscellaneous expenses were estimated at $101,965. The starting point location was Lat. 42.86785 Lon.-88.50307. The end point location was Lat.42.87100 Lon. -88.40003. The EF-rating was based on DI 2 (FR12) DOD 6 which suggests wind speeds between 125 to 130 mph.  On the WSR-88D Doppler radar at the nearby WFO Milwaukee (MKX), a debris-ball appeared near Eagle within a classic hook echo as the parent thunderstorm moved east.