During the afternoon and evening hours of August 22nd, the second round of storms for the calendar day moved east across south-central and southeast Wisconsin. The clusters or short lines of storms moved east at a speed of about 30 knots (35 mph), and generated damaging downburst straight-line winds that toppled trees and power-lines, and heavy rains that triggered flash flooding.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MKX wrote it up.
During the afternoon and evening hours of August 22nd, the second round of storms for the calendar day moved east across south-central and southeast Wisconsin. The clusters or short lines of storms moved east at a speed of about 30 knots (35 mph), and generated damaging downburst straight-line winds that toppled trees and power-lines, and heavy rains that triggered flash flooding. Synoptically, a stationary front stretched from northern Iowa to Wisconsin/Illinois border. Warm, moist, unstable air flowed north over the front in association with an upper-level short-wave trough, resulting in thunderstorm generation. Hourly rainfall rates peaked around 2 inches.
By the end of August, 2007, many locations in south-central and southeast Wisconsin would establish new August rainfall records, and all-time/any month rainfall records. Many locations measured 10 to over 20 inches for the month of August, 2007, or about 200% to over 400% of normal. Normal August precipitation in southern Wisconsin is about 4 to 4.25 inches. Unofficially, about 25 inches fell at a location 2W of Barneveld, Iowa County. Specific August, 2007, monthly totals are listed in the various flash flood events of August 18-19th and August 22nd.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Milwaukee, WI wrote its last area forecast discussion before the first event at Aug 22, 1:00 PM CST, 2 hours 42 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 200 PM CDT WED AUG 22 2007 .DISCUSSION...CONCERN REMAINS WITH FLOODING POTENTIAL AS ACTIVE WET PATTERN TO CONTINUE INTO FRIDAY NIGHT. PATTERN CHANGE BRINGS DRIER WEATHER FOR THE WEEKEND. .SHORT TERM...IMMEDIATE CONCERN IS WITH CONVECTION UPSTREAM ACROSS NRN/WRN IA FINGERING INTO WEST CENTRAL AND CENTRAL WI EARLY THIS AFTERNOON. WK SFC BNDRY EXTENDS FM NE WI INTO NE IA...BUT THIS IS TOUGH TO DEFINE GIVEN WEAK FLOW AND DISTURBED ATMOSPHERE FROM CONVECTION UPSTREAM. THE GFS AND THE NAM ARE HANDLING THIS EARLY CONVECTION VERY DIFFERENTLY. NAM SHOWS IT MOSTLY SOUTH OF THE AREA THROUGH 06Z INTO 12Z. WHILE THE GFS PUSHES IT MOSTLY ENE WITH TIME...RIGHT INTO THE NW HALF OF THE CWA. THE GFS SOLUTION IS ALREADY LOOKING LIKE A BETTER FIT WITH REALITY. HPC QPF FIELDS ARE FOLLOWING CLOSER TO THE GFS AS WELL. SHOULD SEE THE HEAVIEST RAIN NW OF MADISON...AN AREA THAT CAN/T AFFORD MUCH MORE RAIN. A FLASH FLOOD WATCH WAS ISSUED EARLIER FOR ALL BUT THE NRN TIER OF THE CWA TONIGHT. THE SE CWA IS SOAKED AND IF THE COLD POOL WITH THAT CONVECTION ORGANIZES A BIT MORE...THAT COLD POOL INFLUENCE AND THE MEAN STEERING CURRENTS WOULD TAKE THAT CONVECTION ON A MORE EASTERLY TRAJECTORY...INTO EASTERN AND SOUTHEAST WISCONSIN. RIVERS IN THE SE ARE VERY HIGH. MANY REPORTS OF STANDING WATER. A SHOT OF HEAVY RAIN COULD BE PROBLEMATIC. THUS THE MORE WIDESPREAD COVERAGE OF THE WATCH. SOME S/W ENERGY APPEARS TO EJECT OUT OF THE SW AND INTO THE GREAT LAKES LATE TONIGHT AND THU...SOMEWHAT ENERGIZED BY A DIGGING TROUGH NOW MOVING THROUGH THE NRN ROCKIES. THE NAM LOOKS TO OVER DEVELOP THIS SYSTEM WHILE THE GFS...AGAIN...IS LOOKING BETTER. THE NAM HAS AN UNSEASONABLY STRONG H8 LLV JET IN EXCESS OF 60KTS ACROSS KS BY 12Z THU AND PUSHES IT OVER THE CWA BY OOZ. I PREFER THE MORE RESERVED SOLUTION OF THE GFS...STILL 40KTS...BUT POINTING A BIT MORE SOUTH AND EAST OF THE CWA THAN THE NAM. SINCE THE NAM HAS BEEN STRONGLY BIASED WITH A TOO FAR NORTH SOUTION TO THE QPF AND FORCING FIELDS THIS SUMMER...IT OFFERS SUPPORT FOR FOLLOWING THE GFS. THE FRONTOGENESIS IS WEAK SINCE THE BAROCLINIC ZONE IS WELL NORTH ACROSS WI. BUT THE LLV ISENTROPIC LIFT IS IMPRESSIVE. THE LOW TRACKS ALONG THE FRONT LOCATED ACROSS OUR AREA. THIS SHOULD SPELL MORE RAIN FOR THU INTO THU NGT. THE FRONT MOVES LITTLE IN THE WAKE OF THAT LOW AS YET ANOTHER SFC LOW EJECTS OUT OF THE SOUTHWEST ON FRIDAY. MORE RAIN. SO OUR THREAT FOR MORE FLOODING RAINS OVER THE NEXT 48 TO 60 HOURS IS VERY HIGH AS A SERIES OF WAVES MOVES UP THE SFC FRONT IN A SW FLOW ALOFT. WE WILL LIKELY BE EXTENDING OR RE-ISSUING THE FLASH FLOOD WATCHES AS WE GAIN MORE CLARITY IN THE EVOLUTION OF THIS SYSTEM. A PATTERN CHANGE ARRIVES BY SATURDAY AS A CANADIAN HIGH BUILDS SOUTH. COULD BE DRY INTO MONDAY. INTERESTING ANALYSIS OF THE GFS FOR TUE SHOWS THAT IT/S PROGGED QPF FOR US ON TUE/TUE NIGHT MAY BE THE REMNANTS OF HURRICANE DEAN. A BIT DIFFICULT TO PIN THAT ONE DOWN FOR SURE. && .AVIATION...MAIN CONCERN THIS PERIOD IS NRN IA MCS AND HOW IT WILL EVOLVE TO AFFECT SRN WI THIS EVE AND OVERNIGHT. WILL GRADUALLY SPREAD THE MCS ACRS THE AREA OVERNIGHT TNGT AND LOWER CIGS A BIT. NAM MOS HINTS AT MVFR CIGS IN MSN WHILE GUID UNANIMOUS WITH VFR CIGS IN MKE. WILL NEVERTHELESS HINT AT LOWER CIGS WITH THE CONVECTION BUT FOR THE MOST PART KEEP THINGS VFR. BUFKIT AND LLVL RH PROGS IMPLY SUSTAINED LOWER CIGS SHOULD REMAIN TO THE NORTH OF MKE AND MSN WITH THE PSBL BRIEF DROP DOWN TO MVFR/IFR CIGS IN THE STRONGER CONVECTION LATER TNGT AND ERLY THU MRNG. WILL ALSO CARRY MVFR BR LATER TNGT AND HAVE MVFR VSBYS WITH THE STORMS...THO IFR VSBYS NOT OUT OF THE QUESTION IN THE HEAVIER DOWNPOURS. && .MKX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH THURSDAY MORNING FOR WIZ056>060-062>072. && DAVIS
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 627 AM CDT WED AUG 22 2007 WIZ046-047-051-052-056>060-062>072-231000- MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE- WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE- LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA- 627 AM CDT WED AUG 22 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN. .DAY ONE...TODAY AND TONIGHT THERE WILL BE A CHANCE OF THUNDERSTORMS THIS AFTERNOON WITH THUNDERSTORMS LIKELY TONIGHT. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND TONIGHT. THE MAIN THREAT WILL BE DAMAGING WINDS. LARGE HAIL IS POSSIBLE. HEAVY RAIN WITH THE STRONGER STORMS WILL AGGRAVATE ANY EXISTING FLOODING PROBLEMS. HEAT INDEX READINGS MAY REACH AROUND 95 DEGREES AROUND MID AFTERNOON. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THUNDERSTORMS ARE LIKELY THURSDAY AND THERE IS A CHANCE OF THUNDERSTORMS THURSDAY NIGHT THROUGH FRIDAY NIGHT. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY THROUGH FRIDAY. THERE IS THE POTENTIAL FOR HEAVY RAIN THURSDAY AND FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND TONIGHT. LMZ643>646-665-231000- SHEBOYGAN TO PORT WASHINGTON- PORT WASHINGTON TO NORTH POINT LIGHTHOUSE- NORTH POINT LIGHTHOUSE TO WIND POINT- WIND POINT TO WINTHROP HARBOR ILLINOIS- WISCONSIN ADJACENT OPEN WATERS OF LAKE MICHIGAN TO MID LAKE- 627 AM CDT WED AUG 22 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT THERE WILL BE A CHANCE OF THUNDERSTORMS THIS AFTERNOON WITH THUNDERSTORMS LIKELY TONIGHT. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND TONIGHT. THE MAIN THREAT WILL BE DAMAGING WINDS. LARGE HAIL IS POSSIBLE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THUNDERSTORMS ARE LIKELY THURSDAY AND THERE IS A CHANCE OF THUNDERSTORMS THURSDAY NIGHT THROUGH FRIDAY NIGHT. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY THROUGH FRIDAY. TZ WWW.WEATHER.GOV/MKX
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
425 PM CDT WED AUG 22 2007
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0415 PM FLOOD 4 SW SUN PRAIRIE 43.14N 89.29W
08/22/2007 DANE WI TRAINED SPOTTER
12 INCHES OF WATER ACROSS ROAD
&&
KRRThe Milwaukee radar (KMKX), 18 km away, was scanning. The volume nearest the first event began at 21:43 UTC.
16 thunderstorm wind, 14 flash flood. Local standard time, as filed.
Powerful thunderstorm wind gusts up to 52 knots (60 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 56 knots (65 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 56 knots (65 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 58 knots (68 mph) toppled several large trees and damaged some power-lines.
Heavy rain from thunderstorms resulted in scattered flash flood conditions in the Beaver Dam to Horicon area. Fast-flowing water depths of 1 to 2 feet were reported, as well as basement flood damage in about 20 homes. Sandbagging occurred in Beaver Dam. There were reports of soil erosion and some crop damage.
Flash flooding occurred in the Lake Mills to Watertown area due to repeated thunderstorms with heavy rains on top of a saturated ground. Numerous roads were covered with fast-flowing water depths of 6 inches to 1 foot. Hourly rainfall rates were 1.5 to 2 inches based on WSR-88D Doppler radar estimates. Soil erosion and crop damage also occurred on several other farms in that area. Additionally, a few basements had water damage to contents. Most creeks and streams in the area exceeded flood stage by one to 2 feet.
August, 2007, rainfall totals include: 10.64 in Ft. Atkinson, 12.68 in Jefferson, 17.75 in Lake Mills, 14.39 in Watertown, 12.54 in Waterloo, and 12.78 at the NWS office 3.8SE of Sullivan.
Powerful thunderstorm wind gusts up to 52 knots (60 mph) toppled several large trees and damaged some power-lines in the area from Sussex to Pewaukee to Brookfield.
Powerful thunderstorm wind gusts up to 52 knots (60 mph) toppled several large trees and damaged some power-lines.
Heavy rain from thunderstorms resulted in scattered flash flood conditions in the Watertown to Rubicon area. Fast-flowing water depths of 1 to 2 feet were reported, as well as basement flood damage in about 50 homes. Several homes had water flowing in through windows as well as through wall cracks. There were reports of soil erosion and some crop damage. A resident on north side of Watertown picked up 1.84 of rain in 28 minutes, and a total of 3.22 inches from 4 pm to 520 pm.
Flash flooding occurred due to repeated thunderstorms with heavy rains on top of a saturated ground. From Madison to Sun Prairie many roads had fast-flowing water depths of 6 inches to 1 foot, and several were closed. Sandbagging also took place to control the flash flooding. A 1-hour rainfall total of 2.26 inches was measured by a spotter in Madison. Soil erosion and crop damage also occurred on several other farms in that area. Additionally, a few basements had water damage to contents.
August, 2007, rainfall totals include: 15.18 at Madison Truax Field, 14.58 at the UW-Charmany Farm, 14.92 at mazomanie, 14.43 in Middleton, 18.48 near Mt. Horeb, 16.37 in Stoughton, 15.74 in Sun Prairie, and 13.49 at the UW Arboretum. Up to 20 may have fallen in the southwest corner.
Several rounds of thunderstorms with heavy rains on top of a saturated ground resulted in scattered flash flooding from the Hartland area to the City of Waukesha. Many roads in this area had at least 6 inches to 1 foot of fast flowing water covering them. At least a couple dozen homes in this area had basement flooding and sewage backups and needed to be pumped out. A vehicle got stuck in 3 to 4 feet deep the flood waters in the Village of Pewaukee, where sandbagging took place. Soil erosion and crop damage was also noted.
August, 2007, rainfall totals include: 10.72 in Oconomowoc, and 9.62 in Waukesha. In Milwaukee County, Milwaukee Mitchell Field measured 7.92 for the month, which makes August, 2007 the 4th wettest August in Milwaukee.
Powerful thunderstorm wind gusts up to 52 knots (60 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 52 knots (60 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 52 knots (60 mph) toppled several large trees and damaged some power-lines.
Heavy rain from thunderstorms resulted in flash flood conditions northeast of Hartford. Rainfalls of 2 to 3 inches were measured in the area. A flower farm reported substantial damage amounts due to the heavy rains, with some small hail adding insult. Soil erosion and crop damage also occurred on several other farms in that area. in the Watertown to Rubicon area. Fast-flowing water depths of 6 inches to 1 foot were also reported on a couple roads. Additionally, a few basements had water damage to contents.
Powerful thunderstorm wind gusts up to 68 knots (78 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 56 knots (65 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 56 knots (65 mph) toppled several large trees and damaged some power-lines.
Powerful thunderstorm wind gusts up to 52 knots (60 mph) toppled several large trees and damaged a couple power-lines.
Powerful thunderstorm wind gusts up to 56 knots (65 mph) toppled several large trees and damaged a couple power-lines.
Powerful thunderstorm wind gusts up to 65 knots (75 mph) toppled several large trees and damaged seveal power-lines. A large pine tree 100 feet tall was snapped at the 10 foot level.
Flash flooding occurred in the Oregon vicinity due to repeated thunderstorms with heavy rains on top of a saturated ground. In Oregon, numerous roads were covered with fast-flowing water depths of 6 inches to 1 foot. Sandbagging also took place to control the flash flooding. Hourly rainfall rates were 1.5 to 2 inches based on WSR-88D Doppler radar estimates. Soil erosion and crop damage also occurred on several other farms in that area. Additionally, a few basements had water damage to contents. All creeks and streams around Oregon were two to three feet above flood stage.
Several rounds of thunderstorms with heavy rains on top of a saturated ground resulted in scattered flash flooding from the Evansville area to the Janesville vicinity. Water damage to basement contents and/or basement walls, as well as fast-flowing water depths of 6 inches to 1 foot on roads, were reported in the Civil Towns of Avon, Fulton, Magnolia, Union, and Plymouth. Some soil erosion, gravel washouts, and crop damage were noted. Badfish Crreek and Allen Creek just east and northeast of Evansville exceeded flood stages by 3 to 5 feet and overflowed adjacent roads.
August, 2007, rainfall totals include: 17.39 at Afton, 13.15 in Beloit, 16.24 in Clinton, 15.22 in Milton, and over 17 in Janesville.
Several rounds of thunderstorms with heavy rains on top of a saturated ground resulted in a flash flood event in hilly Mineral Point. Fast-flowing water quickly flooded the city' streets to a depth of 6 inches to 2 feet. One residential home's driveway was washed out by the flood waters. A few homes in the city sustained water damage to basement contents. Some soil erosion and crop damage were noted in the surrounding countryside.
August, 2007, rainfall totals include: 20.12 in Dodgeville, and an unofficial 25 at a location 2W of Barneveld.
Several rounds of thunderstorms with heavy rains on top of a saturated ground resulted in scattered flash flood events across the entire county of Walworth. Fast-flowing water reached depths of 6 inches to 2 feet at the following locations: STH 11 just east of STH 89 (about 3N of Darien), Plank Road just northeast of Elkhorn, Highway 12 and Potter Road, CTH L near East Troy, and several roads around Richmond. Johnson Creek and Turtle Creek areas between Richmond and I-43 exceeded flood stage. At least a couple dozen homes had water damage to basement contents, or sewage backups. Two basement walls of a home in the Civil Town of Lafayette, or about 2 miles east-northeast of Elkhorn, collapsed. Some soil erosion and minor crop damage were noted in the county. A couple minor landslides occurred along the shoreline of Geneva Lake.
August, 2007, rainfall totals include: 12.83 in Genoa City, and 12.67 in Whitewater.
Several rounds of thunderstorms with heavy rains on top of a saturated ground resulted in flash flooding from the Sturtevant area into the city of Racine. Fast-flowing water reached depths of 6 inches to 2 feet on several roads. The following roads were closed: Intersection of CTH X and Southwood Drive, Intersection of STH 11 and STH 32, and intersection of CTH H and CTH KR. At least a couple dozen homes had water damage to basement contents, or sewage backups. Some soil erosion and minor crop damage were noted in the area.
August, 2007, rainfall totals include: 11.47 in Burlington, 11.58 in Racine, 11.04 at the Racine Airport, 12.41 in Union Grove, and 13.75 in Waterford.
Flash flooding occurred south of the Village of Shullsburg due to repeated thunderstorms with heavy rains on top of a saturated ground. CTH O south of Shullsburg was coverd with fast-flowing water depths of 6 inches to 1 foot. One mile south of the village a mudslide occurred onto CTH O. Hourly rainfall rates were 1.5 to 2 inches based on WSR-88D Doppler radar estimates. Soil erosion and crop damage also occurred on several other farms in that area. Additionally, a few basements had water damage to contents. Most creeks and streams in the area exceeded flood stage by one to two feet.
August, 2007, rainfall totals include: 16.98 at Arygle, and 17.22 at Blanchardville.
Several rounds of thunderstorms with heavy rains on top of a saturated ground resulted in another round of scattered flash flooding across Green County. At least another 150 residents sustained water damage to basement contents and/or basement walls. Two homes in Browntown had basements on the verge of collapsing. One farm home near Brooklyn had 5 feet of water in the basement and the basement walls cracked. Two silos on the same property had cracking due to water accumulation. In the city of Brodhead, a sink hole developed which resulted in the sewer system collapsing at that location. Road damages (gravel washouts or culverts) were scattered around the county, and totaled 91,000. Several roads were closed over the eastern third of the county due to either fast-flowing water or high water levels. Many other roads across the county had at least 6 inches to 1 foot of fast flowing water covering them. About 20 homes in Albany had basement flooding and sewage backups and needed to be pumped out. In some cases water depths were almost to the basement ceiling! Several homes and businesses in New Glarus had sewage backups. A home on CTH Y near Monroe had a partial collapse of two basement walls. A mudslide occurred on CTH M just south of Jordon Center. Soil erosion and crop damage was also noted. Refer to the August 18-19, 2007, Flash Flood event for Green County for related information.
August, 2007, rainfall totals include: 15.57 at Brodhead, 15.43 in Monroe, and 20.20 in New Glarus.
Several rounds of thunderstorms with heavy rains on top of a saturated ground resulted in flash flooding from the Sturtevant area into the city of Racine. STH 50 between STH 75 and STH 83 was closed in several spots due to water depths of 3 to 5 feet. Some local residents indicated that this was the highest water levels they've ever seen. The Fox River and Des Plains river exceeded flood stage. Sandbagging occurred and a berm was built in Wheatland. At least a couple dozen homes had water damage to basement contents, or sewage backups. Some soil erosion and crop damage were noted in the area.
August, 2007, rainfall totals include: 11.50 in Kenosha, 10.78 at the Kenosha Airport, 9.96 in Paddock Lake, and 12.18 in Twin Lakes.
Powerful thunderstorm wind gusts up to 56 knots (65 mph) toppled several large trees and damaged a couple power-lines. One tree landed on a home and damaged the roof and a skylight.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2007Every state in 2007This day in weather historyWarnings in Wisconsin, August 2007
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 57629, 57622, 57613, 57624, 57494, 57504, 57632, 57626, 57495, 57500, 57564, 57633, 57650, 57653, 57497, 57635, 57656, 57655, 57658, 57657, 57660, 57502, 57573, 57576, 57582, 57604, 57507, 57508, 57609, 57661.