A continuous feed of moisture, in a low to mid-level warm air advection regime, impinged along an outflow boundary draped across southern Wisconsin. This set-up fueled thunderstorms that developed, and redeveloped, along the boundary from the evening of July 14th into the early morning hours of July 15th.
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.
A continuous feed of moisture, in a low to mid-level warm air advection regime, impinged along an outflow boundary draped across southern Wisconsin. This set-up fueled thunderstorms that developed, and redeveloped, along the boundary from the evening of July 14th into the early morning hours of July 15th. Flash flooding occurred in the hills of the Wisconsin River Valley, and in the urban areas of Waukesha and Milwaukee counties, where more than 4 inches of rain fell from the evening into the overnight hours.
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 Jul 14, 2:49 PM CST, 3 hours 41 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 349 PM CDT WED JUL 14 2010 .SHORT TERM...MDT RISK CONTINUES FOR TNT WITH SVR TSTORMS AND HEAVY RAINFALL MAINLY THIS EVENING. NEW SVR SQUALL LINE FORMING JUST EAST OF MINNEAPOLIS. THIS IS A REGION 4000 J/KG OF MLCAPE WITH LITTLE CIN AND STRONG WIND SHEAR ESPECIALLY IN THE LOW LEVELS. MAIN UPPER DYNAMICS WILL MOVE FROM MN INTO CANADA TNT WITH A SLOW MOVING COLD FRONT TO MOVE ACROSS SRN WI ON THU. DESPITE DYNAMICS AND BEST WARM ADVECTION LIFTING NWD...SEVERAL MESO MODELS BUILD SQUALL LINE TO THE SW AND MOVE IT SEWD THROUGH SRN WI THIS EVENING. SINCE MODE OF CONVECTION WILL BE A LINE...DAMAGING WINDS WILL BE THE MOST WIDESPREAD THREAT...HOWEVER STRONG LOW LEVEL WIND SHEAR IN THE WRN CWA MAY BE SUFFICIENT FOR MESO VORTICES TO DEVELOP ALONG THE LEADING EDGE OF THE LINE AND PRODUCE TORNADOES. SQUALL LINE WILL MOVE TO THE RIGHT OF THE MEAN WIND...FOLLOWING CORFIDI VECTORS AND BETTER CAPE. GIVEN THIS AND WITH ONLY MODEST WINDS IN THE MID LEVELS...THE OVERALL SPEED COULD BE LOWER THAN YOUR TYPICAL SQUALL LINE. HAVE THUS MENTIONED HEAVY RAIN WITH A FLASH FLOOD THREAT. WILL HOLD OFF ON A FLASH FLOOD WATCH GIVEN RECENT DRY WEATHER...ABUNDANT VEGETATION...AND FLASH FLOOD GUIDANCE AROUND 3 INCHES. A CHANCE OF TSTORMS WILL CONTINUE ON THU WITH BEST CHANCES IN SE WI WHERE FROPA WILL NOT OCCUR UNTIL MID AFTERNOON. OTHERWISE HIGH PRESSURE WILL SETTLE FROM NE TO OHIO FOR THU NT THROUGH FRI NT WITH HIGH PRESSURE OVER WI ON SAT. A DRIER BUT CONTINUED VERY WARM AIRMASS WILL PREVAIL FRI AND SAT. .LONG TERM...WARM SUMMER TEMPS TO CONTINUE THROUGH THE EXTENDED. A WARM FRONT WILL RETURN TO THE REGION SAT NT WITH FROPA ON SUN. WEAK HIGH PRESSURE TO PREVAIL MON INTO TUE WHILE ANOTHER WARM FRONT RETURNS FOR TUE NT AND WED. && .AVIATION...SEVERE THUNDERSTORMS EXPECTED THIS EVENING INTO EARLY MORNING THURSDAY ACROSS SOUTHERN WISCONSIN. MAIN CONCERNS ARE TIMING OF THE STORMS. CURRENT MESOSCALE MODELS ARE SUGGESTING THAT STORMS WILL ORGANIZE INTO A LINE...MOVING NW TO SE THROUGH THE FORECAST AREA FROM ABOUT 00Z TO 05Z. AS CONVECTIVE DEVELOPMENT IS TRICKY TO FORECAST...THE TIMING OF THESE STORMS ARE NOT SET IN STONE. TAFS WILL LIKELY NEED TO BE AMENDED FOR TIMING AS THE STORMS DEVELOP TO THE WEST. IF A SQUALL LINE DOES DEVELOP...COULD SEE SEVERE WINDS WITHIN STORMS AS WELL AS HAIL. EXPECT CONTINUED VFR CONDITIONS OUTSIDE OF PRECIP. WITHIN SHOWERS AND STORMS...MVFR SEEMS LIKELY...WITH IFR AND LIFR POSSIBLE IN THE HEAVIEST STORMS. CHANCE FOR STORMS WILL CONTINUE LATER IN THE NIGHT AND INTO THURSDAY MORNING AS FRONTAL BOUNDARY LINGERS IN THE AREA. QUIETER CONDITIONS SHOULD RETURN DURING THE AFTERNOON THURSDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ062-067>069. LM...NONE. && SHORT/LONG TERM...20 AVIATION/MARINE...07
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 715 PM CDT WED JUL 14 2010 WIZ046-047-051-052-056>060-062>072-152115- MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE- WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE- LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA- 715 PM CDT WED JUL 14 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN. .DAY ONE...THIS EVENING AND TONIGHT THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT FOR AREAS ALONG AND NORTH OF A LINE FROM SHEBOYGAN TO MINERAL POINT...AND A SLIGHT RISK ACROSS THE REST OF SOUTH CENTRAL AND SOUTHEAST WISCONSIN. DAMAGING WINDS...LARGE HAIL...AND ISOLATED TORNADOES ARE POSSIBLE WITH THE SEVERE STORMS. A TORNADO WATCH IS IN EFFECT UNTIL 1 AM FOR ALL OF SOUTHERN WISCONSIN. IN ADDITION...GIVEN THE SURGE OF MOISTURE INTO SOUTHERN WISCONSIN...THE THUNDERSTORMS THIS EVENING WILL YIELD HIGH RAINFALL RATES. LOCAL FLASH FLOOD GUIDANCE SUGGESTS IT WILL TAKE 2 TO 4 INCHES OF RAIN IN RURAL AREAS IN A 3 HOUR WINDOW FOR FLASH FLOODING TO OCCUR. IN URBAN AREAS...IT ONLY TAKES A QUICK 1 TO 2 INCHES TO CAUSE FLOODING PROBLEMS. GIVEN THE HIGH PRECIPITABLE WATER AND EXPECTED SPEED OF THE THUNDERSTORMS...THERE WILL BE A FLASH FLOODING THREAT FOR NEARLY ALL OF SOUTHERN WISCONSIN AS A COMPLEX OF THUNDERSTORMS MOVES THROUGH THE AREA THIS EVENING. AN AIR QUALITY WATCH ISSUED BY THE WISCONSIN DEPARTMENT OF NATURAL RESOURCES IS IN EFFECT UNTIL 11 PM FOR A PORTION OF SOUTHEAST WISCONSIN...DUE TO THE POSSIBLE ELEVATED LEVELS OF OZONE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE CHANCE OF THUNDERSTORMS CONTINUES THROUGH THURSDAY MORNING AND INTO THE AFTERNOON...THE BEST CHANCE ACROSS THE SOUTHEAST AS A WEAK COLD FRONT MOVES THROUGH. THERE IS A CHANCE OF THUNDERSTORMS AGAIN SATURDAY NIGHT AND SUNDAY...WITH A SLIGHT CHANCE FOR STORMS RETURNING TUESDAY AFTERNOON IN THE WEST. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL LIKELY BE NEEDED TONIGHT. LMZ643>646-152115- SHEBOYGAN TO PORT WASHINGTON WI- PORT WASHINGTON TO NORTH POINT LIGHT WI- NORTH POINT LIGHT TO WIND POINT WI- WIND POINT WI TO WINTHROP HARBOR IL- 715 PM CDT WED JUL 14 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN. .DAY ONE...THIS EVENING AND TONIGHT THUNDERSTORMS ARE EXPECTED THIS EVENING INTO TONIGHT...WITH A SLIGHT RISK OF SEVERE THUNDERSTORMS. DAMAGING WINDS...LARGE HAIL...AND ISOLATED TORNADOES ARE POSSIBLE WITH THE SEVERE STORMS. A TORNADO WATCH IS IN EFFECT UNTIL 1 AM. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH WEDNESDAY A CHANCE OF THUNDERSTORMS CONTINUES THURSDAY MORNING AND INTO THE AFTERNOON AS A WEAK COLD FRONT MOVES THROUGH. THERE IS A CHANCE OF THUNDERSTORMS AGAIN SUNDAY AND A SLIGHT CHANCE OF THUNDERSTORMS TUESDAY NIGHT. DDV WWW.WEATHER.GOV/MKX
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 437 PM CDT WED JUL 14 2010 WIZ051-052-142230- FOND DU LAC-SHEBOYGAN- 437 PM CDT WED JUL 14 2010 ...STRONG THUNDERSTORM MOVING INTO NORTHERN FOND DU LAC COUNTY... AT 432 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER SOUTHEASTERN WINNEBAGO COUNTY...MOVING SOUTHEAST AT 25 MPH. WINDS GREATER THAN 40 MPH...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THIS STORM. * THE THUNDERSTORM WILL BE NEAR... PEEBLES AND PIPE BY 450 PM CDT... JOHNSBURG BY 455 PM CDT... CALVARY BY 500 PM CDT... MOUNT CALVARY BY 505 PM CDT... ST. CLOUD AND SAINT CLOUD BY 510 PM CDT... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. FRANKS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 608 PM CDT WED JUL 14 2010 WIZ046-047-051-150015- FOND DU LAC-GREEN LAKE-MARQUETTE- 608 PM CDT WED JUL 14 2010 ...A LINE OF STRONG THUNDERSTORMS MOVING INTO MARQUETTE...GREEN LAKE AND NORTHWEST FOND DU LAC COUNTIES... AT 605 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 17 MILES NORTHWEST OF BERLIN TO 65 MILES WEST OF BERLIN...MOVING EAST TO SOUTHEAST AT 35 MPH. ONE HALF INCH DIAMETER HAIL...WINDS GREATER THAN 40 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THESE STORMS. IF THESE STORMS BECOME STRONGER...SEVERE WEATHER WARNINGS MAY BE NEEDED. * THUNDERSTORMS WILL BE NEAR... WESTFIELD BY 640 PM CDT... BERLIN BY 645 PM CDT... PRINCETON BY 700 PM CDT... MONTELLO BY 705 PM CDT... GREEN LAKE BY 710 PM CDT... RIPON BY 715 PM CDT... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE PASSED. GEHRING
The Green Bay radar (KGRB), 91 km away, was scanning. The volume nearest the first event began at 00:30 UTC.
16 thunderstorm wind, 4 flash flood, 1 lightning. Local standard time, as filed.
A trained spotter reported trees blown down by thunderstorm wind gusts estimated at 52 knots (60 mph).
The public reported a thunderstorm wind gust estimates at 50 knots (58 mph).
The public reported a thunderstorm wind gust estimated at 60 mph (52 knots).
The public reported trees blown down by thunderstorm wind gusts estimated at 52 knots (60 mph).
The emergency manager of Washington County reported trees and power lines blown down by thunderstorm wind gusts in Hartford and a few other locations in the county.
A trained spotter reported trees and power lines blown down by thunderstorm wind gusts estimated at 70 mph (61 knots) along a path from the Wisconsin Dells to Portage.
Fire department personnel reported thunderstorm wind gusts up to an estimated 52 knots (60 mph).
Law enforcement personnel reported trees blown down by thunderstorm wind gusts estimated at 56 knots (65 mph).
The Sauk County Emergency Manager reported one to three feet of water over some roads, mainly in the northern portion of the county...with sandbagging operations in Rock Springs along the rapidly rising Baraboo River. A trained spotter reported street flooding along Highway 33 in Baraboo. The flooding was the result of heavy rains from strong to severe thunderstorms crossing the region. A farmer near La Valle lost 30 head of cattle that drowned when they left high ground into the rushing waters of the Little Baraboo River. Minor crop damage was also noted.
Law enforcement officials reported trees and power poles blown down by thunderstorm wind gusts estimated at 65 knots (75 mph).
A trained spotter estimated thunderstorm wind gusts up to 52 knots (60 mph).
The public reported trees blown down by thunderstorm wind gusts estimated up to 56 knots (70 mph).
The West Bend Fire Department responded to four calls for trees on fire due to lightning strikes and power line damage due to lightning strikes, including near the intersection of CTH NN and Scenic Rd. in West Bend.
Law enforcement reported a power pole snapped by strong thunderstorm wind gusts estimated up to 65 knots (75 mph).
Law enforcement officials reported trees blown down by thunderstorm wind gusts estimated up to 52 knots (60 mph).
Law enforcement officials reported trees blown down by thunderstorm wind gusts estimated up to 52 knots (60 mph).
The public reported trees blown down by thunderstorm wind gusts estimated up to 52 knots (60 mph).
Law enforcement officials reported trees blown down by thunderstorm wind gusts estimated up to 52 knots (60 mph).
Heavy rain from strong to severe thunderstorms produced 3 to 4 inch rainfall amounts in only a couple of hours. Flash flooding from the heavy rain flooded basements in West Allis; blocked the east-bound lanes of Greenfield Avenue between 116th St. and 124th St.; blocked 82nd St. and 83rd St. near Orchard St. with two to three feet of water over the roads that stalled cars; made I-794 at the south end of the Hoan Bridge impassable due to high water over the roadway; and quickly filled the 2500 block of N. Humboldt Ave. with 2 feet of water.
Heavy rain from strong to severe thunderstorms that moved across the region produced flash flooding from 3 to 4-inch rainfall that fell in only a couple of hours. All of the I-94 ramps in Brookfield were closed for a time due to high water. Water covered Sunset Drive at a railroad intersection about 1 mile southwest of Waukesha. Trained spotters reported 2 feet of water flowing through the intersection of Calhoun Rd and Beloit Rd., as well as Overland Trail near Brookfield Rd. in New Berlin.
The Columbia County Emergency Manager reported gravel shoulder wash-outs on several roads and one to two feet of water on low-lying roads from heavy rains as strong to severe thunderstorms crossed the region. Minor crop damage was also noted.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2010Every state in 2010This day in weather historyWarnings in Wisconsin, July 2010
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: 249820, 249815, 249822, 249826, 249830, 249837, 249843, 249847, 249911, 249852, 249856, 249923, 254481, 249898, 249928, 249929, 249931, 249930, 251619, 251629, 249918.