Flooding and Damaging Winds in Wisconsin, September 7, 2001

Name: Flooding and Damaging Winds in Wisconsin, September 7, 2001
Start: 2001-09-07T17:45
End: 2001-09-07T23:00
Location: Wisconsin

September 7, 2001 · NWS MKX · 16 events in 12 counties and zones

Where it happened

Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $85,000
Crop damage: None recorded
Events: 16

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.

What happened

The episode as NWS MKX wrote it up.

The second of two rounds of severe thunderstorms to affect southern Wisconsin on September 7th struck parts of the south-central and southeast counties in the early evening hours. A north-south line of storms moving east through southern Wisconsin generated powerful straight-line downburst winds that toppled many large trees in parts of Iowa, Lafayette, Sauk, Coumbia, Marquette, Green Lake, Dane, Green, Rock, Jefferson, Waukesha, and Walworth Counties. Scattered power outages were also noted, resulting in the loss of electrical power to about 1000 customers in southeast Wisconsin. Law enforcement officials and trained spotters estimated wind gusts to be in the 50 to 56 knot range (58 to 65 mph). However, thunderstorm winds probably topped out around 65 knots (75 mph) in the area about 4 miles southeast of Lake Delton where newspaper accounts indicated that a silo and pole shed were blown down, and other buildings were damaged. One of the large trees that were toppled in Beloit damaged two vehicles, and trapped passengers in one of them for about one hour. In addition, heavy rains of 1 to 2 inches accompanied some of the storms, resulting in flooded roads in and around Madison (Dane Co.) and Beloit (Rock Co.). Water depths on some of Madison's and Beloit's roads were 1 to 2 feet deep in low spots, and several vehicles in Madison stalled. In Beloit, up to 1.64 inches of rain was measured, while 1.85 inches fell at Madison's Truax Field. Synoptically, low pressure moved northeast through northwest Wisconsin. Surface dewpoints were in the lower 70s with maximum air temperatures in the mid 80s. The individual thunderstorm cells moved northeast at 35 to 43 knots (40 to 50 mph).

What forecasters said that day

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 Sep 7, 1:30 PM CST, 4 hours 15 minutes earlier.

Area forecast discussion, Sep 7, 1:30 PM CST, 4 hours 15 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
230 PM CDT FRI SEP 7 2001

FCST FOCUS IS STILL ON TIMING OF RN EVENTS WITHIN A VERY COMPLICATED
WX PATTERN.

IN THE SHORT TERM...SHRTWV LIFTING UP THRU MN AND IA CONTS TO SPRD
SHWRS AND STORMS ACRS CWA. WL CONFORM ZN WORDING TO CNVTV
COVERAGE AT ISSUANCE TIME...POPS MAY NOT BE NEEDED.

THERE IS A SGFNT DIFFERENCE IN MODEL SOLUTIONS FOR OVERALL PICTURE
AFTER THAT. RGL DOES NOT BRING CDFNT THRU CWA NRLY AS FAST AS OTRS...
THIS WUD HAVE A PROFOUND EFFECT ON TMPS AND CNVTV TRENDS.

WE PREFER ETA/AVN HANDLING OF SITUATION...BASICALLY RELATING
EVENTS TO MOVMT OF STG VORT CNTR NOW IN BASE OF WRN UPR TROF. STLT
LOOPS SHW THIS FEATURE WELL...NOW SPINNING EWD THRU CO.

ABV MODELS LIFT THE VORT OUT INTO UPR MIDWEST TMRW...ACCOMPANIED BY
COMMA CLD BEST DEPICTED BY AVN. SO WL GO WITH HI POPS DURG THE DAY.
THIS IN TURN PULLS SFC LO THRU CWA AND SWINGS CDFNT THRU SHORTLY
THEREAFTER.

THIS WUD TAKE MOST OF THE PRCP OUT OF CWA BY SAT EVE. SO WE MAY NOT
MENTION RN CHC SAT NGT INTO SUNDAY...THEN PICK IT UP AGN AFT THAT AS
NXT WV LIFTS OUT OF UPR TROF.

WL FLW MAV GUID NUMBERS...WHICH DEPICT ABV SCENARIO MUCH BETTER.

.MKX...NONE.

NJ

In the hours before

Local storm report, Sep 7, 12:49 PM CST, 4 hours 56 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
149 PM CDT FRI SEP 07 2001

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1235 PM    LODI                      WI   60 MPH TSTM GUST
09/07/01   COLUMBIA                       REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

1245 PM    5 NE PORTAGE              WI   WIND DAMAGE
09/07/01   COLUMBIA                       TREES DOWN. REPORTED BY
                                          LAW ENFORCEMENT OFFICIAL.

1250 PM    7 W BERLIN                WI   WIND DAMAGE
09/07/01   GREEN LAKE                     TREES AND SHED DOWN.
                                          REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

1255 PM    WINDSOR                   WI   WIND DAMAGE
09/07/01   DANE                           TREES... 2 TO 3 INCH IN
                                          DIAMETER DOWN. REPORTED
                                          BY STORM SPOTTER.

0100 PM    PRINCETON                 WI   60 MPH TSTM GUST
09/07/01   GREEN LAKE                     TREES...BRANCHES DOWN.
                                          REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

Special weather statement, Sep 7, 1:06 PM CST, 4 hours 39 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
206 PM CDT FRI SEP 7 2001

WIZ046-047-057-063-069-071915-
COLUMBIA-DANE-GREEN LAKE-MARQUETTE-ROCK-
206 PM CDT FRI SEP 7 2001

...PART OF SEVERE THUNDERSTORM WATCH 713 CANCELED...

SEVERE THUNDERSTORM WATCH NUMBER 713 IS NO LONGER IN EFFECT FOR
MARQUETTE...GREEN LAKE...COLUMBIA...DANE AND ROCK COUNTIES. THE
LINE OF SEVERE STORMS HAS MOVED EASTWARD OUT OF THE AREA.

NJ

Special weather statement, Sep 7, 1:14 PM CST, 4 hours 31 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
214 PM CDT FRI SEP 7 2001

WIZ051-052-058>060-064>066-070>072-072030-
DODGE-FOND DU LAC-JEFFERSON-KENOSHA-MILWAUKEE-OZAUKEE-RACINE-
SHEBOYGAN-WALWORTH-WASHINGTON-WAUKESHA-
214 PM CDT FRI SEP 7 2001

...SEVERE THUNDERSTORM WATCH UNTIL 5 PM...

AT 210 PM...WEATHER RADAR SHOWED A LINE OF SCATTERED THUNDERSTORMS
EXTENDING FROM PLYMOUTH IN SHEBOYGAN COUNTY TO DELAFIELD IN WAUKESHA
COUNTY...MOVING NORTHEAST NEAR 30 MPH. IF IT HOLDS TOGETHER...THE
LINE SHOULD PASS THROUGH SHEBOYGAN...PORT WASHINGTON...AND
POSSIBLY MILWAUKEE BY 330 PM.

THE STRONGEST STORMS WERE NEAR PLYMOUTH...WHILE STORMS IN THE
SOUTHERN PART OF THE LINE HAD WEAKENED SOMEWHAT SINCE 145 PM. SOME
NEW STORMS HAD POPPED UP OVER OZAUKEE AND MILWAUKEE COUNTIES AHEAD OF
THE MAIN LINE.

NO SEVERE WEATHER HAS BEEN REPORTED SINCE 130 PM...BUT AREA
RESIDENTS AND TRAVELERS SHOULD REMAIN ON THE ALERT FOR THIS
POSSIBLITY.

NJ

Special weather statement, Sep 7, 2:10 PM CST, 3 hours 35 minutes before

WIZ046-047-051-052-056>060-062>072-072045-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
310 PM CDT FRI SEP 7 2001

...SEVERE THUNDERSTORM WATCH CANCELLED...

THE SEVERE THUNDERSTORM WATCH WHICH HAD BEEN IN EFFECT HAS BEEN
CANCELLED FOR SOUTHERN WISCONSIN. THE THREAT OF SEVERE WEATHER HAS
ENDED.

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

14 thunderstorm wind, 2 flood. Local standard time, as filed.

Thunderstorm Wind, Iowa

When: September 7, 5:45 PM CST to 5:55 PM CST
Where: Iowa County, Rewey
Measured: 56 kt (64 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 42.850, -90.400

Thunderstorm Wind, Lafayette

When: September 7, 5:45 PM CST to 5:58 PM CST
Where: Lafayette County, Benton
Measured: 56 kt (64 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 42.567, -90.383

Thunderstorm Wind, Sauk

When: September 7, 6:05 PM CST to 6:10 PM CST
Where: Sauk County, Lake Delton
Measured: 65 kt (75 mph)
Property damage: $75,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.583, -89.783

Thunderstorm Wind, Green

When: September 7, 6:10 PM CST
Where: Green County, Monroe
Measured: 52 kt (60 mph)
Reported by: GENERAL PUBLIC
Coordinates: 42.600, -89.633

Thunderstorm Wind, Dane

When: September 7, 6:10 PM CST to 6:15 PM CST
Where: Dane County, Madison
Measured: 50 kt (58 mph)
Reported by: NEWSPAPER
Coordinates: 43.067, -89.417

Thunderstorm Wind, Columbia

When: September 7, 6:20 PM CST
Where: Columbia County, Portage
Measured: 56 kt (64 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.550, -89.450

Thunderstorm Wind, Rock

When: September 7, 6:20 PM CST
Where: Rock County, 1 mi SW of Evansville
Measured: 56 kt (64 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 42.767, -89.317

Flood, Rock

When: September 7, 6:20 PM CST to 7:30 PM CST
Where: Rock County, Beloit
Reported by: LAW ENFORCEMENT
Coordinates: 42.671, -89.072 (the zone’s center; the record gives no point)

Thunderstorm Wind, Marquette

When: September 7, 6:25 PM CST to 6:30 PM CST
Where: Marquette County, Endeavor
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.700, -89.467

Thunderstorm Wind, Rock

When: September 7, 6:25 PM CST
Where: Rock County, Beloit
Measured: 56 kt (64 mph)
Property damage: $10,000
Reported by: NEWSPAPER
Coordinates: 42.517, -89.033

Thunderstorm Wind, Green Lake

When: September 7, 6:30 PM CST to 6:50 PM CST
Where: Green Lake County, 3 mi NE of Kingston
Measured: 56 kt (64 mph)
Reported by: EMERGENCY MANAGER
Coordinates: 43.733, -89.067

Thunderstorm Wind, Columbia

When: September 7, 6:55 PM CST
Where: Columbia County, 3 mi S of Cambria
Measured: 56 kt (64 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.500, -89.100

Thunderstorm Wind, Jefferson

When: September 7, 7:20 PM CST
Where: Jefferson County, 1 mi S of Palmyra
Measured: 52 kt (60 mph)
Reported by: NWS EMPLOYEE(OFF DUTY)
Coordinates: 42.867, -88.600

Thunderstorm Wind, Walworth

When: September 7, 7:30 PM CST to 7:45 PM CST
Where: Walworth County, Walworth
Measured: 56 kt (64 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 42.533, -88.600

Thunderstorm Wind, Waukesha

When: September 7, 7:40 PM CST
Where: Waukesha County, 1 mi SW of Oconomowoc
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.100, -88.500

Flood, Dane

When: September 7, 9:00 PM CST to 11:00 PM CST
Where: Dane County, Madison
Reported by: NEWSPAPER
Coordinates: 43.067, -89.418 (the zone’s center; the record gives no point)

What these are

Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Wisconsin in 2001 Every state in 2001 This day in weather history Warnings in Wisconsin, September 2001

Sources

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: 5269169, 5269170, 5269171, 5269174, 5269184, 5269172, 5269175, 5269176, 5269177, 5269182, 5269178, 5269173, 5269179, 5269180, 5269181, 5269183.