A line of strong to severe thunderstorms moved northeast through southern Wisconsin. Short segments of the line managed to bow out and generate isolated downbursts.
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 line of strong to severe thunderstorms moved northeast through southern Wisconsin. Short segments of the line managed to bow out and generate isolated downbursts.
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 18, 2:00 PM CST, 5 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 300 PM CDT TUE SEP 18 2007 .DISCUSSION...FORECAST FOCUS ON AREAL COVERAGE AND TIMING OF CONVECTION TONIGHT AND RETURN OF WARM AIR AFTER MIDWEEK. .SHORT TERM...NGM/NAM/GFS/WRF PROGS ARE SLOWING APPROACH OF CONVECTION BY SEVERAL HOURS AS SURFACE COOL FRONT AND BULK OF ASSOCIATED CONVECTION CURRENTLY CONTINUE OVER MINNESOTA AND IOWA. AHEAD OF FRONT...UNIDIRECTIONAL SOUTHWEST FLOW AT ALL LEVELS INCLUDES 30 KNOT LOW LEVEL JET AND 850 MILLIBAR THERMAL TEMPERATURE RIDGE ALONG WITH MOISTURE AS DEW POINTS IN THE LOW 60S ALREADY IN PLACE OVER CWA. PREVIOUSLY PROGGED ISENTROPIC LIFT FOR OVERNIGHT HOURS IN NOW ABSENT AND CONDENSATION PRESSURE DEFICITS DROP TO JUST BELOW 50 AROUND 06Z WEDNESDAY TIME FRAME. PRECIPITATION EFFICIENCIES AROUND 06Z WEDNESDAY ALSO HAVE BEEN REDUCED TO AROUND 1.50 OVER SOUTH CENTRAL WISCONSIN AND THEN FALL OFF RAPIDLY BY 12Z WEDNESDAY. THE BEST SHORT WAVE ENERGY AND UPPER JET STRUCTURE IS STILL PROGGED TO PASS FROM IOWA INTO NORTHWEST WISCONSIN...BUT TAIL OF UPWARD MOTION OVER CWA SOMEWHAT REDUCED IN STRENGTH FROM PREVIOUS PROG RUNS. THIS IS CONFIRMED BY LOOP OF COLDEST CLOUD TOPS PROGGED BY CRAS IR SATELLITE LOOP. THUS DELAYING AND WEAKENING TREND OF CONVECTION DURING THE LATE OVERNIGHT HOURS FROM WEST TO EAST OVER CWA LOOKS REASONABLE. WILL KEEP HIGHEST RAIN CHANCES FOR WESTERN PORTIONS AND GO WITH LOWER RAIN CHANCE NUMBERS IN THE EAST. .LONG TERM...WEAK HIGH PRESSURE PASSES ACROSS AREA WEDNESDAY AND WEDNESDAY NIGHT WITH A SLIGHT COOL DOWN IN TEMPERATURES DUE TO SHALLOW IN NATURE OF FRONTAL BOUNDARY. THEN SURFACE SOUTHWEST FLOW QUICKLY RETURNS THURSDAY AND LASTS INTO FRIDAY WITH A GENERALLY DRY AND WARM PERIOD OF WEATHER EXPECTED. A SLIGHT COOL DOWN IN TEMPERATURES IS EXPECTED OVER THE WEEKEND. && .AVIATION...KMSN AND KMKE IN WARM SECTOR AHEAD OF TROF THAT IS WELL WEST OF THE AREA TODAY. CAPPED ENVIRONMENT WILL KEEP VFR CONDITIONS OVR SRN WI INTO THE EVENING. THE TROF AND ASSOC CDFNT REACH MKSN BTWN 06-09Z TONIGHT. BY THIS TIME THE FRONT HAS LOST MUCH OF THE LLV FORCING...THE MID LEVEL S/W HAS SHOT OFF TO THE NE...AND DIURNAL SUPPORT HAS FADED. KEEPING MKE DRY WITH THE FRONT...MORE IN LINE WITH GFS POPS AND GUID CIG CONSIDERATIONS. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && ZAJDEL/10
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 755 PM CDT TUE SEP 18 2007 WIZ046-047-051-052-056>060-062>072-190930- MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE- WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE- LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA- 755 PM CDT TUE SEP 18 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN. .DAY ONE...TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED THIS EVENING IN PARTS OF SOUTH CENTRAL WISCONSIN...WEST AND NORTHWEST OF MADISON. THESE THUNDERSTORMS COULD BECOME SEVERE. THE MAIN SEVERE WEATHER RISKS WOULD BE DAMAGING WINDS AND LARGE HAIL. THERE IS A CHANCE OF THUNDERSTORMS ACROSS THE REMAINDER OF THE AREA THROUGH THE NIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE IS A SLIGHT CHANCE OF THUNDERSTORMS MONDAY NIGHT ALONG AND NORTH OF A LINE FROM PORT WASHINGTON TO SPRING GREEN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. LMZ643>646-665-190930- 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- 755 PM CDT TUE SEP 18 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN. .DAY ONE...TONIGHT A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR SOUTHERLY WINDS GENERATING 3 TO 6 FOOT WAVES. THERE IS A CHANCE OF THUNDERSTORMS AFTER MIDNIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY WINDS AND WAVES MAY APPROACH SMALL CRAFT ADVISORY CRITERIA ON FRIDAY. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS MONDAY NIGHT NORTH OF PORT WASHINGTON. MBK WWW.WEATHER.GOV/MKX
The La Crosse radar (KARX), 91 km away, was scanning. The volume nearest the first event began at 01:28 UTC.
5 thunderstorm wind. Local standard time, as filed.
Powerful thunderstorm downburst winds gusting to an estimated 56 knots (65 mph) toppled several large trees. Tree branch debris knocked down some power lines.
Powerful thunderstorm downburst winds gusting to an estimated 56 knots (65 mph) toppled several large trees. Tree branch debris knocked down some power lines.
Powerful thunderstorm downburst winds gusting to an estimated 56 knots (65 mph) toppled several large trees. Tree branch debris knocked down some power lines.
Powerful thunderstorm downburst winds gusting to an estimated 56 knots (65 mph) toppled several large trees. Tree branch debris knocked down some power lines.
Powerful thunderstorm downburst winds gusting to an estimated 65 knots (75 mph) toppled several large trees. Tree branch debris knocked down some power lines. The winds lifted one side of a trained spotters's vehicle about 6 inches into the air.
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, September 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: 61084, 61085, 61086, 61087, 61088.