A slow moving low pressure system tracked across Wisconsin during the afternoon hours on Thursday (8/1). Showers and thunderstorms developed in a very moist airmass leading to small hail, gusty winds, and very heavy rain along across portions of central Wisconsin.
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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 GRB wrote it up.
A slow moving low pressure system tracked across Wisconsin during the afternoon hours on Thursday (8/1). Showers and thunderstorms developed in a very moist airmass leading to small hail, gusty winds, and very heavy rain along across portions of central Wisconsin. As much as 3 to 5 inches of rain fell across this region during the afternoon, causing flash flooding and road closures across portions of Marathon, Wood, and Waushara counties.
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 Green Bay, WI wrote its last area forecast discussion before the first event at Aug 1, 11:51 AM CST, 1 hour 29 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Green Bay WI 1251 PM CDT Thu Aug 1 2024 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - Thunderstorms are possible at times today and tonight. A few storms may become strong to severe this afternoon and evening. However, heavy rainfall and localized flooding will be the main concern. - Above normal temperatures are expected to continue through Saturday. A cold front will then move through the area Saturday night into Sunday morning, returning temperatures closer to normal early next week. - Storm chances will return at times from Saturday night through Tuesday. It is possible that a MCS moves across the southern half of Wisconsin Monday night and Tuesday. && .DISCUSSION... Issued at 334 AM CDT Thu Aug 1 2024 Short Term...Today...Tonight...and Friday An area of showers and thunderstorms across western Wisconsin will continue to weaken as it moves east towards central Wisconsin this morning. Additional showers and thunderstorms are expected this afternoon into this evening as a negatively tilted mid-level PV anomaly tracks southeast through Wisconsin. Some of these storms could be strong to severe as SBCAPEs will rise to around 2 J/g. Heavy rainfall is also possible as PWATs soar to 1.5 to 1.9 inches. Some Flash Flooding will be possible as one hour Flash Flood Guidance is only 1 to 2 inches today across central and east-central Wisconsin with the probability of reaching an inch in one hour at 30 to 50 percent under any thunderstorms that develop across this area this afternoon. Abundant cloud cover across the region will keep temperatures a bit cooler today, with highs in the lower to middle 80s, as dew points remain high from 66 to 71 degrees. Any thunderstorms should end later this evening as the aforementioned shortwave exits the region, with quiet weather and some patchy fog expected later tonight. Lows tonight will remain warm, mainly in the 60s. High pressure will build in across the upper Mississippi Valley on Friday, which should keep the area dry. Despite some MUCAPEs building to around 1 J/g on Friday afternoon, model soundings show a capping inversion in place across the western Great Lakes. Therefore, will keep precipitation out of the forecast. Highs on Friday are expected to soar back into the middle to upper 80s across the region. The warm temperatures, when combined with dew points near or around 70, will cause Heat Index values to rise to around 90 or the lower 90s across central, east-central, and northeast Wisconsin away from the lake. Long Term...Friday Night Through Wednesday 500mb ridge across the southwest United States with a deepening trough across eastern North America early next week will result in a west-northwest flow pattern. Above normal temperatures will continue on Saturday before temperatures return closer to normal during the first half of next week. For Friday night and Saturday, dry conditions are expected as high pressure prevails. Late in the day Saturday, a cold front will approach from the northwest. This feature is expected to move across the area Saturday night into Sunday, resulting in the chances of showers and storms. Timing of the front is not ideal for severe weather being late at night across northern Wisconsin, but will need to watch this feature in the next day or two. The front is expected to sag south of the area on Sunday. There is still enough instability around for a continued chance of showers and thunderstorms Sunday despite the front being to the south. Questions arise Sunday night into Monday on how far south the front will sink. The Canadian and GFS model sink the front far enough south late Sunday night into Monday to bring dry conditions to the area. The latest ECMWF also support this solution, thus confidence is growing for a dry period late Sunday night into Monday morning. The models diverge on the frontal position Monday night into Tuesday with the latest GFS model run keeping precipitation well south of the forecast area. The ECMWF and Canadian model are in better agreement with an MCS moving across the southern half of the state, although the Canadian and the ECMWF model have shifted a little further south tonight compared to last night. On Tuesday morning, any lingering showers and storms will exit the area as high pressure builds into the region Tuesday afternoon and Wednesday, resulting in mainly dry weather. && .AVIATION...for 18Z TAF Issuance Issued at 1250 PM CDT Thu Aug 1 2024 An upper level disturbance will move across Wisconsin today and bring scattered showers and thunderstorms this afternoon and evening. VFR ceilings are expected outside of any convective activity. Some clearing is possible late tonight, with mostly clear skies and good flying weather Thursday. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && DISCUSSION.....Kurimski/Eckberg AVIATION.......RDM
Hazardous Weather Outlook National Weather Service Green Bay WI 335 AM CDT Thu Aug 1 2024 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-020845- Vilas-Oneida-Forest-Florence-Northern Marinette County-Lincoln- Langlade-Menominee-Northern Oconto County-Door-Marathon-Shawano- Wood-Portage-Waupaca-Outagamie-Brown-Kewaunee-Waushara-Winnebago- Calumet-Manitowoc-Southern Marinette County- Southern Oconto County- 335 AM CDT Thu Aug 1 2024 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Today and Tonight Strong to severe storms will be possible this afternoon and evening, mainly along and south of Highway 29. Heavy rainfall and localized flooding will be the main concerns. A few storms could could contain damaging winds and hail. .DAYS TWO THROUGH SEVEN...Friday through Wednesday On and off storm chances return Saturday night through Tuesday. Stronger storms may be possible Monday night into Tuesday morning. .SPOTTER INFORMATION STATEMENT... Spotters are requested to report any instances of hail, wind gusts over 40 mph, and heavy rain/flooding through this evening. LMZ521-522-541>543-020845- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 335 AM CDT Thu Aug 1 2024 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Today and Tonight Thunderstorms will be possible at times this afternoon and evening. A few of the storms could contain strong gusty winds and hail. Waves may also be higher in and near thunderstorms. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Periodic storm chances then return Sunday through Tuesday. Any storms during this time may pose a threat to mariners. Kurimski/Eckberg
Special Weather Statement
National Weather Service Green Bay WI
917 AM CDT Thu Aug 1 2024
WIZ037-011445-
Waupaca WI-
917 AM CDT Thu Aug 1 2024
...A STRONG THUNDERSTORM WILL IMPACT WESTERN WAUPACA COUNTY THROUGH
945 AM CDT...
At 916 AM CDT, Doppler radar was tracking a strong thunderstorm over
Chain O' Lakes-King, or over Waupaca, moving north at 15 mph.
HAZARD...Wind gusts up to 40 mph. Brief, torrential rains.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Waupaca, Hartman Creek State Park, Chain O' Lakes-King, Weyauwega,
Manawa, Iola, King, Sheridan, Scandinavia, and Ogdensburg.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 4429 8923 4450 8923 4466 8918 4455 8881
4424 8901 4424 8906
TIME...MOT...LOC 1416Z 199DEG 14KT 4436 8913
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
RDMSpecial Weather Statement
National Weather Service Green Bay WI
1042 AM CDT Thu Aug 1 2024
WIZ031-037>039-049-011615-
Calumet WI-Waupaca WI-Shawano WI-Outagamie WI-Brown WI-
1042 AM CDT Thu Aug 1 2024
...THUNDERSTORMS WITH VERY HEAVY RAIN WILL IMPACT SOUTHWESTERN
BROWN...NORTHEASTERN CALUMET...NORTHEASTERN WAUPACA...OUTAGAMIE AND
CENTRAL SHAWANO COUNTIES THROUGH 1115 AM CDT...
At 1041 AM CDT, Doppler radar was tracking thunderstorms along a
line extending from 8 miles southeast of Clintonville to near
Brillion. Movement was north at 20 mph.
HAZARD...Very heavy rain and wind gusts up to 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Strong thunderstorms will be near...
Appleton, Kaukauna, Little Chute, Kimberly, Brillion, and Black
Creek around 1045 AM CDT.
Other locations impacted by these storms include Nichols, Mackville,
Leeman, Little Rapids, Morrison, Freedom, Wolf River Bottoms Wildlife
Area, Askeaton, Twelve Corners, and Five Corners.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 4409 8810 4449 8873 4476 8866 4431 8793
4424 8798 4424 8804 4416 8804
TIME...MOT...LOC 1541Z 188DEG 17KT 4451 8865 4413 8810
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
RDMSpecial Weather Statement
National Weather Service Green Bay WI
115 PM CDT Thu Aug 1 2024
WIZ030-035-011900-
Wood WI-Marathon WI-
115 PM CDT Thu Aug 1 2024
...STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN WOOD AND
SOUTHWESTERN MARATHON COUNTIES THROUGH 200 PM CDT...
At 114 PM CDT, Doppler radar was tracking a cluster of strong
thunderstorms over Marshfield, or 21 miles northeast of Neillsville,
moving north at 15 mph.
HAZARD...Wind gusts up to 40 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Marshfield and Spencer.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 4482 9026 4478 9007 4462 9014 4465 9032
4468 9032
TIME...MOT...LOC 1814Z 199DEG 12KT 4469 9020
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
MPCThe La Crosse radar (KARX), 124 km away, was scanning. The volume nearest the first event began at 19:21 UTC.
3 flash flood. Local standard time, as filed.
Heavy rain caused flash flooding along Highway 13 and County V in northwestern Wood County.
Heavy rain caused flash flooding in Schofield and Rothschild in central Marathon County. Many roads were closed due to standing and flowing water.
Heavy rain caused flash flooding and a road closure at County V and state route 21 in western Waushara County.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2024Every state in 2024This day in weather historyWarnings in Wisconsin, August 2024
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: 1200016, 1200017, 1200024.