An upper level disturbance and nearby stationary front led to multiple rounds of severe thunderstorms across southern WI. Large hail and damaging straight line winds led to trees down and some structural damage.
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.
An upper level disturbance and nearby stationary front led to multiple rounds of severe thunderstorms across southern WI. Large hail and damaging straight line winds led to trees down and some structural damage.
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 16, 9:51 AM CST, 1 hour 14 minutes earlier. Its key messages:
Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 1051 AM CDT Sat Aug 16 2025 .KEY MESSAGES... - Current thinking is that we will see scattered storm development between now 3 PM, then more widespread storms during the late afternoon and evening. - Multiple rounds of showers and thunderstorms are likely into early next week. Locally heavy rainfall is possible. There remains a lot of uncertainty with storm placement and timing over the next few days. - The rain over the next few days could lead to river rises again, with the potential for a few locations to return to at least minor flood stage. - Heat and humidity briefly returns today, especially across the southern portions of the area. - Drying out and becoming less humid by mid to late next week. && .UPDATE... Issued 1050 AM CDT Sat Aug 16 2025 The MCS tracking across central WI is showing additional development along the outflow on the southern edge as it nears Wautoma. Meanwhile, a remnant north-south boundary that stalled over far southwest WI and northeast IA late last night showed a few signs of lighting up with convection around 730 this morning, but that was quickly squashed by warm air advection aloft and a cap building in. That n-s boundary is expected to keep drifting eastward into south central WI today. As that west- east outflow boundary that is over central WI tracks southward and intersects with the n-s boundary (aka effective warm front) this afternoon, that will be a focus for more widespread convection. The cap should we weaker with time today. So our current thinking is that we will see scattered storm development between now 3 PM, then more widespread storms during the late afternoon and evening. With precipitable water values up to 2 inches, thinking that if the boundary sets up over southern WI, we have a potential for heavy rain and flooding tonight. We are considering a flood watch for southern WI, but still coordinating with neighboring offices and WPC. Cronce && .SHORT TERM... Issued 240 AM CDT Fri Aug 15 2025 Today through Sunday: Uncertainty surrounds todays forecast primarily as it relates to models not really handling ongoing overnight convection in the region whatsoever so it becomes difficult to trust anything models are showing later today. However, if there is something to be gleaned it is that models, though differing in timing, continue to show an MCS feature developing west of the Twin Cities area and and following the forward propagating corfidi vectors ESE. Southern WI may only see the southern end of this MCS swing through parts of the area. Central WI will see the best chances but with the propagation ESE the Milwaukee area is in play. In addition, given the layout of the upper level shortwave we should expect some development behind the MCS from the trailing MCV perhaps even developing another MCS in its wake, somewhat dependent on destabilization. Some CAMs support this idea but at the very least some storm activity should be expected based on trends in the CAMs. With PWATs consistently around 1.75 to 2+ inches through today heavy rainfall is likely with any storms with some limited training convection possible with the secondary storms behind the initial MCS. There is some severe risk as well with storms given the instability and decent deep layer shear with primary risks being damaging winds but we cannot rule out hail up to 1 inch. Then focus turns toward exactly where the effective warm front sets up tomorrow evening, likely impacted to a large degree by any outflow boundaries from afternoon and early evening convection. Where this sets up will become the focus for training storms this evening and overnight. A northwest to southeast oriented front, developing LLJ features, plenty of instability and SE oriented forward propagating corfidi vectors sets up the potential for several hours of training convection. Depending on exactly where this sets up bring risks for high rain amounts in a very short period with flash flooding possible. It is worth mentioning that highs will reach near 90 degrees today in southern portions of the CWA with humid conditions leading to apparent temps near the WI/IL border approaching 100 degree heat indices. We do not expect to issue a heat advisory but near heat advisory conditions are possible. Into Sunday, uncertainty remains high with the forecast especially since it will depend in large part on how today and tonight play out. Models suggest chances may continue into Sunday morning before forcing from the LLJ and upper level shortwave features weaken gradually allowing for things to die out. This seems to be the most probable scenario based on model trends. This also largely keeps during the day Sunday on the drier side with limited chances overall, especially into the afternoon, but with this being a limited predictability period any small changes in the forcing Sunday could yield storms as instability remains high over the region. Kuroski && .LONG TERM... Issued 240 AM CDT Fri Aug 15 2025 Sunday night through Friday: The active period of weather should continue Sunday night into early next week, though the timing and placement of features each day/night will depend on the previous day/night's activity. Models seem to be coming into slightly better agreement with low pressure developing in southern Minnesota Sunday night and shifting slowly east across central Wisconsin and weakening on Monday. The low track will bring a warm front northward through the area Monday, with a cold front pushing through later Monday into Monday evening. The low level jet nose may focus more in central and northern Wisconsin Sunday night, which may take more of the thunderstorm activity in that direction. Still, the warm and cold frontal passages would still bring chances for showers and storms through Monday evening. If any sunshine can develop ahead of the cold front, some stronger storms could occur. Will see if this trend with the low track and low level jet in the models holds. For now, will maintain 20 to 50 percent chances for showers and storms in the forecast. The concern for heavy rainfall remains, as bulk shear vectors will be parallel to the stationary/warm front and low level jet nose areas. Precipitable water values will be approaching or over 2.00 inches during this period, with warm cloud processes helping to produce the heavy rainfall potential. Temperatures will remain uncertain as well Sunday night into Monday night, depending on the low track, frontal boundary locations and clouds/precipitation. There may finally be a break by Tuesday which lingers into the rest of the week, as high pressure may build into the region from the north and northeast. This may usher in less humid conditions. Wood && .AVIATION... Issued 1050 AM CDT Sat Aug 16 2025 VFR conditions are expected to prevail through late afternoon. There are some lower ceilings around 3500 ft developing near MSN with the increasing low level moisture. Scattered showers and a few thunderstorms will be possible through mid afternoon. Then we are thinking that more widespread showers and thunderstorms will set up over southern WI in the late afternoon and linger through much of tonight. MVFR and lower is expected with the more widespread area of storms. Low ceilings should linger into mid morning hours but then diminish. Cronce && .MARINE... Issued 240 AM CDT Fri Aug 15 2025 Low pressure will move across Hudson Bay this morning and across northern Quebec later today. This will bring a front across the northern Great Lakes region today and will be a focus for thunderstorm development into early next week. These multiple rounds of thunderstorms could produce gusty winds as they roll through. South winds may linger into Saturday evening, then shift north to northeast Sunday and generally easterly early next week. The front will gradually move south of Lake Michigan by the middle of next week. Kuroski && .HYDROLOGY... Issued 911 PM CDT Fri Aug 15 2025 One Flood Warning and one Flood Watch remain in effect in the Milwaukee metro area, in the wake of the heavy rainfall this past weekend. The Lower Fox River at Waukesha remains in minor flood stage at this time, but will continue to decrease in stage height. It may remain in flood stage until at least early Sunday morning. The Fox River at New Munster may reach minor flood stage early next week, and is being monitored with a Flood Watch. Ponding of water in areas immediately near each river segment will remain possible until each can fall below flood stage by later this week. Continue to heed any road closures in all impacted areas until river stages recede further and Flood Warnings are allowed to expire. There is potential for localized heavy rainfall again this upcoming weekend, and area rivers (particularly in the Milwaukee metro area and surrounding counties) will be monitored for potential rises. DDV/Wood && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && Visit us at weather.gov/milwaukee Follow us on Facebook, X, and YouTube at: www.facebook.com/NWSMilwaukee www.x.com/NWSMilwaukee www.youtube.com/NWSMilwaukee
Hazardous Weather Outlook National Weather Service Milwaukee/Sullivan WI 332 AM CDT Sat Aug 16 2025 WIZ046-047-051-052-056>060-062>072-170845- Marquette-Green Lake-Fond du Lac-Sheboygan-Sauk-Columbia-Dodge- Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee- Lafayette-Green-Rock-Walworth-Racine-Kenosha- 332 AM CDT Sat Aug 16 2025 This Hazardous Weather Outlook is for portions of east central Wisconsin, south central Wisconsin and southeast Wisconsin. .DAY ONE...Today and Tonight The Fox River in Waukesha will remain above flood stage. There are chances for thunderstorms later this morning through tonight with the main risk being heavy rain and even slight chances for flash flooding. Hot and humid conditions expected for parts of southern Wisconsin today. .DAYS TWO THROUGH SEVEN...Sunday through Friday The Fox River in Waukesha will remain above flood stage until at least early Sunday morning. There will be continued chances for thunderstorms through the first half of next week. Locally heavy rainfall is possible, particularly in locations experiencing repeated rounds of storms. .SPOTTER INFORMATION STATEMENT... CoCoRAHS rainfall reports will be appreciated through next week. LMZ643>646-170845- 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- 332 AM CDT Sat Aug 16 2025 This Hazardous Weather Outlook is for the nearshore waters from Sheboygan Wisconsin to Winthrop Harbor Illinois. .DAY ONE...Today and Tonight There are chances for thunderstorms this morning into the overnight hours. Gusty winds are the main hazards. .DAYS TWO THROUGH SEVEN...Sunday through Friday There will be continued chances for thunderstorms through the first half of next week. LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868- 870-872-874-876-878-170845- Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to mid-line of lake.- Lake Michigan from Seul Choix Point to Rock Island Passage 5NM offshore to Mid Lake- Lake Michigan South of a line from Seul Choix Point to the Mackinac Bridge and North of a line from Charlevoix MI to South Fox Island 5NM offshore- Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to mid lake- Lake Michigan from Point Betsie to Manistee MI 5NM offshore to Mid Lake- Lake Michigan from Rock Island Passage to Sturgeon Bay WI 5NM offshore to mid lake- Lake Michigan from Sturgeon Bay to Two Rivers WI 5NM offshore to Mid Lake- Lake Michigan from Two Rivers to Sheboygan WI 5NM offshore to Mid Lake- Lake Michigan from Sheboygan to Port Washington WI 5NM offshore to Mid Lake- Lake Michigan from Port Washington to North Point Light WI 5NM offshore to Mid Lake- Lake Michigan from North Point Light to Wind Point WI 5NM offshore to Mid Lake- Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM offshore to Mid Lake- Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM offshore to Mid Lake- Lake Michigan from Wilmette Harbor to Michigan City in 5NM offshore to Mid Lake- Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid Lake- Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid Lake- Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to Mid Lake- Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid Lake- Lake Michigan from South Haven to Holland MI 5NM offshore to Mid lake- Lake Michigan from St Joseph to South Haven MI 5NM offshore to Mid Lake- 332 AM CDT Sat Aug 16 2025 This Hazardous Weather Outlook is for the open waters of Lake Michigan. .DAY ONE...Today and Tonight There are chances for thunderstorms this morning into the overnight hours. Gusty winds are the main hazards. .DAYS TWO THROUGH SEVEN...Sunday through Friday There will be continued chances for thunderstorms through the first half of next week. www.weather.gov/mkx
Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
1121 AM CDT Sat Aug 16 2025
WIZ046-047-051-057-161700-
Columbia WI-Green Lake WI-Marquette WI-Fond Du Lac WI-
1121 AM CDT Sat Aug 16 2025
...STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN FOND DU LAC...GREEN
LAKE...NORTHEASTERN COLUMBIA AND MARQUETTE COUNTIES THROUGH NOON
CDT...
At 1121 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Lake Poygan to near Princeton to 8 miles
northeast of Wisconsin Dells. Movement was southeast at 40 mph.
HAZARD...Wind gusts up to 50 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Portage, Ripon, Berlin, Montello, Markesan, Westfield, Princeton,
Rosendale, Green Lake, Brandon, Southern Lake Winnebago, Lawrence,
Eldorado, Packwaukee, Alto, Manchester, Mecan, Oxford, Endeavor, and
Neshkoro.
This includes the following highways...
Interstate 39 between mile markers 90 and 119.
Interstate 41 between mile markers 103 and 109.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4398 8889 4390 8888 4389 8841 4394 8840
4394 8830 4363 8885 4363 8900 4360 8901
4355 8949 4364 8960 4398 8960
TIME...MOT...LOC 1621Z 314DEG 34KT 4412 8887 4383 8919 4369 8964
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH
HEERENThe Green Bay radar (KGRB), 86 km away, was scanning. The volume nearest the first event began at 17:06 UTC.
13 hail, 11 thunderstorm wind. Local standard time, as filed.
Measured wind gust of 58 mph at ASOS station KFLD at Fond Du Lac Airport.
Ping pong ball hail on the west side of Janesville.
Tree damage across Janesville.
Public Facebook report via video of many hailstones shredding leaves off a backyard tree.
Image of ping-pong ball sized hail.
Personal weather station recording 59 mph wind gust.
Large branches down and corn bent over.
Multiple reports from the Dalton area of tree and power lines down. Some structural damage to a lumberyard and gun club including signs and poles down.
Large tree uprooted along Highway 16 in Portage. A branch down in the city.
A few tree limbs down on campsites near Pardeeville.
A large branch down.
Roof blown off a shed and paneling pulled away from the side of the shed. The sheet metal was blown about 200 ft away. Soybean crop also damaged.
A fallen large tree knocked down two other trees on the north shore of Fox Lake.
Trees and power lines down in Beaver Dam.
Public report of nickel sized hail measured with a ruler.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2025Every state in 2025This day in weather historyWarnings in Wisconsin, August 2025
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: 1290675, 1290630, 1290631, 1290639, 1290641, 1290676, 1290643, 1290645, 1290646, 1290648, 1290651, 1291213, 1291214, 1291206, 1291204, 1291207, 1291208, 1291205, 1291212, 1291209, 1291211, 1291210, 1290659, 1290663.