Alert archive / Wisconsin / Flash Flood Warnings in 2026
Flash Flood Warning 10, NWS Green Bay, WI
NWS Green Bay, WI issued this flash flood warning at Jul 1, 2026, 10:51 PM CDT for 4 counties in Wisconsin. It was in force for 3 hr. 4 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Jul 1, 2026, 10:51 PM CDT (03:51 UTC)
- Expired
- Jul 2, 2026, 1:45 AM CDT
- In force
- 3 hr
- Issued by
- NWS Green Bay, WI
- Area
- Storm-based polygon
- Flood severity
- None
Counties Brown County, WI, Calumet County, WI, Outagamie County, WI, Winnebago County, WI
The radar
The Green Bay radar (KGRB), 40 km from the middle of the area, began a volume at 03:52 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 1, 11:13 PM CDT | FLASH FLOOD | Appleton, WI | Several streets in Appleton are flooded. |
| Jul 1, 11:26 PM CDT | FLASH FLOOD | 1 E Kaukauna, WI | Report from mPING: Street/road flooding; Street/road closed; Vehicles stranded. |
| Jul 2, 12:01 AM CDT | FLASH FLOOD | Menasha, WI | Several streets were flooded. |
| Jul 2, 12:01 AM CDT | RAIN 2.75 | 2 Ne Darboy, WI |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
Did it verify
Verified. The Iowa Environmental Mesonet's Cow matched 3 storm reports to this flash flood warning; the first came 22 minutes after it went out.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The nearest sounding before it
Davenport, (KDVN), launched 00:00Z, 3.9 hours before the alert went out and 336 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1835 J/kg
- Mixed-layer CIN
- -23 J/kg
- Mixed-layer LCL
- 1365 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 58 m²/s²
- 0-3 km storm-relative helicity
- 133 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 3.5
The text
As transmitted.
489
WGUS53 KGRB 020351
FFWGRB
WIC009-015-087-139-020645-
/O.NEW.KGRB.FF.W.0010.260702T0351Z-260702T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Green Bay WI
1051 PM CDT Wed Jul 1 2026
The National Weather Service in Green Bay has issued a
* Flash Flood Warning for...
Northwestern Calumet County in east central Wisconsin...
Northeastern Winnebago County in east central Wisconsin...
Southwestern Brown County in northeastern Wisconsin...
Southeastern Outagamie County in northeastern Wisconsin...
* Until 145 AM CDT.
* At 1051 PM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 1.5 inches of rain
have fallen. Additional rainfall amounts of 1 to 2 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Appleton, Menasha, Kaukauna, Little Chute, Kimberly, Darboy,
Northern Lake Winnebago, Neenah, Greenville, Combined Locks,
Wrightstown, Holland and Uw Fox Valley.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4427 8863 4438 8816 4425 8813 4414 8860
4415 8859
FLASH FLOOD...RADAR INDICATED
$$
JLA2 follow-up statements
198
WGUS73 KGRB 020420
FFSGRB
Flash Flood Statement
National Weather Service Green Bay WI
1120 PM CDT Wed Jul 1 2026
WIC009-015-087-139-020645-
/O.CON.KGRB.FF.W.0010.000000T0000Z-260702T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Brown WI-Calumet WI-Outagamie WI-Winnebago WI-
1120 PM CDT Wed Jul 1 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 AM CDT THURSDAY
FOR NORTHWESTERN CALUMET, NORTHEASTERN WINNEBAGO, SOUTHWESTERN BROWN
AND SOUTHEASTERN OUTAGAMIE COUNTIES...
At 1120 PM CDT, local law enforcement reported thunderstorms
producing heavy rain across the warned area. Between 2 and 2.5 inches
of rain have fallen. Additional rainfall amounts of 1 to 2 inches are
possible in the warned area. Flash flooding is ongoing or expected to
begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Law enforcement reported.
IMPACT...Life threatening flash flooding of creeks and streams, urban
areas, highways, streets and underpasses.
Some locations that will experience flash flooding include...
Appleton, Menasha, Kaukauna, Little Chute, Kimberly, Darboy,
Northern Lake Winnebago, Neenah, Greenville, Combined Locks,
Wrightstown, Holland and Uw Fox Valley.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 4427 8863 4438 8816 4425 8813 4414 8860
4415 8859
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
JLA968
WGUS73 KGRB 020638
FFSGRB
Flash Flood Statement
National Weather Service Green Bay WI
138 AM CDT Thu Jul 2 2026
WIC009-015-087-139-020648-
/O.EXP.KGRB.FF.W.0010.000000T0000Z-260702T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Brown WI-Calumet WI-Outagamie WI-Winnebago WI-
138 AM CDT Thu Jul 2 2026
...FLASH FLOOD WARNING WILL EXPIRE AT 145 AM CDT EARLY THIS MORNING
FOR NORTHWESTERN CALUMET, NORTHEASTERN WINNEBAGO, SOUTHWESTERN BROWN
AND SOUTHEASTERN OUTAGAMIE COUNTIES...
Flash Flooding is no longer expected to pose a threat. However, a
Flood Advisory remains in effect for the area until 4 am. Please
continue to heed remaining road closures.
A Flood Watch remains in effect until 1000 AM CDT Thursday for
portions of central, east central, and northeast Wisconsin.
&&
LAT...LON 4427 8863 4438 8816 4425 8813 4414 8860
4415 8859
$$
KurimskiWhat forecasters said that day
The local office's own words before this flash flood warning went out, 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 this flash flood warning went out at Jul 1, 6:35 PM CDT, 4 hours 16 minutes earlier. Its key messages:
- A Heat Advisory is in effect until 8 PM today for east-central and far northeast Wisconsin, including the lakeshore counties. Additional heat headlines may be needed Thursday.
- Chance for severe weather late this afternoon into tonight with potential for damaging straight-line wind gusts, large hail, and isolated tornadoes. Isolated flash flooding is also possible.
- Additional chances for thunderstorms through the holiday weekend.
Area forecast discussion, Jul 1, 6:35 PM CDT, 4 hours 16 minutes before
Area Forecast Discussion National Weather Service Green Bay WI 635 PM CDT Wed Jul 1 2026 Updated aviation portion for 00Z TAF issuance .KEY MESSAGES... - A Heat Advisory is in effect until 8 PM today for east-central and far northeast Wisconsin, including the lakeshore counties. Additional heat headlines may be needed Thursday. - Chance for severe weather late this afternoon into tonight with potential for damaging straight-line wind gusts, large hail, and isolated tornadoes. Isolated flash flooding is also possible. - Additional chances for thunderstorms through the holiday weekend. && .DISCUSSION... Issued at 249 PM CDT Wed Jul 1 2026 Morning and early convection has largely shifted to the east as of 2PM. Expect a lull in thunderstorm activity across the forecast area over the next 4-6 hours before the next round of thunderstorms begins to develop and move into central and east-central WI. This round of thunderstorms is expected to be focused along a nearly stationary boundary that that extended from near Green Bay back toward La Crosse and then toward central IA. A mid-level short-wave is also evident on water-vapor imagery over western IA and southern MN. As this short-waves moves east it will be overspreading a highly unstable environment with dew points in the low to middle 70s and temperatures quickly warming through the 80s. At 500mb the region is located under the right rear quad of an 80kt jet streak resulting in 0-6 shear of 40-50kts. This creates a favorable parameter space for strong to severe thunderstorms capable of producing damaging wind gusts, large hail, and possible tornados. The tornado threat is conditional on any storms remain discreet for a period this evening. As storms grow upscale this may transition a damaging wind event with 60-80mph wind gusts possible. The window for these higher end severe hazards is 7PM to midnight. 18Z HRRR also shows convection reinvigorate overnight as a LLJ noises into central and east-central WI. This round of storms is very conditional on where this evenings convection shifts the stationary boundary. If storms do develop there would be a marginal threat for severe winds and hail. In addition to the multiple rounds of storms this evening and overnight, there will is a flooding threat given deep warm cloud depths and PWATs around 2 inches during times of convection. The flash flood threat is also conditional on training storms as storms are expected to be moving quickly to the east, especially if they develop into a bowing complex. Models indicate additional convection may develop on Thursday, however this will depend greatly on the evolution of today/tonight's convection and where outflow boundaries reside. Latest guidance would suggest convection developing somewhere from central WI to southern WI during Thursday afternoon, likely along the instability gradient. If the strong to severe storms end up in our forecast area, damaging winds would be the main threat. The next chance for widespread showers and storms appears to be on Friday with the passage of the first of multiple mid-level shortwaves throughout the 4th of July holiday weekend. Timing and intensity of storms related to this short-wave are highly uncertain. However, one signal that is persistent for Friday in a round of heavy rainfall across central and east-central WI as the region remains under a very humid air mass. Additional rounds of thunderstorms are possible on Saturday and Sunday, however, however, given the volatile nature of this air mass it predictability with any details at this time is low. Beyond Sunday global ensembles and ML models do trend toward a drier period through the first half of next week. Heat/Temperatures...Heat Advisory for central and east-central WI remains in effect until 8 PM this evening as clearing skies are quickly leading to rapid warming with temperatures in the low to middle 80s and heat indices in the middle to upper 90s. A few spots may near 100 degree heat indices again on Thursday, but will again depend on thunderstorm activity. For Friday through the holiday weekend, temperatures and dew points look to slightly decrease, but will continue to monitor the need for additional heat headlines. && .AVIATION...for 00Z TAF Issuance Issued at 635 PM CDT Wed Jul 1 2026 Active weather will be the main aviation concern for the early TAF period through the overnight. Strong to possibly severe thunderstorms are expected to develop to our west and make their way into the region through the early evening. Included a prevailing TSRA group for the best timing of the arrival of storms, but would expect some rain behind the initial line of storms. Strongest storms will be capable of producing damaging wind gusts up to 70 mph, large hail, and isolated tornadoes. Ending time of active weather remains uncertain, as recent guidance does suggest the potential for continued rain or a second round early Thursday morning, so kept this mention in the current TAFs. Finally, another round of thunderstorms will be possible Thursday PM, with the strongest storms expected south of a CWA to GRB line. Amendments will be needed as this severe weather day progresses given the volatile pattern. Ahead of these stronger storms inbound from the west at the beginning of the period, a couple weaker storms are possible for ATW and MTW as suggested by recent satellite and radar trends around the TAF issuance. Added a brief TEMPO and PROB 30 for these areas. As the showers and storms come to an end sometime late tonight or towards the end of the TAF period, there are signs of fog development across north-central WI with MVFR/IFR cigs. && .GRB WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM CDT this evening for WIZ020>022-031- 037>040-045-048>050-073-074. Flood Watch through Thursday morning for WIZ020-030-031-035>040- 045-048>050-074. && DISCUSSION.....GK AVIATION.......Uhlmann
Hazardous weather outlook, Jul 1, 2:52 PM CDT, 7 hours 59 minutes before
Hazardous Weather Outlook National Weather Service Green Bay WI 252 PM CDT Wed Jul 1 2026 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-022000- 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- 252 PM CDT Wed Jul 1 2026 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Tonight Heat Advisories for east-central and far northeast Wisconsin, including the lakeshore areas is in effect until 8 PM today, where heat index values up to 100 degrees are forecast. Multiple rounds of thunderstorms are expected late this afternoon into tonight and may result in a higher-end severe risk with the potential for damaging straight-line winds over 70 mph, hail up to golf-ball size, and isolated tornadoes. Isolated flash flooding is also possible. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday Daytime heat index values will be near 100 degrees on Thursday, especially over east-central Wisconsin. A Heat Advisory may be needed. Periodic chances for thunderstorms will continue through the holiday weekend. A few storms on Thursday could be strong to severe. Heavy rain could also occur. .SPOTTER INFORMATION STATEMENT... Spotters are requested to report peak wind gusts, hail, and any flooding to the National Weather Service in Green Bay. Spotter activation may be needed on Thursday. LMZ521-522-541>543-022000- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 252 PM CDT Wed Jul 1 2026 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight There is a chance for thunderstorms through tonight. Some storms may become severe with damaging straight-line wind gusts and large hail. Any thunderstorm would pose a hazard to mariners. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday Periodic chances for thunderstorms will continue through the holiday weekend. Storms occurring Thursday could be strong to severe. Any thunderstorm would pose a hazard to mariners. GK
In the hours before
Local storm report, Jul 1, 5:34 PM CDT, 5 hours 17 minutes before
Preliminary Local Storm Report
National Weather Service Green Bay WI
534 PM CDT Wed Jul 1 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0812 AM Tstm Wnd Dmg 2 SE Anston 44.60N 88.14W
07/01/2026 Brown WI Public
Western portion of Village of Howard. Many
large trees uprooted. Willow tree collapsed.
Time estimated from radar.
&&Special weather statement, Jul 1, 7:26 PM CDT, 3 hours 25 minutes before
Special Weather Statement
National Weather Service Green Bay WI
726 PM CDT Wed Jul 1 2026
WIZ050-020045-
Manitowoc WI-
726 PM CDT Wed Jul 1 2026
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN MANITOWOC COUNTY
THROUGH 745 PM CDT...
At 726 PM CDT, Doppler radar was tracking a strong thunderstorm near
Two Creeks, or 9 miles north of Manitowoc, moving east at 40 mph.
HAZARD...Wind gusts up to 30 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.
This strong thunderstorm will be near...
Two Creeks around 730 PM CDT.
Other locations impacted by this storm include Mishicot, Fisherville,
Larrabee, Point Beach Nuclear Plant, Shoto, Francis Creek, and Two
Rivers.
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 4427 8775 4435 8748 4431 8748 4416 8753
4416 8770
TIME...MOT...LOC 0026Z 256DEG 34KT 4423 8766
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH
EckbergSpecial weather statement, Jul 1, 9:05 PM CDT, 1 hour 46 minutes before
Special Weather Statement
National Weather Service Green Bay WI
905 PM CDT Wed Jul 1 2026
WIZ035>037-045-020300-
Waupaca WI-Portage WI-Wood WI-Waushara WI-
905 PM CDT Wed Jul 1 2026
...AN AREA OF STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN
WAUSHARA...SOUTHERN PORTAGE...SOUTHWESTERN WAUPACA AND WOOD COUNTIES
UNTIL 10 PM CDT...
At 905 PM CDT, Doppler radar was tracking an area of strong
thunderstorms extending from over Plainfield to 32 miles southwest of
Spencer, or extending from 12 miles northwest of Wautoma to 44 miles
west of Wisconsin Rapids, moving east at 35 mph.
HAZARD...Half inch size hail.
SOURCE...Radar indicated.
IMPACT...Minor damage to outdoor objects is possible.
The strong thunderstorms will be near...
Plainfield around 905 PM CDT. Babcock around 915 PM CDT. Pittsville
and Wisconsin Rapids around 935 PM CDT. Chain O' Lakes-King, Lake
Wazeecha and Waupaca around 940 PM CDT. Hartman Creek State Park
around 945 PM CDT. Amherst, Whiting and Stevens Point around 955 PM
CDT.
Other locations impacted by these strong thunderstorms include
Hancock, Sandhill Wildlife Area, Heffron, Almond, Cranmoor, Scranton,
Dexterville, Veedum, Nekoosa and Walker.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Monitor the weather situation closely and be alert for threatening
weather conditions.
Torrential rainfall is also occurring with these storms and may lead
to flash flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 4461 9032 4440 8893 4400 8957 4401 8960
4425 8960 4425 9032
TIME...MOT...LOC 0204Z 249DEG 31KT 4420 8946 4421 9007 4440 9072
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...<30 MPH
JLASpecial weather statement, Jul 1, 10:21 PM CDT, 30 minutes before
Special Weather Statement
National Weather Service Green Bay WI
1021 PM CDT Wed Jul 1 2026
WIZ038-039-048>050-020400-
Calumet WI-Brown WI-Manitowoc WI-Winnebago WI-Outagamie WI-
1021 PM CDT Wed Jul 1 2026
...A LINE OF STRONG THUNDERSTORMS WILL IMPACT NORTHERN CALUMET...
NORTHEASTERN WINNEBAGO...SOUTHEASTERN OUTAGAMIE...NORTHWESTERN
MANITOWOC AND BROWN COUNTIES UNTIL 11 PM CDT...
At 1021 PM CDT, Doppler radar was tracking a line of strong
thunderstorms extending from 8 miles southwest of Green Bay to 7
miles southwest of Menasha, or extending from 8 miles southwest of
Green Bay to 10 miles north of Oshkosh, moving east at 30 mph.
HAZARD...Wind gusts up to 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
The strong thunderstorm will be near...
Appleton, Menasha, Kaukauna, Little Chute, Kimberly, Darboy,
Northern Lake Winnebago, High Cliff State Park and Brillion around
1025 PM CDT. Bellevue around 1030 PM CDT.
Other locations impacted by this strong thunderstorm include De Pere,
Greenleaf, Holland, Askeaton, Neenah, Dundas, Ledgeview, Allouez,
Lambeau Field and Greenville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Monitor the weather situation closely and be alert for threatening
weather conditions.
&&
LAT...LON 4407 8874 4436 8858 4455 8822 4466 8776
4459 8776 4443 8777 4422 8777
TIME...MOT...LOC 0320Z 249DEG 24KT 4442 8810 4426 8816 4417 8855
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
KurimskiThe office that day
Everything else NWS Green Bay, WI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 7:26 PM CDT | Special Weather Statement | GRB | Manitowoc | 19 min |
| Jul 1, 9:05 PM CDT | Special Weather Statement | GRB | Portage, Wood | 55 min |
| Jul 1, 10:12 PM CDT | Areal Flood Advisory | GRB | Brown, Calumet, Kewaunee, Outagamie, Portage, Waupaca and 3 more | 6 hr |
| Jul 1, 10:21 PM CDT | Special Weather Statement | GRB | Brown, Outagamie, Winnebago | 39 min |
| Jul 1, 10:48 PM CDT | Special Marine Warning | GRB | 90 min | |
| Jul 1, 10:58 PM CDT | Severe Thunderstorm Warning | GRB | Portage, Waushara | 47 min |
| Jul 1, 11:26 PM CDT | Flash Flood Warning | GRB | Portage, Waupaca, Waushara, Wood | 3 hr |
| Jul 1, 11:37 PM CDT | Severe Thunderstorm Warning | GRB | Waushara | 26 min |
| Jul 1, 11:58 PM CDT | Severe Thunderstorm Warning | GRB | Calumet, Winnebago | 42 min |
| Jul 2, 12:03 AM CDT | Areal Flood Advisory | GRB | Brown, Calumet, Kewaunee, Manitowoc, Winnebago | 4 hr |
| Jul 2, 1:02 AM CDT | Areal Flood Advisory | GRB | Brown, Marathon, Menominee, Oconto, Outagamie, Portage and 3 more | 3 hr |
Nearby
Flash Flood Warnings in Wisconsin, 2026Every flash flood warning in 2026
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.