Alert archive / Wisconsin / Flash Flood Warnings in 2026
Flash Flood Warning 12, NWS Green Bay, WI
NWS Green Bay, WI issued this flash flood warning at Jul 8, 2026, 4:20 PM CDT for Brown County, Wisconsin. It was in force for 3 hr. 7 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 8, 2026, 4:20 PM CDT (21:20 UTC)
- Expired
- Jul 8, 2026, 6:50 PM CDT
- In force
- 3 hr
- Issued by
- NWS Green Bay, WI
- Area
- Storm-based polygon
- Flood severity
- None
County Brown County, WI
The radar
The Green Bay radar (KGRB), 9 km from the middle of the area, began a volume at 21:21 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 8, 4:34 PM CDT | FLASH FLOOD | 900 Suburban Dr De Pere, WI | Road flooding. |
| Jul 8, 4:44 PM CDT | FLASH FLOOD | Ashwaubenon, WI | Corrects previous flash flood report from Ashwaubenon ALLIED ST & CENTENNIAL ST. Flooded road ways. |
| Jul 8, 4:44 PM CDT | FLASH FLOOD | Ashwaubenon Allied St, WI | Flooded road ways. |
| Jul 8, 4:44 PM CDT | RAIN 2.1 | 3 Se De Pere, WI | 2.10 inches of rain fell in 25 minutes. |
| Jul 8, 4:45 PM CDT | FLASH FLOOD | De Pere, WI | some area roads in east de pere were reported to have a foot of rain standing on them. A few drains were also reported to be backing up. |
| Jul 8, 4:45 PM CDT | FLASH FLOOD | De Pere, WI | Some area roads in east De Pere were reported to have a foot of rain standing on them. A few drains were also reported to be backing up. |
| Jul 8, 4:50 PM CDT | FLASH FLOOD | 2 W Ashwaubenon, 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 6 storm reports to this flash flood warning; the first came 14 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
Detroit, MI (KDTX), launched 12:00Z, 9.3 hours before the alert went out and 416 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
- 48 J/kg
- Mixed-layer CIN
- -26 J/kg
- Mixed-layer LCL
- 779 m above ground
- 0-6 km bulk shear
- 7 kt
- 0-1 km storm-relative helicity
- 12 m²/s²
- 0-3 km storm-relative helicity
- 12 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
361
WGUS53 KGRB 082120
FFWGRB
WIC009-090015-
/O.NEW.KGRB.FF.W.0012.260708T2120Z-260709T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Green Bay WI
420 PM CDT Wed Jul 8 2026
The National Weather Service in Green Bay has issued a
* Flash Flood Warning for...
Central Brown County in northeastern Wisconsin...
* Until 715 PM CDT.
* At 420 PM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. The expected rainfall rate is 1
to 2 inches in 1 hour. 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...
Green Bay, Bellevue Town, Oneida, De Pere, Ashwaubenon, Bellevue,
Allouez, Ledgeview, Hobart, Humboldt, Glenmore, Langes Corners,
Poland and Little Rapids.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 4450 8819 4450 8776 4437 8777 4435 8819
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
JLA2 follow-up statements
548
WGUS73 KGRB 082159
FFSGRB
Flash Flood Statement
National Weather Service Green Bay WI
459 PM CDT Wed Jul 8 2026
WIC009-090015-
/O.CON.KGRB.FF.W.0012.000000T0000Z-260709T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Brown WI-
459 PM CDT Wed Jul 8 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 715 PM CDT THIS
EVENING FOR CENTRAL BROWN COUNTY...
At 459 PM CDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between
1.5 and 2.5 inches of rain have fallen. Flash flooding is already
occurring.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar and automated gauges.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Green Bay, Bellevue Town, Oneida, De Pere, Ashwaubenon, Bellevue,
Allouez, Ledgeview, Hobart, Humboldt, Glenmore, Langes Corners,
Poland and Little Rapids.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 4450 8819 4450 8776 4437 8777 4435 8819
FLASH FLOOD...RADAR AND GAUGE INDICATED
$$
JLA347 WGUS73 KGRB 082350 FFSGRB Flash Flood Statement National Weather Service Green Bay WI 650 PM CDT Wed Jul 8 2026 WIC009-090000- /O.CAN.KGRB.FF.W.0012.000000T0000Z-260709T0015Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Brown WI- 650 PM CDT Wed Jul 8 2026 ...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL BROWN COUNTY... Flood waters have receded. Significant flooding is no longer expected to pose a threat, though minor flooding may still occur in poor drainage and low-lying areas. Please continue to heed remaining road closures. && LAT...LON 4450 8819 4450 8776 4437 8777 4435 8819 $$ JLA
What 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 8, 1:13 PM CDT, 3 hours 7 minutes earlier. Its key messages:
- Scattered strong to severe thunderstorms remain expected this afternoon and evening, mainly between 3 and 8 PM over central and east-central Wisconsin. Damaging winds are the primary threat.
- Torrential rainfall rates of 2 to 3 inches per hour within the strongest storms will create a risk for localized flash flooding, especially in urban, low-lying, and poorly drained areas.
- Trends continue to be monitored for the excessive heat potential early next week.
Area forecast discussion, Jul 8, 1:13 PM CDT, 3 hours 7 minutes before
Area Forecast Discussion National Weather Service Green Bay WI 113 PM CDT Wed Jul 8 2026 Forecast discussion for routine afternoon forecast issuance .KEY MESSAGES... - Scattered strong to severe thunderstorms remain expected this afternoon and evening, mainly between 3 and 8 PM over central and east-central Wisconsin. Damaging winds are the primary threat. - Torrential rainfall rates of 2 to 3 inches per hour within the strongest storms will create a risk for localized flash flooding, especially in urban, low-lying, and poorly drained areas. - Trends continue to be monitored for the excessive heat potential early next week. && .DISCUSSION... Issued at 112 PM CDT Wed Jul 8 2026 The latest RAP analysis and satellite/radar imagery show a cold front stretching from west-central to north-central Wisconsin early this afternoon. Morning showers and storms have exited over northern Lake Michigan, giving way to partial clearing across central and east-central Wisconsin where temperatures have warmed into the lower 80s. Cooler temperatures in the lower to middle 70s persist across the north where cloud cover and rainfall were more widespread. Cloud cover is becoming more extensive again over southern Minnesota in association with a remnant MCV. Focus of this forecast remains on the severe weather and flash flooding potential through this evening. Severe Weather and Flood Outlook: Destabilization is actively taking place early this afternoon over central and east-central Wisconsin where mixed- layer CAPE is climbing upwards of 1000 J/kg. With further solar heating, thunderstorms are expected to redevelop in a buoyant airmass south of the front and across central Wisconsin in the 18-20Z time frame. These storms should track east through the afternoon before propagating southeast this evening as a cold pool becomes established. Deep layer shear of 25 to 35 knots is expected in the area of greatest concern across central and east- central Wisconsin. This shear profile will be supportive of a few bowing structures and perhaps an isolated supercell. Given the modest shear aloft, conditions will be most favorable for damaging wind gusts rather than severe hail. High freezing levels around 15,000 feet and poor mid-level lapse rates do not favor large hail, except within the strongest rotating updrafts. A weak, isolated tornado will also be possible, most likely focused along an outflow boundary or lake breeze where low- level vorticity is enhanced. The greatest period of concern is from 3 to 7 PM before storms shift south and east of the forecast area. Scattered shower and storm activity could persist into the overnight period, but a stabilizing atmosphere should keep intensities below severe levels. Upper-level flow will be nearly parallel to the surface front within a corridor of precipitable water values approaching 2.00 inches and high freezing levels. High rainfall rates of 2 to 3 inches per hour are expected in the strongest storms, which could lead to localized flash flooding in vulnerable urban, low-lying, and poorly drained areas. Fog Potential Late Tonight: After the rain winds down late tonight into Thursday morning, there is a decent signal for fog development, particularly across central to north-central Wisconsin where clearing will occur first. Considerable uncertainty exists regarding how long showers stick around into Thursday. A moist boundary layer, weak cyclonic flow in the low levels, and weak shortwave impulses aloft could keep light showers lingering into the afternoon over central and east- central Wisconsin. Excessive Heat Outlook: An amplified upper air pattern featuring a dominant upper- level ridge is expected to build northeast into the region Friday through the weekend and persist into early next week. High pressure at the surface will slide across the area Friday through the weekend. While minor signals for spotty shower activity exist in some medium-range guidance, forcing is non- existent beneath the building ridge, and a dry forecast has been maintained. The primary story in the extended period will be potential for excessive heat. Very warm air aloft will accompany the building ridge will argue for surface high temperatures climbing into the upper 80s to lower 90s by Monday and Tuesday. Coupled with humidities remaining high, minor heat- related impacts appear possible at this time for those outdoors. Some relief from the heat and humidity is expected towards the middle to end of the next work week as the ridge begins to suppress southward. && .AVIATION...for 18Z TAF Issuance Issued at 1153 AM CDT Wed Jul 8 2026 Late this morning, a cold front stretches from west-central Wisconsin to north-central Wisconsin. MVFR to IFR ceilings exist along and north of the front while VFR conditions prevail to the south and south of RHI. This front will provide the focus for clusters of showers and storms this afternoon and evening. Thunderstorm redevelopment is expected 19-20Z with impacts into RHI/AUW/CWA starting during this timeframe. These storms are expected to increase in coverage and proceed into the Fox Valley in the 22-23Z period. Strong storms are likely with gusts in excess of 40 mph possible with ceilings and visibilities falling to MVFR and IFR/LIFR respectively. After the initial push of storms, scattered showers with embedded thunder looking to continue through much of the evening, while light showers could persist across parts of central and east- central WI into Thu morning. Late tonight, there is a decent signal for ground fog to develop. Central and north-central WI have potential for sub-IFR visibilities. The fog should lift into a MVFR stratus deck after about 15Z. Winds will be light over the period. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && DISCUSSION.....MPC AVIATION.......MPC
Hazardous weather outlook, Jul 8, 1:15 PM CDT, 3 hours 5 minutes before
Hazardous Weather Outlook National Weather Service Green Bay WI 115 PM CDT Wed Jul 8 2026 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-091815- 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- 115 PM CDT Wed Jul 8 2026 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Tonight Strong to severe thunderstorms are possible between 3 and 8 PM, mainly across central and east-central Wisconsin. Damaging winds is the primary risk, although small hail and an isolated tornado are also possible. Favorable conditions for localized flash flooding will exist this afternoon and evening. Rainfall rates as high as 2-3" per hour could create urban flooding, ponding of water on roadways, and rising water levels in ditches, creeks and rivers. Patchy dense fog will restrict visibilities over north-central Wisconsin late tonight. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday There is a chance of thunderstorms on Thursday. Severe weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotters will likely be needed this afternoon into the evening, especially across central and east-central WI. Spotters are requested to report wind gusts over 40 mph, wind damage and any localized flooding. LMZ521-522-541>543-091815- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 115 PM CDT Wed Jul 8 2026 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight Thunderstorms are possible late this afternoon and tonight. Some of the storms will be capable of producing strong winds and hail, along with localized visibilities below one mile in heavy rain. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday There is a small chance of a thunderstorm on Thursday south of Manitowoc. MPC
In the hours before
Special weather statement, Jul 8, 2:10 PM CDT, 2 hours 10 minutes before
Special Weather Statement
National Weather Service Green Bay WI
210 PM CDT Wed Jul 8 2026
WIZ030-036-081945-
Portage WI-Marathon WI-
210 PM CDT Wed Jul 8 2026
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN PORTAGE AND
SOUTHEASTERN MARATHON COUNTIES UNTIL 245 PM CDT...
At 210 PM CDT, Doppler radar was tracking a strong thunderstorm near
Stevens Point, moving east at 25 mph.
HAZARD...Wind gusts up to 40 mph and nickel 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...
Stevens Point and Whiting around 210 PM CDT.
Other locations impacted by this strong thunderstorm include Jordan,
Park Ridge, Dewey Marsh Wildlife Area, Stockton, Ellis, Polonia,
North Star, Custer, Shantytown and Nelsonville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Monitor the weather situation closely and be alert for threatening
weather conditions.
&&
LAT...LON 4450 8963 4465 8964 4471 8944 4474 8923
4457 8922 4449 8922
TIME...MOT...LOC 1909Z 265DEG 21KT 4458 8949
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH
GKLocal storm report, Jul 8, 4:10 PM CDT, 10 minutes before
Preliminary Local Storm Report
National Weather Service Green Bay WI
410 PM CDT Wed Jul 8 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0403 PM Hail 4 NE Fremont 44.32N 88.82W
07/08/2026 E0.25 Inch Waupaca WI Public
&&The office that day
Everything else NWS Green Bay, WI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 8, 3:47 AM CDT | Special Weather Statement | GRB | Oneida, Vilas | 58 min |
| Jul 8, 4:25 AM CDT | Special Weather Statement | GRB | Langlade, Lincoln | 65 min |
| Jul 8, 2:10 PM CDT | Special Weather Statement | GRB | Portage | 35 min |
| Jul 8, 2:37 PM CDT | Severe Thunderstorm Warning | GRB | Portage, Waupaca | 38 min |
| Jul 8, 2:52 PM CDT | Areal Flood Advisory | GRB | Outagamie, Portage, Waupaca | 3 hr |
| Jul 8, 2:56 PM CDT | Severe Thunderstorm Warning | GRB | Shawano, Waupaca | 49 min |
| Jul 8, 3:11 PM CDT | Severe Thunderstorm Warning | GRB | Outagamie, Waupaca, Waushara, Winnebago | 49 min |
| Jul 8, 3:18 PM CDT | Severe Thunderstorm Warning | GRB | Outagamie, Shawano | 42 min |
| Jul 8, 3:30 PM CDT | Areal Flood Advisory | GRB | Outagamie, Shawano, Waupaca | 2 hr |
| Jul 8, 4:03 PM CDT | Areal Flood Advisory | GRB | Brown | 4 hr |
| Jul 8, 4:20 PM CDT | Severe Thunderstorm Warning | GRB | Brown, Kewaunee, Manitowoc | 40 min |
| Jul 8, 4:36 PM CDT | Special Marine Warning | GRB | 97 min | |
| Jul 8, 4:39 PM CDT | Severe Thunderstorm Warning | GRB | Kewaunee, Manitowoc | 34 min |
| Jul 8, 4:56 PM CDT | Special Weather Statement | GRB | Calumet | 34 min |
| Jul 8, 5:09 PM CDT | Areal Flood Advisory | GRB | Florence, Forest, Langlade, Lincoln, Oneida | 82 min |
| Jul 8, 5:11 PM CDT | Special Marine Warning | GRB | 64 min | |
| Jul 8, 5:20 PM CDT | Areal Flood Advisory | GRB | Brown, Calumet, Manitowoc, Winnebago | 106 min |
| Jul 8, 5:43 PM CDT | Areal Flood Advisory | GRB | Marathon, Outagamie, Portage, Shawano, Waupaca, Wood | 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.