Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 8, NWS Green Bay, WI
NWS Green Bay, WI issued this severe thunderstorm warning at Apr 13, 2026, 4:22 PM CDT for Marathon County, Portage County, Wisconsin. It was in force for 53 min. 2 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
- Apr 13, 2026, 4:22 PM CDT (21:22 UTC)
- Expired
- Apr 13, 2026, 5:15 PM CDT
- In force
- 53 min
- Issued by
- NWS Green Bay, WI
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 50.0 mph
Counties Marathon County, WI, Portage County, WI
The radar
The Green Bay radar (KGRB), 108 km from the middle of the area, began a volume at 21:26 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 |
|---|---|---|---|
| Apr 13, 4:34 PM CDT | HAIL 1 | Ellis, WI | && |
| Apr 13, 4:34 PM CDT | HAIL 1 | Ellis, 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 2 storm reports to this severe thunderstorm warning; the first came 12 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Apr 13, 3:11 PM CDT | Tornado Watch | SPC | 7 hr |
The nearest sounding before it
Minneapolis, MN (KMPX), launched 12:00Z, 9.4 hours before the alert went out and 328 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
- 8 J/kg
- Mixed-layer CIN
- -259 J/kg
- Mixed-layer LCL
- 1506 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 124 m²/s²
- 0-3 km storm-relative helicity
- 229 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
992
WUUS53 KGRB 132122
SVRGRB
WIC073-097-132215-
/O.NEW.KGRB.SV.W.0008.260413T2122Z-260413T2215Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Green Bay WI
422 PM CDT Mon Apr 13 2026
The National Weather Service in Green Bay has issued a
* Severe Thunderstorm Warning for...
Southeastern Marathon County in central Wisconsin...
Northeastern Portage County in central Wisconsin...
* Until 515 PM CDT.
* At 422 PM CDT, a severe thunderstorm was located 7 miles northeast
of Stevens Point, moving northeast at 20 mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
* This severe thunderstorm will be near...
Stevens Point around 425 PM CDT.
Other locations impacted by the severe thunderstorm include Ellis,
Jordan, Polonia, Dewey Marsh Wildlife Area, Stockton, Park Ridge,
North Star, Rosholt, Shantytown and Holt.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing large hail.
Torrential rainfall is also occurring with this storm and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
A Tornado Watch remains in effect until 1000 PM CDT Monday for a
portion of central Wisconsin.
&&
LAT...LON 4469 8961 4487 8958 4485 8923 4468 8923
4448 8929 4454 8963
TIME...MOT...LOC 2121Z 203DEG 15KT 4460 8947
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
Kurimski3 follow-up statements
722
WWUS53 KGRB 132134
SVSGRB
Severe Weather Statement
National Weather Service Green Bay WI
434 PM CDT Mon Apr 13 2026
WIC073-097-132215-
/O.CON.KGRB.SV.W.0008.000000T0000Z-260413T2215Z/
Marathon WI-Portage WI-
434 PM CDT Mon Apr 13 2026
...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT FOR
SOUTHEASTERN MARATHON AND NORTHEASTERN PORTAGE COUNTIES...
At 434 PM CDT, a severe thunderstorm was located 7 miles southwest of
Bevent, or 11 miles northeast of Stevens Point, moving northeast at
30 mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
This severe thunderstorm will be near...
Bevent around 450 PM CDT. Weston around 455 PM CDT.
Other locations impacted by the severe thunderstorm include
Shantytown, North Star, Dewey Marsh Wildlife Area, Ellis, Rosholt,
Holt, Galloway, Pike Lake and Elderon.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing large hail.
Torrential rainfall is also occurring with this storm and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
A Tornado Watch remains in effect until 1000 PM CDT Monday for a
portion of central Wisconsin.
&&
LAT...LON 4469 8961 4487 8958 4485 8923 4468 8923
4453 8927 4459 8962
TIME...MOT...LOC 2122Z 207DEG 26KT 4460 8951
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
Kurimski083
WWUS53 KGRB 132152
SVSGRB
Severe Weather Statement
National Weather Service Green Bay WI
452 PM CDT Mon Apr 13 2026
WIC073-097-132215-
/O.CON.KGRB.SV.W.0008.000000T0000Z-260413T2215Z/
Marathon WI-Portage WI-
452 PM CDT Mon Apr 13 2026
...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT FOR
SOUTHEASTERN MARATHON AND NORTHEASTERN PORTAGE COUNTIES...
At 452 PM CDT, a severe thunderstorm was located over Bevent, or 20
miles northeast of Stevens Point, moving northeast at 30 mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
This severe thunderstorm will be near...
Bevent around 455 PM CDT.
Other locations impacted by the severe thunderstorm include Pike
Lake, Holt, Galloway and Elderon.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing large hail.
Torrential rainfall is also occurring with this storm and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
A Tornado Watch remains in effect until 1000 PM CDT Monday for a
portion of central Wisconsin.
&&
LAT...LON 4469 8950 4486 8941 4485 8923 4468 8923
4458 8926 4463 8947
TIME...MOT...LOC 2134Z 222DEG 24KT 4466 8944
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
Kurimski234
WWUS53 KGRB 132205
SVSGRB
Severe Weather Statement
National Weather Service Green Bay WI
505 PM CDT Mon Apr 13 2026
WIC073-097-132215-
/O.EXP.KGRB.SV.W.0008.000000T0000Z-260413T2215Z/
Marathon WI-Portage WI-
505 PM CDT Mon Apr 13 2026
...SEVERE THUNDERSTORM WARNING WILL EXPIRE AT 515 PM CDT FOR
SOUTHEASTERN MARATHON AND NORTHEASTERN PORTAGE COUNTIES...
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.
A Tornado Watch remains in effect until 1000 PM CDT Monday for a
portion of central Wisconsin.
&&
LAT...LON 4469 8950 4486 8941 4485 8923 4468 8923
4458 8926 4463 8947
TIME...MOT...LOC 2152Z 222DEG 24KT 4476 8932
$$
KurimskiWhat forecasters said that day
The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Apr 13, 2:44 PM CDT, 1 hour 38 minutes earlier. Its key messages:
- Thunderstorms will develop late this afternoon and continue into the overnight hours with hail in excess of 2 inches, damaging winds and a tornado possible with the strongest storms. The highest risk is across central Wisconsin.
- Rainfall amounts of 1 to 3 inches across parts of central into east-central Wisconsin may lead to additional flood concerns through tonight.
- An active stretch of weather continues through late week with continued periods of showers and storms. The risk area for severe storms shifts south on Tuesday, but extends north into parts of central and east-central Wisconsin.
- Minor to moderate river flooding is ongoing or forecast to occur on several area rivers. Expect many rivers to rise this week due to additional rain and runoff from Upper Michigan, with the greatest impacts expected on the Menominee River, where some locations may see major flooding during the mid to late part of the week.
Area forecast discussion, Apr 13, 2:44 PM CDT, 1 hour 38 minutes before
Area Forecast Discussion
National Weather Service Green Bay WI
244 PM CDT Mon Apr 13 2026
.KEY MESSAGES...
- Thunderstorms will develop late this afternoon and continue
into the overnight hours with hail in excess of 2 inches,
damaging winds and a tornado possible with the strongest
storms. The highest risk is across central Wisconsin.
- Rainfall amounts of 1 to 3 inches across parts of central into
east-central Wisconsin may lead to additional flood concerns
through tonight.
- An active stretch of weather continues through late week with
continued periods of showers and storms. The risk area for
severe storms shifts south on Tuesday, but extends north into
parts of central and east-central Wisconsin.
- Minor to moderate river flooding is ongoing or forecast to
occur on several area rivers. Expect many rivers to rise this
week due to additional rain and runoff from Upper Michigan,
with the greatest impacts expected on the Menominee River,
where some locations may see major flooding during the mid to
late part of the week.
&&
.DISCUSSION...
Issued at 245 PM CDT Mon Apr 13 2026
Tonight: Severe Storms/Heavy Rain
Early afternoon surface analysis indicated a surface low over
central Nebraska with a warm front snaking eastward across
northern Iowa into central Wisconsin. MLCAPE has increased to
around 1000 J/kg across central Wisconsin with some inhibition
noted.
Late this afternoon, expect more focused storm
initiation/intensification generally in the vicinity of the
warm front and nose of the low- level jet. Surface-based
instability is maximized over central Wisconsin (1000-2000 J/kg)
by late this afternoon with effective shear around 40-50 kts.
Combined with steep lapse rates already sampled by the 18Z GRB
RAOB, the environment will be supportive of large to very large
hail. The tornado risk likely will be highest along the warm
front from west-central Wisconsin into perhaps central
Wisconsin as the low-level jet increases early this evening and
overlaps the warm front/instability axis. Damaging wind risk
will depend on the degree of upscale growth/organization of
storms. Overall, the severe weather risk lessens with northward
extent.
Precipitable water values remain near the top of climatology for
mid April. HREF probability matched mean 24-hr rainfall is in
the 1 to 3 inch range across parts of central into east-central
Wisconsin through tonight, on the nose of the low-level jet.
However, rainfall amounts will depend on the organization and
degree of training. This rainfall could exacerbate already
saturated soils.
Areas of fog may also develop overnight behind the storms.
Tuesday: Additional storms
The front slides south on Tuesday with the instability axis also
displaced south. The placement of the boundary will impact the
northward extent of severe weather during the
afternoon/evening. RAP hodographs show lesser low-level shear
although an elongated profile favorable for large hail and
winds. Currently the highest risk of severe storms is across
southern Wisconsin, but could extend into parts of east-central
Wisconsin.
Wednesday-Monday: Active into the weekend
Southwest flow aloft persists into late week keeping the area in
a warm, wet pattern. Another shortwave trough will bring
additional shower (40-80%) chances Wednesday into Thursday. A
more dynamic trough is slated to impact the region late Friday
into the weekend bringing additional widespread rainfall and
storms. The northward extent of greater instability is somewhat
uncertain with this system, impacting severe weather potential,
but this will be something to watch in the coming days. Drier
and cooler weather is expected behind this system for early next
week.
&&
.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1251 PM CDT Mon Apr 13 2026
Widespread showers and storms will develop late this afternoon
into the overnight hours with MFVR/IFR conditions. Initial
storms may begin to initiate by 21-22Z today, becoming more
widespread this evening. Areas of fog/low clouds will likely
persist into Tuesday.
&&
.HYDROLOGY...
Issued at 245 PM CDT Mon Apr 13 2026
Flooding is expected to continue on several area rivers during
the week, and will be exacerbated by periodic heavy rainfall.
Runoff from Upper Michigan is still expected to bring moderate
to major flooding along the Menominee River, especially during
the mid to late part of the week. If you live near a river or
stream, keep a close eye on water levels this week and monitor
the latest Flood Warnings from the National Weather Service in
Green Bay.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WI...Flood Watch through Tuesday morning for WIZ013-018>022-030-031-
035>040-045-048>050-073-074.
MARINE...None.
&&
DISCUSSION...JM
AVIATION...JM
HYDROLOGY...Kieckbusch/JMHazardous weather outlook, Apr 13, 2:51 PM CDT, 1 hour 31 minutes before
Hazardous Weather Outlook National Weather Service Green Bay WI 251 PM CDT Mon Apr 13 2026 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-142000- 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- 251 PM CDT Mon Apr 13 2026 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Tonight Elevated water levels or flooding continue along some rivers. Severe storms, including heavy rainfall, large to very large hail, damaging winds and tornado or two are possible late this afternoon into tonight. The highest risk of severe storms is across central into east- central Wisconsin. Additional flooding may occur for areas that receive heavy rainfall tonight. .DAYS TWO THROUGH SEVEN...Tuesday through Monday There is a chance of severe thunderstorms south of a line from Wisconsin Rapids to Sturgeon bay during the late afternoon and evening on Tuesday. Large hail and strong winds will be the primary threats. Additional thunderstorms are possible Wednesday afternoon into Wednesday night, and again Friday night into Saturday. Elevated water levels and at least minor flooding will continue along many rivers through the week. Runoff from the Upper Peninsula will likely result in moderate to possibly major flooding on the Menominee River during the mid to late part of the week. .SPOTTER INFORMATION STATEMENT... Spotters should report severe weather and flooding to the National Weather Service in Green Bay. LMZ521-522-541>543-142000- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 251 PM CDT Mon Apr 13 2026 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight Thunderstorms, some possibly strong to severe, are expected tonight. Areas of fog are possible. .DAYS TWO THROUGH SEVEN...Tuesday through Monday Thunderstorms will be possible at times Tuesday through Wednesday night, and again Friday night into Saturday. Severe storms will be possible Tuesday evening.
In the hours before
Special weather statement, Apr 13, 4:16 PM CDT, 6 minutes before
Special Weather Statement
National Weather Service Green Bay WI
416 PM CDT Mon Apr 13 2026
WIZ030-036-132145-
Marathon WI-Portage WI-
416 PM CDT Mon Apr 13 2026
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN PORTAGE AND
SOUTHEASTERN MARATHON COUNTIES UNTIL 445 PM CDT...
At 416 PM CDT, Doppler radar was tracking a strong thunderstorm 5
miles northeast of Stevens Point, moving northeast at 20 mph.
HAZARD...Wind gusts up to 40 mph and penny 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 420 PM CDT.
Other locations impacted by this strong thunderstorm include Jordan,
Ellis, Polonia, Stockton, Park Ridge, Custer, Dewey Marsh Wildlife
Area, North Star, Shantytown and Holt.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Monitor the weather situation closely and be alert for threatening
weather conditions.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4469 8963 4477 8962 4475 8922 4472 8922
4449 8932 4449 8965
TIME...MOT...LOC 2116Z 203DEG 15KT 4458 8948
MAX HAIL SIZE...0.75 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 |
|---|---|---|---|---|
| Apr 12, 11:33 PM CDT | River Flood Warning | GRB | Shawano, Waupaca | 5 days |
| Apr 13, 2:04 AM CDT | Flood Watch | GRB | Brown, Calumet, Door, Kewaunee, Langlade, Lincoln and 12 more | 49 hr |
| Apr 13, 7:30 AM CDT | River Flood Warning | GRB | Portage | 4 days |
| Apr 13, 7:31 AM CDT | River Flood Warning | GRB | Portage | 3 days |
| Apr 13, 10:53 AM CDT | River Flood Warning | GRB | Lincoln, Marathon | 11 hr |
| Apr 13, 3:49 PM CDT | Small Craft Advisory | GRB | 7 hr | |
| Apr 13, 4:10 PM CDT | River Flood Warning | GRB | Florence, Forest | 8 days |
| Apr 13, 4:16 PM CDT | Special Weather Statement | GRB | Portage | 29 min |
| Apr 13, 4:43 PM CDT | Severe Thunderstorm Warning | GRB | Shawano, Waupaca | 62 min |
| Apr 13, 4:44 PM CDT | River Flood Warning | GRB | Marinette | 4 days |
| Apr 13, 4:46 PM CDT | Severe Thunderstorm Warning | GRB | Marathon | 59 min |
| Apr 13, 5:03 PM CDT | Severe Thunderstorm Warning | GRB | Portage, Wood | 57 min |
| Apr 13, 5:07 PM CDT | Special Weather Statement | GRB | Menominee | 23 min |
| Apr 13, 5:22 PM CDT | Flash Flood Warning | GRB | Marathon, Portage, Wood | 5 hr |
| Apr 13, 5:23 PM CDT | Special Weather Statement | GRB | Menominee | 37 min |
| Apr 13, 5:41 PM CDT | Severe Thunderstorm Warning | GRB | Marathon, Wood | 48 min |
| Apr 13, 5:42 PM CDT | Severe Thunderstorm Warning | GRB | Langlade, Marathon, Shawano | 48 min |
| Apr 13, 5:45 PM CDT | Marine Dense Fog Advisory | GRB | 67 hr | |
| Apr 13, 5:47 PM CDT | Areal Flood Advisory | GRB | Langlade, Menominee, Oconto, Shawano, Waupaca | 3 hr |
| Apr 13, 5:55 PM CDT | Areal Flood Advisory | GRB | Marathon, Portage | 3 hr |
| Apr 13, 5:59 PM CDT | Special Weather Statement | GRB | Marinette | 46 min |
| Apr 13, 6:19 PM CDT | Severe Thunderstorm Warning | GRB | Portage, Waupaca | 41 min |
| Apr 13, 6:37 PM CDT | Special Weather Statement | GRB | Brown, Outagamie | 38 min |
| Apr 13, 6:39 PM CDT | Special Weather Statement | GRB | Lincoln | 36 min |
| Apr 13, 6:44 PM CDT | Severe Thunderstorm Warning | GRB | Lincoln, Marathon | 35 min |
| Apr 13, 6:49 PM CDT | Severe Thunderstorm Warning | GRB | Outagamie, Shawano, Waupaca | 41 min |
| Apr 13, 6:55 PM CDT | Severe Thunderstorm Warning | GRB | Marathon | 29 min |
Nearby
Severe Thunderstorm Warnings in Wisconsin, 2026Every severe thunderstorm 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.