Flash Flood Warning 4, NWS Green Bay, WI

861 
WGUS73 KGRB 140552
FFSGRB

Flash Flood Statement
National Weather Service Green Bay WI
1252 AM CDT Tue Apr 14 2026

WIC009-015-061-071-087-139-140900-
/O.CON.KGRB.FF.W.0004.000000T0000Z-260414T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Brown WI-Calumet WI-Kewaunee WI-Manitowoc WI-Outagamie WI-
Winnebago WI-
1252 AM CDT Tue Apr 14 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 4 AM CDT EARLY THIS
MORNING FOR NORTHERN CALUMET, MANITOWOC, NORTHERN WINNEBAGO, SOUTHERN
BROWN, KEWAUNEE AND SOUTHERN OUTAGAMIE COUNTIES...

At 1252 AM CDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 2 and 4 inches of rain have
fallen. Additional rainfall amounts up to 1 inch are possible in the
warned area. Flash flooding is ongoing or expected to begin shortly.
Road flooding was reported in De Pere and Mishicot.

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, Appleton, Manitowoc, Kewaunee, Menasha, Kaukauna, Little
  Chute, Kimberly, Algoma, Brillion, Luxemburg, Denmark, Two Creeks,
  Bellevue, High Cliff State Park, Darboy, Northern Lake Winnebago,
  Central Lake Winnebago and Lake Poygan.

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 4424 8886 4424 8874 4428 8874 4464 8737
      4462 8735 4456 8740 4454 8742 4446 8745
      4445 8745 4438 8747 4432 8749 4429 8748
      4422 8747 4415 8750 4412 8753 4408 8759
      4407 8888 4415 8889 4420 8889

FLASH FLOOD...RADAR INDICATED

$$

Bersch

143 
WGUS73 KGRB 140857
FFSGRB

Flash Flood Statement
National Weather Service Green Bay WI
357 AM CDT Tue Apr 14 2026

WIC009-015-061-071-087-139-140907-
/O.EXP.KGRB.FF.W.0004.000000T0000Z-260414T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Brown WI-Calumet WI-Kewaunee WI-Manitowoc WI-Outagamie WI-
Winnebago WI-
357 AM CDT Tue Apr 14 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 4 AM CDT EARLY THIS MORNING FOR
NORTHERN CALUMET, MANITOWOC, NORTHERN WINNEBAGO, SOUTHERN BROWN,
KEWAUNEE AND SOUTHERN OUTAGAMIE COUNTIES...

Flash flooding is no longer expected to pose a threat. However, a
flood advisory is in effect until 10 AM this morning as some roads
remain flooded, along with some rising rivers, creeks and streams.
Please continue to heed remaining road closures.

A Flood Watch remains in effect until 700 AM CDT Wednesday for
portions of central, east central, and northeast Wisconsin.

&&

LAT...LON 4424 8886 4424 8874 4428 8874 4464 8737
      4462 8735 4456 8740 4454 8742 4446 8745
      4445 8745 4438 8747 4432 8749 4429 8748
      4422 8747 4415 8750 4412 8753 4408 8759
      4407 8888 4415 8889 4420 8889

$$

Bersch

Area Forecast Discussion
National Weather Service Green Bay WI
746 PM CDT Mon Apr 13 2026

Updated aviation portion for 00Z TAF issuance

.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...for 00Z TAF Issuance
Issued at 746 PM CDT Mon Apr 13 2026

Widespread showers and storms will continue to impact AUW/CWA/ATW
/GRB/MTW this evening. The strongest storms could contain heavy
rain, hail and gusty winds. Some fog will along linger near Lake
Michigan. The activity will end west to east from 03-07z. Low
clouds and fog will linger overnight, with clouds lifting and
scattering out later Tuesday morning and afternoon. Another round
of storms is possible at ATW/GRB/MTW Tuesday afternoon.

&&

.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...
Flood Watch until 7 AM CDT Tuesday for WIZ013-018>022-030-031-
035>040-045-048>050-073-074.
&&

DISCUSSION.....JM
AVIATION.......Bersch
HYDROLOGY......Kieckbusch/JM

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.

Preliminary Local Storm Report
National Weather Service Green Bay WI
928 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0923 PM     Hail             Plover                  44.46N 89.54W
04/13/2026  M1.00 Inch       Portage            WI   Trained Spotter

            Hailing at the time of the report.

&&

Preliminary Local Storm Report
National Weather Service Green Bay WI
934 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0818 PM     Hail             2 SE Anston             44.59N 88.14W
04/13/2026  E0.75 Inch       Brown              WI   Public

            Report from mPING: Dime (0.75 in.).

&&

Preliminary Local Storm Report
National Weather Service Green Bay WI
936 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0935 PM     Rain             1 ENE Clintonville      44.62N 88.73W
04/13/2026  M2.60 Inch       Waupaca            WI   AWOS

            Rainfall total through 9:15 pm. Rain will
            continue for several more hours.

&&

Preliminary Local Storm Report
National Weather Service Green Bay WI
945 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0925 PM     Flash Flood      1 WNW Marshfield        44.66N 90.18W
04/13/2026                   Wood               WI   Law Enforcement

            Several roads were flooded. Barricades were
            set up to close off the roads.

&&

Special Weather Statement
National Weather Service Green Bay WI
956 PM CDT Mon Apr 13 2026

WIZ037-045-140330-
Waushara WI-Waupaca WI-
956 PM CDT Mon Apr 13 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT WAUPACA AND
NORTHEASTERN WAUSHARA COUNTIES UNTIL 1030 PM CDT...

At 956 PM CDT, Doppler radar was tracking a line of strong
thunderstorms extending from 11 miles northeast of Amherst to near
Hartman Creek State Park, or extending from 17 miles north of Waupaca
to 9 miles southwest of Waupaca, moving east at 35 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

The strong thunderstorm will be near...
  Chain O' Lakes-King, Waupaca and Hartman Creek State Park around
  1000 PM CDT. Fremont around 1020 PM CDT.

Other locations impacted by this strong thunderstorm include Rural,
Scandinavia, King, Iola, Northland, Sheridan, Ogdensburg, Lind
Center, Manawa and Weyauwega.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 4423 8924 4424 8924 4424 8922 4459 8922
      4459 8874 4425 8874
TIME...MOT...LOC 0256Z 271DEG 29KT 4459 8918 4443 8918 4425 8919

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

MPC

Special Weather Statement
National Weather Service Green Bay WI
1035 PM CDT Mon Apr 13 2026

WIZ038>040-045-048>050-140430-
Calumet WI-Kewaunee WI-Outagamie WI-Winnebago WI-Waushara WI-
Manitowoc WI-Brown WI-
1035 PM CDT Mon Apr 13 2026

...STRONG THUNDERSTORMS WILL IMPACT BROWN...SOUTHWESTERN KEWAUNEE...
CALUMET...WINNEBAGO...SOUTHEASTERN WAUSHARA...OUTAGAMIE AND NORTHERN
MANITOWOC COUNTIES THROUGH 1130 PM CDT...

At 1034 PM CDT, Doppler radar was tracking a cluster of strong
thunderstorms along a line extending from 7 miles northeast of New
London to 11 miles east of Fremont to near Berlin to 8 miles north of
Montello. Movement was east at 40 mph.

HAZARD...Half inch hail and torrential rainfall.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vegetation is possible.

Strong thunderstorms will be near...
  Black Creek around 1040 PM CDT.
  Appleton, Menasha, and Northern Lake Winnebago around 1045 PM CDT.
  Oshkosh, Little Chute, and Kimberly around 1050 PM CDT.
  Kaukauna, Darboy, Rush Lake, and Central Lake Winnebago around
  1055 PM CDT.
  High Cliff State Park around 1105 PM CDT.
  Green Bay around 1110 PM CDT.
  Brillion and Bellevue around 1115 PM CDT.

Other locations impacted by these storms include Pickett, Butte Des
Morts, Curran, Wayside, Freedom, Borth, Zittau, Harbor Springs,
Allenville, and St John.

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.

A Severe Thunderstorm Watch remains in effect until 400 AM CDT for
central, northeastern and east central Wisconsin.

&&

LAT...LON 4390 8889 4398 8889 4398 8920 4404 8904
      4424 8877 4424 8874 4428 8872 4454 8869
      4455 8758 4422 8762 4399 8794 4391 8816
      4394 8816 4394 8840 4389 8840
TIME...MOT...LOC 0334Z 273DEG 35KT 4446 8863 4428 8865 4405 8897 4391
8933

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...<30 MPH

Kieckbusch