Flash Flood Warning 1, NWS Green Bay, WI

296 
WGUS73 KGRB 140040
FFSGRB

Flash Flood Statement
National Weather Service Green Bay WI
740 PM CDT Mon Apr 13 2026

WIC073-097-141-140315-
/O.CON.KGRB.FF.W.0001.000000T0000Z-260414T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Marathon WI-Portage WI-Wood WI-
740 PM CDT Mon Apr 13 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT THIS
EVENING FOR SOUTHWESTERN MARATHON, NORTHWESTERN PORTAGE AND NORTHERN
WOOD COUNTIES...

At 740 PM CDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 1.5 and 2.5 inches of rain have
fallen. Additional rainfall amounts of 0.5 to 1 inch 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...
  Marshfield, Spencer, Pittsville, Stratford, Marathon City, Edgar,
  Rib Falls, Hewitt, Sherry, Auburndale, Vesper, Junction City,
  Rudolph, Arpin, Milladore, Fenwood and Rozellville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

LAT...LON 4469 9030 4497 9030 4497 8974 4445 8973
      4444 9030

FLASH FLOOD...RADAR INDICATED

$$

JLA

891 
WGUS73 KGRB 140318
FFSGRB

Flash Flood Statement
National Weather Service Green Bay WI
1018 PM CDT Mon Apr 13 2026

WIC073-097-141-140328-
/O.EXP.KGRB.FF.W.0001.000000T0000Z-260414T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Marathon WI-Portage WI-Wood WI-
1018 PM CDT Mon Apr 13 2026

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHWESTERN MARATHON,
NORTHWESTERN PORTAGE AND NORTHERN WOOD COUNTIES...

The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed remaining
road closures.

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

&&

LAT...LON 4469 9030 4497 9030 4497 8974 4445 8973
      4444 9030

$$

Bersch

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/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.

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

Kurimski

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

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

0434 PM     Hail             Ellis                   44.58N 89.43W
04/13/2026  M1.00 Inch       Portage            WI   Public

&&

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

WIZ019>021-132230-
Northern Oconto County WI-Menominee WI-Langlade WI-
507 PM CDT Mon Apr 13 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHERN MENOMINEE...
SOUTHEASTERN LANGLADE AND NORTHERN OCONTO COUNTIES UNTIL 530 PM
CDT...

At 507 PM CDT, Doppler radar was tracking a strong thunderstorm 6
miles southwest of Gardner Dam Scout Camp, or 21 miles north of
Shawano, moving northeast at 35 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...
  Neopit and Big Smokey Falls around 510 PM CDT. Gardner Dam Scout
  Camp and White Lake around 515 PM CDT. Mountain around 525 PM CDT.

Other locations impacted by this strong thunderstorm include
Intersection Of Hwy 55 And County M, Langlade, Boulder Lake
Campground, Fredenberg Lake and Bagley Rapids Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is also occurring with this storm and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4512 8884 4531 8853 4513 8835 4494 8870
      4505 8895
TIME...MOT...LOC 2207Z 232DEG 30KT 4506 8874

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Kurimski

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

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

0452 PM     Hail             Spencer                 44.76N 90.28W
04/13/2026  M0.75 Inch       Marathon           WI   Amateur Radio

&&