Severe Thunderstorm Warning 39, NWS Green Bay, WI

804 
WWUS53 KGRB 122128
SVSGRB

Severe Weather Statement
National Weather Service Green Bay WI
428 PM CDT Tue May 12 2026

WIC067-122138-
/O.CAN.KGRB.SV.W.0039.000000T0000Z-260512T2200Z/
Langlade WI-
428 PM CDT Tue May 12 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR EAST CENTRAL LANGLADE
COUNTY...

The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

&&

LAT...LON 4520 8831 4520 8828 4510 8828 4514 8864
      4523 8863 4527 8831
TIME...MOT...LOC 2118Z 270DEG 27KT 4519 8868

$$


WIC083-122200-
/O.CON.KGRB.SV.W.0039.000000T0000Z-260512T2200Z/
Oconto WI-
428 PM CDT Tue May 12 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 5 PM CDT FOR
NORTHERN OCONTO COUNTY...

At 428 PM CDT, a severe thunderstorm was located near Mountain, or 28
miles north of Shawano, moving east at 30 mph.

HAZARD...60 mph wind gusts and half dollar size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to
         roofs, siding, and trees.

This severe thunderstorm will be near...
  Mountain around 435 PM CDT. Bear Paw Scout Camp around 445 PM CDT.

Other locations impacted by the severe thunderstorm include Boulder
Lake Campground and Crooked Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.

&&

LAT...LON 4520 8831 4520 8828 4510 8828 4514 8864
      4523 8863 4527 8831
TIME...MOT...LOC 2118Z 271DEG 27KT 4518 8867

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Kruk

090 
WWUS53 KGRB 122140
SVSGRB

Severe Weather Statement
National Weather Service Green Bay WI
440 PM CDT Tue May 12 2026

WIC083-122200-
/O.CON.KGRB.SV.W.0039.000000T0000Z-260512T2200Z/
Oconto WI-
440 PM CDT Tue May 12 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 5 PM CDT FOR
NORTHERN OCONTO COUNTY...

At 440 PM CDT, a severe thunderstorm was located over Bear Paw Scout
Camp, or 28 miles north of Shawano, moving east at 30 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to
         roofs, siding, and trees.

This severe thunderstorm will be near...
  Bear Paw Scout Camp and Mountain around 445 PM CDT.

Other locations impacted by the severe thunderstorm include Crooked
Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.

&&

LAT...LON 4520 8831 4520 8828 4510 8828 4512 8850
      4521 8849 4527 8831
TIME...MOT...LOC 2128Z 273DEG 27KT 4517 8855

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Kruk

447 
WWUS53 KGRB 122146
SVSGRB

Severe Weather Statement
National Weather Service Green Bay WI
446 PM CDT Tue May 12 2026

WIC083-122156-
/O.CAN.KGRB.SV.W.0039.000000T0000Z-260512T2200Z/
Oconto WI-
446 PM CDT Tue May 12 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR NORTHERN OCONTO
COUNTY...

The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled. However, small hail and
gusty winds are still possible with this thunderstorm.

&&

LAT...LON 4520 8831 4520 8828 4510 8828 4512 8850
      4521 8849 4527 8831
TIME...MOT...LOC 2140Z 273DEG 27KT 4517 8842

$$

Kruk

Area Forecast Discussion
National Weather Service Green Bay WI
140 PM CDT Tue May 12 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Scattered thunderstorms are expected to redevelop this afternoon
  and early evening. A few strong storms are possible in eastern
  Wisconsin, capable of producing small hail and wind gusts in
  excess of 40 mph.

- Windy conditions expected through Wednesday, with hazardous
  conditions for small craft on the lake and bay.

- Additional rain chances expected Late Thursday night into
  Friday, and late Saturday night through at least Monday.

- Low relative humidity (RHs 20-35%) on Wednesday and Thursday
  will result in elevated fire weather conditions.

&&

.DISCUSSION...
Issued at 140 PM CDT Tue May 12 2026

The latest RAP analysis and satellite imagery show a surface low
pressure system positioned north of Hayward, Wisconsin, early this
afternoon. An associated warm front is currently lifting across
western Wisconsin, while a trailing cold front extends into
central Minnesota. An initial round of showers and storms tied to
warm advection is currently exiting the lakeshore of northeast
Wisconsin. In its wake, clearing skies over central and western
portions of the state are allowing for significant solar
insolation. A potent shortwave is moving east across western Lake
Superior, which will serve as the primary dynamic driver for
redevelopment later today.

As the surface low and dynamic shortwave track across northern
Wisconsin this afternoon, scattered showers and thunderstorms are
forecast to redevelop after 3 pm. The highest coverage is expected
to remain north of the Highway 29 corridor where forcing is most
robust. The primary forecast uncertainty involves the degree of
destabilization; while some guidance suggests moisture pooling
could push dewpoints into the lower 50s, upstream observations in
the 40s suggest a more modest instability profile. Given the
mixing potential, storms should remain widely scattered to
scattered in nature with small hail and gusty winds as the main
threats. An isolated near- severe storm is possible over eastern Wisconsin
before activity wanes by 7 pm.

Strong cold advection will settle into the region tonight behind
the departing low. While most areas will see a decrease in
precipitation, scattered showers will likely persist across far
northern Wisconsin until late tonight. Tightening pressure
gradients will maintain breezy conditions and lead to an increase
in cloud cover overnight. These clouds will linger through
Wednesday morning before drier air and subsidence allow for
partial clearing in the afternoon. Cooler high temperatures in the
50s to middle 60s are expected for Wednesday.

The arrival of a cooler and drier airmass will lead to elevated
fire weather conditions on Wednesday and Thursday. For Wednesday,
northwest winds gusting between 30 and 35 mph will combine with
relative humidity values dropping to near 35 percent. While the
humidity is somewhat marginal, the strength of the winds will
necessitate monitoring. By Thursday, high pressure moving across
the Great Lakes will cause winds to lighten, which should
alleviate the fire weather potential despite even lower humidity
values in the 20 to 30 percent range. Patchy frost also looks
possible Wednesday night as radiational cooling allows lows to dip
into the middle to upper 30s.

Marine conditions will remain hazardous for small craft through
Wednesday evening. South winds gusting to 30 knots this afternoon
will veer northwest tonight and remain gusty through much of
Wednesday. This will maintain wave heights of 3 to 5 feet on Green
Bay and 6 to 10 feet on the Lake Michigan nearshore waters into
the evening before waves settle into the 2 to 4 ft range.
Conditions should improve by Wednesday night as high pressure
builds in.

Looking further ahead, a pattern change is expected late this week
as a ridge builds over the eastern United States. This will
transition the region into a warmer and more unstable airmass
within southwest flow. Light rain is possible late Thursday night
into Friday morning within a warm advection pattern, though
capping aloft may limit thunderstorm potential. A more significant
system is projected for the late Sunday through Monday timeframe.
As deep moisture surges into the region, with precipitable water
values potentially exceeding the 90th percentile, there will be an
increased risk for heavy rainfall and organized thunderstorms.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1206 PM CDT Tue May 12 2026

Low pressure north of Hayward will track east across northern
Wisconsin this afternoon. South winds gusting 25 to 30 kts will
veer SW-W as a cold front moves through, eventually becoming NW by
early evening. Low-level wind shear will abate early this
afternoon, though marginal LLWS returns to KRHI tonight.

Scattered showers and thunderstorms are expected to redevelop
between 20z and 01z, primarily north of Hwy 29. Small hail and
gusty winds are the main threats. While a brief severe storm is
possible, confidence in severe storm occurrence is low.

Ceilings will deteriorate to MVFR from northwest to southeast
this evening behind the front. These MVFR decks (015-030 AGL) will
persist through Wednesday morning. Scattered light showers may
linger over far northern WI through the evening. Some improvement
toward VFR is expected after 15z Wednesday, though NW winds will
remain breezy with gusts to 25 kts.

&&

.FIRE WEATHER...
Issued at 140 PM CDT Tue May 12 2026

Pine fuels have reached their peak volatility and fine fuels have
still not greened up over northern WI, so upcoming dry and windy
weather on Wednesday and low relative humidity (RHs 20-30%) on
Thursday will result in elevated fire weather conditions. Will
also need to monitor the fire weather potential on Saturday.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION.....MPC
AVIATION.......MPC
FIRE WEATHER...MPC

Hazardous Weather Outlook
National Weather Service Green Bay WI
140 PM CDT Tue May 12 2026

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-131845-
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-
140 PM CDT Tue May 12 2026

This Hazardous Weather Outlook is for north-central and northeast
Wisconsin.

.DAY ONE...Tonight

Storms are expected to redevelop in eastern WI during the mid to
late afternoon, with isolated strong to near severe storms
possible in eastern WI, including the Fox Valley, between 3 pm
and 7 pm. Small hail and strong wind gusts will be the primary
hazards.

.DAYS TWO THROUGH SEVEN...Wednesday through Tuesday

Elevated fire weather conditions are expected Wednesday into
Thursday and also on Saturday.

Thunderstorms will be possible at times late Thursday night into
Friday evening, and also from late Saturday night through Monday.
Locally heavy rainfall is expected.

.SPOTTER INFORMATION STATEMENT...

Spotters should relay any reports of hail or wind gusts in excess
of 40 mph to the National Weather Service in Green Bay this
afternoon.

LMZ521-522-541>543-131845-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
140 PM CDT Tue May 12 2026

This Hazardous Weather Outlook is for portions of northwest Lake
Michigan and the waters of Green Bay.

.DAY ONE...Tonight

There is a slight chance of thunderstorms from 4 to 7 pm today.

A Small Craft Advisory is in effect for the lake and bay.

.DAYS TWO THROUGH SEVEN...Wednesday through Tuesday

Conditions hazardous to small craft are expected through early
Wednesday evening on the bay and lake. A Small Craft Advisory is
in effect.

Conditions hazardous to small craft are possible again Friday
into Friday night.

Thunderstorms will be possible on Friday, and again from Sunday
into Monday.

MPC

Special Weather Statement
National Weather Service Green Bay WI
405 PM CDT Tue May 12 2026

WIZ019>021-122130-
Menominee WI-Northern Oconto County WI-Langlade WI-
405 PM CDT Tue May 12 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN MENOMINEE...
SOUTHEASTERN LANGLADE AND NORTHERN OCONTO COUNTIES UNTIL 430 PM
CDT...

At 405 PM CDT, Doppler radar was tracking a strong thunderstorm near
White Lake, or 17 miles east of Antigo, moving east at 35 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...
  White Lake around 410 PM CDT. Gardner Dam Scout Camp around 415 PM
  CDT. Mountain around 425 PM CDT.

Other locations impacted by this strong thunderstorm include
Hollister, Elton, Lily, Langlade, Boulder Lake Campground, Boot Lake
Campground and Lakewood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4529 8889 4531 8843 4509 8842 4511 8888
TIME...MOT...LOC 2104Z 268DEG 28KT 4520 8882

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

Kruk