Hail in Wisconsin, June 29, 2026

Area Forecast Discussion
National Weather Service Green Bay WI
1257 AM CDT Mon Jun 29 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- An Extreme Heat Warning is in effect from this afternoon through
  Tuesday for central Wisconsin and the Fox Valley. A Heat
  Advisory is in effect for the rest of northern and northeastern
  Wisconsin for the same time period.

- High heat and humidity will result in continued heat-related
  impacts for the middle to late part of the week.

- Gusty onshore southerly winds will result in high waves and
  dangerous currents on Lake Michigan beaches through Tuesday
  evening.

- Periodic chances for thunderstorms expected at times this week.
  Some of these storms could become strong or severe. Main hazards
  would be damaging winds, large hail, and heavy rain.

&&

.DISCUSSION...
Issued at 1257 AM CDT Mon Jun 29 2026

Severe Weather Potential This Morning...

Convection is having issues getting going across the region as a
warm front lifts north across the region. A recent KGRB RAOB
sounding indicates this activity is fighting several capping
inversions and dry air aloft, which will probably not be overcome
overnight. Therefore, isolated to scattered thunderstorms are
anticipated this morning instead of a huge MCS rolling through the
region. This dry air and elevated warm layers should act to limit
the severe weather potential this morning.

Storms tonight and Tuesday Night...

Ample moisture and heat will provide the instability for storm
development through the upcoming week. However, lingering warm
air aloft will limit surface based storms at times. Thus, the
placement of the upper ridge and associated 'heat dome' over
eastern CONUS will remain the critical components to watch for
convective potential for our area. The first shortwave will cross
the upper Midwest tonight into Tuesday, but will largely initiate
in Minnesota. This system will then spread eastwards through the
evening, but capping over our area should help weaken storms as
they arrive. This will limit the best severe potential to our
west, with the Marginal Risk currently limited to portions of
central to north-central Wisconsin.

This scenario then repeats Tuesday evening as the next shortwave
arrives, but this time the ridge will be slightly more east,
possibly bringing the storms more into our area. That said, the
details of convection each day are muddy, largely depending on
when/where storms developed the previous day. That said, the upper
ridge is expected to continuing shifting eastwards through the
work week, bringing us into the line of fire of any shortwaves
along the upper ridge. Any storms will have the potential to be
strong to severe given the instability and moisture around. The
most likely hazard will be very heavy rainfall, especially if
storms repeat each day and soils become heavily saturated.

Dangerous Heat...

Active weather aside, the heat accompanying the upper ridge will
be a hazard itself. Dewpoints well into the 70s accompanied by
high temperatures into the 90s will bring heat indices well into
the upper 90s to mid-100s today and Tuesday. With the strong heat
signal over central Wisconsin and probabilistic guidance still
suggesting around 60-80% chance of exceeding 104 heat indices,
will keep the current headlines of an Extreme Heat Warning for
all of central to east-central Wisconsin. The most likely areas
to get the extreme heat will be central Wisconsin into the Fox
Valley, but also included the lakeshore areas for the inland
portions of the counties. There is also a signal on Tuesday that
southern Oconto and southern Marinette counties may reach Extreme
Heat Warning criteria Tuesday afternoon; however, will hold off on
any upgrades for these areas since overnight convection or clouds
could impact temperatures on Tuesday.

Those living along the shoreline of Lake Michigan and north of
Sturgeon Bay should see significantly lower impacts than those
further inland. North of the Extreme Heat Warning, heat indices
will remain just below advisory criteria during the afternoon,
lingering in the 95-99 range. However, overnight temperatures are
unlikely to drop below 75 in many areas, which typically means
little relief from the heat for those without shelter and means of
cooling. Given that this makes for a long stretch of heat, and
also that the forecast keeps overnight temperatures up even as
high temperatures drop slightly by Wednesday, decided to issue a
Heat Advisory for the rest of the region.

As we get into the mid to late week, heat indices should see a
minor drop, but temperatures are currently forecast to remain in
the upper 80s to lower 90s each day. The main complicating factor
for headlines during this period will be convective weather, as
any storms could provide some relief and lower the daytime high
in some areas. On the other hand, the forecast keeps heat indices
for most of the area above 70 through Friday, which would
compound heat fatigue effects for those without shelter as
mentioned above. Depending on how these convective trends and
clouds play out, an extension of heat headlines is not out of the
question.

4th of July Weekend...

Taking a peek into the 4th of July weekend, current trends keep
the dangerous heat across the region on Friday, then push the
warmest air to the south Saturday and Sunday as a semi-
stationary front remains across Wisconsin. This will come with a
downside, as there will be lingering chances for showers and
thunderstorms at times as the front becomes the focus for
convection as several shortwaves track along the zonal flow across
the western Great Lakes region. At this time the best window for
convection appears to be Friday afternoon and Friday night as well
as Saturday afternoon into Saturday night; however, given how far
out this forecast is this could easily move to a different periods
based on what happens earlier in the week. Although the risk for
severe weather is difficult to assess this far out, the warm,
moist airmass will provide instability, which means strong to
severe storms are certainly a possibility for the weekend.

Currently temperatures look to stay in the upper 80s to lower 90s
on Friday, then cool slightly into the 80s Saturday and Sunday.
Heat index values on Friday will still be well into the 90s, with
values possibly approaching 100, cooling into the lower 90s by
Saturday and Sunday. Despite the "cooler" temperatures, we will
be coming off a prolonged period of hot weather; therefore an
extension of warm temperatures through the weekend may have a
compounding effect.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1201 AM CDT Mon Jun 29 2026

Cloudy skies and very isolated showers and thunderstorms were
noted across the region late this evening as convection ahead of
an approaching warm front is having issues initiating across the
region. A recent KGRB RAOB sounding indicates this activity is
fighting several capping inversions and dry air aloft, which will
probably not be overcome overnight. Therefore, will lower chances
for showers and thunderstorms to PROB30 across all of the TAF
sites as the chances of seeing thunderstorms are not zero, but
they certainly are not likely per previous forecasts. Any
thunderstorms could drop conditions to MVFR/IFR if they hit a TAF
site. As the warm front lifts north on Monday, skies will clear
from south to north across the region.

Winds will generally be southeast 10 to 20 knots, shifting to the
south on Monday behind the warm front.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon today to 7 PM CDT Tuesday for WIZ005-
010>013-018>021-073-074.

Beach Hazards Statement from 4 AM CDT early this morning through
this evening for WIZ022-040-050.

Extreme Heat Warning from noon today to 7 PM CDT Tuesday for
WIZ022-030-031-035>040-045-048>050.
&&

DISCUSSION.....Kurimski
AVIATION.......Kurimski

Hazardous Weather Outlook
National Weather Service Green Bay WI
131 AM CDT Mon Jun 29 2026

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-300645-
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-
131 AM CDT Mon Jun 29 2026

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

.DAY ONE...Today and Tonight

An Extreme Heat Warning is in effect this afternoon and evening
for central and east-central Wisconsin as well as the lakeshore
counties. A Heat Advisory is in effect for northern Wisconsin.

There will be an increased risk of rip currents at Lake Michigan
beaches today and tonight.

Thunderstorms are possible across the region early this morning.
These storms are not expected to be severe.

There is a chance for strong to severe thunderstorms late
tonight across northern Wisconsin. The main hazards would be
damaging winds and heavy rainfall.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Multiple days of high heat and humidity along with very warm nighttime
lows will result in heat-related impacts much of the upcoming
week. An Extreme Heat Warning is in effect for central and east-
central Wisconsin as well as the lakeshore counties on Tuesday. A
Heat Advisory is in effect for northern Wisconsin.

There will be an increased risk of rip currents at Lake Michigan
beaches Tuesday and Tuesday evening.

Periodic chances for thunderstorms will last through much of next
week. There will be a risk for strong to severe storms Tuesday
and Tuesday night as well as Wednesday and Wednesday night. The
main hazards will be damaging winds and heavy rain.

Additional rounds of storms are expected Wednesday through the 4th
of July weekend. Though details are not yet known, the pattern
would support strong or severe storms.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed tonight.

LMZ521-522-541>543-300645-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
131 AM CDT Mon Jun 29 2026

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

.DAY ONE...Today and Tonight

Thunderstorms are possible this morning. Any thunderstorms would
pose a hazard to mariners.

Conditions hazardous to small craft are expected today and
tonight on Lake Michigan due to gusty southerly winds and building
waves.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Periodic chances for thunderstorms will last through much of the
upcoming week. Some of these storms could be strong or severe.
Any thunderstorm would pose a hazard to mariners.

Conditions hazardous to small craft are expected Tuesday and
Tuesday night on Lake Michigan due to gusty southerly winds and
building waves.

Kurimski

Special Weather Statement
National Weather Service Green Bay WI
210 AM CDT Mon Jun 29 2026

WIZ011-012-290745-
Forest WI-Florence WI-
210 AM CDT Mon Jun 29 2026

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL FLORENCE AND NORTH
CENTRAL FOREST COUNTIES UNTIL 245 AM CDT...

At 210 AM CDT, Doppler radar was tracking a strong thunderstorm 6
miles southwest of Whisker Lake Wilderness, or 28 miles northeast of
Crandon, moving northeast at 35 mph.

HAZARD...Wind gusts up to 50 mph and pea 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...
  Tipler around 210 AM CDT. Fern around 215 AM CDT. Whisker Lake
  Wilderness around 220 AM CDT. Florence around 230 AM CDT.

Other locations impacted by this strong thunderstorm include Lost
Lake Campground, Lasalle Falls and Commonwealth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4599 8866 4599 8867 4598 8864 4599 8862
      4602 8860 4601 8859 4602 8851 4599 8849
      4600 8846 4598 8842 4599 8838 4596 8833
      4596 8825 4595 8824 4595 8819 4591 8810
      4573 8847 4599 8876 4602 8869
TIME...MOT...LOC 0709Z 237DEG 32KT 4587 8850

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

JLA

Special Weather Statement
National Weather Service Green Bay WI
226 AM CDT Mon Jun 29 2026

WIZ011>013-290815-
Forest WI-Florence WI-Northern Marinette County WI-
226 AM CDT Mon Jun 29 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHERN MARINETTE...
SOUTHEASTERN FLORENCE AND EASTERN FOREST COUNTIES UNTIL 315 AM CDT...

At 226 AM CDT, Doppler radar was tracking a strong thunderstorm near
Goodman, or 30 miles east of Crandon, moving northeast at 35 mph.

HAZARD...Wind gusts up to 40 mph and half inch 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...
  Goodman around 230 AM CDT. Homestead around 240 AM CDT.

Other locations impacted by this strong thunderstorm include Dunbar,
West Bass Lake Campground, Aurora, Niagara and Spread Eagle.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4592 8811 4591 8810 4590 8811 4588 8810
      4587 8807 4582 8813 4581 8813 4579 8809
      4578 8805 4579 8804 4579 8799 4578 8798
      4577 8799 4576 8796 4576 8794 4573 8791
      4554 8840 4567 8851
TIME...MOT...LOC 0726Z 235DEG 30KT 4569 8829

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Eckberg

Special Weather Statement
National Weather Service Green Bay WI
331 AM CDT Mon Jun 29 2026

WIZ022-290930-
Door WI-
331 AM CDT Mon Jun 29 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHERN DOOR COUNTY UNTIL 430
AM CDT...

At 331 AM CDT, Doppler radar was tracking a strong thunderstorm 6
miles north of Egg Harbor, or 16 miles east of Marinette, moving
northeast at 20 mph.

HAZARD...Wind gusts up to 30 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...
  Chambers Island around 335 AM CDT. Eagle Bluff Light around 345 AM
  CDT. Ephraim around 350 AM CDT. Newport State Park around 415 AM
  CDT.

Other locations impacted by this strong thunderstorm include Fish
Creek, Peninsula State Park, Sister Bay, Rowleys Bay and Ellison Bay.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4512 8731 4511 8735 4508 8734 4518 8742
      4524 8731 4521 8728 4522 8721 4530 8714
      4534 8700 4536 8699 4521 8692 4516 8698
      4515 8695 4508 8732
TIME...MOT...LOC 0830Z 245DEG 18KT 4513 8730

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

JLA

Special Weather Statement
National Weather Service Green Bay WI
353 AM CDT Mon Jun 29 2026

WIZ013-290930-
Northern Marinette County WI-
353 AM CDT Mon Jun 29 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL MARINETTE COUNTY
UNTIL 430 AM CDT...

At 353 AM CDT, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Pembine, or 34 miles north of Marinette, moving
northeast at 30 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.

Other locations impacted by this strong thunderstorm include Miscauno
Island and Kremlin.

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 4546 8783 4561 8797 4571 8781 4570 8781
      4568 8778 4567 8778 4567 8782 4566 8783
      4565 8783 4562 8780 4561 8778 4560 8778
      4556 8779 4557 8783 4556 8783 4554 8780
      4551 8780 4550 8779 4547 8781
TIME...MOT...LOC 0853Z 236DEG 26KT 4556 8784

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

JLA