Tornado in Wisconsin, July 19, 2025

Area Forecast Discussion
National Weather Service Green Bay WI
303 PM CDT Sat Jul 19 2025

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Marginal short-term severe weather threat for the Fox Valley through
  this afternoon.

- Dry weather from later this evening through Monday night. Smoke
  from the Canadian wildfires is expected to reach the surface at
  times Sunday into Monday.

- An active pattern is expected from Tuesday through Thursday,
  with periodic chances of showers and thunderstorms. Strong
  storms and heavy rain will be possible at times.

&&

.DISCUSSION...
Issued at 303 PM CDT Sat Jul 19 2025

A weak cold front extended from around Marinette to Wisconsin
Rapids this afternoon. Scattered showers and storms were
developing near and ahead of the front, where MLCAPE had
increased to 600-800 j/kg, and there was modest upper forcing from
the RRQ of a jet. This convection has been struggling to
strengthen, possibly due to very dry air above 700 mb and some
weak MLCIN. While severe storms are not imminent, cannot rule
out a severe storm or two, as deep layer shear remains quite
strong; 40 to 45 knots. Any severe threat should wane by 5 pm to
6 pm, though a few showers or a storm could linger into the early
evening.

High pressure brings dry and pleasant conditions for the rest of
tonight through Monday night. Areas of fog may impact northern WI
late tonight.

Smoke from Canadian wildfires will overspread the forecast area
tonight into early Sunday. While this initial surge should be
aloft, there is increasing potential for surface-based smoke on
Sunday, which will arrive in northern WI mid-morning Sunday and
spread south across the rest of the forecast area by late
afternoon. This smoke is expected to last through Sunday night,
and at least into Monday morning. Have continued to address this
by raising sky cover to at least 35 percent starting tonight, and
mentioning areas of smoke in the forecast during surface-based
impacts Sunday into Monday morning.

Zonal flow sets up across the region for the rest of the work
week, with very warm and more humid conditions returning to the
forecast area. There is support for a few rounds of convection
during the period, as a warm front lifts toward the region
Tuesday into Wednesday, followed by a cold frontal passage
Wednesday night into Thursday. Timing and location of individual
disturbances (possibly convectively-induced MCVs) in the fast flow
aloft will be very difficult, so details on pop trends will be
hard to pinpoint. In addition, there may be some capping/
convective inhibition that will limit the extent of convective
development. During this mid-week period, CAPE is expected to
increase to 2-4K j/kg, so a period or two of severe storms could
occur. In addition, with PWATs increasing to around 2 inches and
surface dew points rising into the middle 60s to middle 70s, heavy
rainfall will also be a possibility. Look for highs to reach well
into the 80s, with potential for lower 90s in C/EC WI on
Wednesday. Heat indices could reach into the 90s to around 100 on
Wednesday.

Once the slow-moving cold front exits later in the work week,
quieter conditions should return, though warm temperatures will
likely persist into the weekend.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1228 PM CDT Sat Jul 19 2025

A weak cold front is expected to bring scattered thunderstorms
this afternoon into early this evening. Some of the stronger
storms could produce strong gusty winds, hail and very low
visibilities at times due to heavy rain. The showers and storms
should end across the area by early to mid evening. Behind the
cold front, MVFR and some IFR CIGS are expected to spread
southward into central and east-central Wisconsin. Overnight,
areas of fog are expected, especially from the 06z-13z Sunday
time period across northern Wisconsin. Fair weather cumulus
clouds expected to develop late Sunday morning and continue
through the afternoon. Cloud heights should start out between 2-3
thousand feet and then rise to 4-5 thousand feet during the
afternoon.

KOSH - The chances of thunderstorms will be on the increase
after 19z, peaking in the 22z Sat to 00z Sun time period.
Gusty winds, hail and low visibilities due to heavy rain are
possible in the strongest storms. CIGS at times this afternoon
will be in the MVFR category due to the storms. The main question
for this evening is will the low clouds behind the cold front
linger through the evening into early Sunday morning. With the
18z TAF issuance, did linger a MVFR deck into early Sunday morning
before skies clear. West winds will veer north this afternoon,
and then to the northeast this evening.

&&

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

&&

DISCUSSION.....Kieckbusch
AVIATION.......Eckberg

Hazardous Weather Outlook
National Weather Service Green Bay WI
321 PM CDT Sat Jul 19 2025

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-202030-
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-
321 PM CDT Sat Jul 19 2025

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

.DAY ONE...Rest of this Afternoon through Tonight

There is a chance of thunderstorms across central and east central
Wisconsin for the rest of the afternoon. A few strong to severe
storms with gusty winds and hail are possible through 5 pm or 6 pm.

.DAYS TWO THROUGH SEVEN...Sunday through Saturday

Smoke from the Canadian wildfires should reach the surface Sunday
through Monday morning, which may lead to poor air quality and
locally reduced visibilities across the region.

Periodic thunderstorms are possible through the middle of next
week, especially from Tuesday through Thursday. It is too early
to determine specific details concerning timing and location,
but strong storms and heavy rainfall will be possible during this
period.

Very warm conditions are possible during the middle of the week,
especially on Wednesday, when heat indices may reach into the 90s
to around 100 range.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to report any wind damage or hail to the
National Weather Service in Green Bay.

LMZ521-522-541>543-202030-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
321 PM CDT Sat Jul 19 2025

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

.DAY ONE...Rest of this Afternoon through Tonight

Thunderstorms are possible for the rest of the afternoon,
especially south of Sturgeon Bay. Any thunderstorms could pose a
hazard to mariners.

.DAYS TWO THROUGH SEVEN...Sunday through Saturday

Periodic thunderstorms are possible through the middle of next
week, especially from Tuesday through Thursday.

Kieckbusch