864
FXUS63 KGRB 230356
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1056 PM CDT Thu Oct 22 2026

Forecast discussion for routine evening forecast issuance

.KEY MESSAGES...

- Dense fog into early Friday morning. Dense Fog Advisory until 9
  AM Friday much of northeast and east-central Wisconsin.

- Staying mild into the weekend, with high temperatures inland of
  Lake Michigan warming into the mid 60s to low 70s.

- Rain chances (20-40%) Saturday night over northern WI, and late
  Monday into Tuesday over central WI.

- Cooler start to next week, with highs mainly in the 50s.

&&

.DISCUSSION...
Issued at 1055 PM CDT Thu Oct 22 2026

Dense fog into early Friday morning...Lingering stratus from late
afternoon has begun to build down and expand as dense fog with
cooling of the evening. Expect dense fog overnight into early
Friday morning, expanding farther to the west, before dissipating
late in the morning. Dense Fog Advisory issued for most of northeast
and east-central WI, including the Fox Valley. Only expecting patchy
dense fog for central and north-central WI, so left those areas out
of the advisory for now. Repeat performance of dense fog does not
appear likely on Friday night as southerly flow begins to increase
just off the surface ahead of cold front tied to strong low crossing
Manitoba Canada. Lakeshore could still see patchy dense fog though.

Rain chances...Nothing to write home about, but there are a few
times at least isolated light rain may occur in parts of the area.
No widespread rain chances are in store though as strongest lift
will remain tied into stronger low pressure systems tracking
across Canada. Even so will be a few shortwave troughs/weak fronts
shifting across the western Great Lakes at times, thus not a completely
dry forecast. Most favored chances still in line for Saturday night
into Sunday morning over the north (20-30%), then Monday night into
Tuesday for especially central WI (20-40%). Beyond this, the weak
fronts crossing the region will keep small chances of rain through
late week with stronger cold front resulting in greater chances of
rain late Wednesday into Thursday. Even with the more frequent
chances rain seen compared to the relatively dry pattern of recent,
overall rainfall amounts look light, under even a half inch for the
entire time frame.

Next week temperatures...Cooling on the way, most notable Monday
and Tuesday as highs reach the 50s for most, but may stay in the
40s far north. A bounce back occurs with highs in the 60s again
ahead of the approaching front for Wednesday and Thursday. May
turn cooler again late next week as we head toward the end of the
month, but spread from 25th to 75th percentile on NBM is pretty
high, so there are still uncertainties on temps by that time.
Nighttime lows will be seasonable. Monday night lows do drop into
the upper 20s to low 30s across the north, though little impacts
are expected as the growing season has come to an end.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 637 PM CDT Thu Oct 22 2026

Stratus far northeast WI to lakeshore slowly expanding west. Thus
far, vsby are unrestricted, but with evening cooling do expect
that to change. By late evening, expect dense fog to develop with
cigs and vsby less than 1/2SM at times. The fog will be most
dense from the Fox Valley to the lakeshore, including GRB/ATW/MTW.
Conditions may drop below airport minimums at times. Patchy fog
possible elsewhere, down to IFR at times late tonight. Once the
fog forms, expect lower vsby to persist through 12-14z Friday,
with lingering stratus 14-16z Friday. VFR conditions should
return to the entire area on Friday afternoon. With high pressure
overhead, winds will be light under 10 kts through the TAF period.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM CDT Friday for WIZ011>013-019>022-
031-037>040-048>050-073-074.
&&

$$

DISCUSSION.....JLA
AVIATION.......JLA

NWS GRB Office Area Forecast Discussion