643
FXUS63 KGRB 311744
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1244 PM CDT Sat Oct 31 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Spotty light rain and sprinkles (30-60% chances) for Halloween.
  Rainfall amounts less than 0.10 inch.

- Unsettled conditions much of next week, with widespread showers
  (70-95%) and gusty winds Monday afternoon through Wednesday,
  peaking Monday night into Election Day.

- Shower chances (10-20%) lingers Thursday into Friday.

- The probability of 48-hour rainfall totals over 1" from Monday
  afternoon through Wednesday afternoon range from 60-90% north
  and west of the Fox Valley to 40-60% over Fox Valley east to
  Lake Michigan.

- Above normal temperatures continue through next week.

&&

.DISCUSSION...
Issued at 1243 PM CDT Sat Oct 31 2026

An area of light showers and sprinkles continues across central
Wisconsin, associated with mid-level warm air advection. This
activity will lift north through the evening across north-central
Wisconsin and become more widespread as better moisture arrives
from the south. Abundant dry air in place and weak forcing will
limit the amount of rain that falls across the region, with less
than one tenth of an inch expected. High pressure then builds
back in on Sunday, bringing a return to dry conditions across the
region to finish the weekend.

A slow moving, moisture-laden system arrives Monday afternoon/
evening and sticks around into at least Thursday. Rain is likely
Monday night into Tuesday (80-95%) with the initial surge of
moisture and forcing. Then chance/likely PoPs will continue into
Wednesday, then taper off on Thursday as the system finally exits
to our east. Another system lifting north at the end of next week
could continue to rain chances into Friday; however, this is less
certain as the models differ in how far west this system makes it.

Chances for exceeding 1 inch of rain Monday Night through Tuesday
has increased a bit to 60-90% north and west of the Fox Valley
with 40-60% over Fox Valley east to Lake Michigan. The probability
for 2 inches or more is also a respectable 30-60% across central
and north-central Wisconsin during this same period. This set up
appears to look like a soaking rain at times. Some elevated
instability and impressive dynamics with the initial WAA surge
Monday night into Tuesday to include some thunder, especially
across central and north-central Wisconsin.

Temperatures will be above normal through the middle of next week
with temperatures cooling off behind the large system at the end
of the week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1127 AM CDT Sat Oct 31 2026

High pressure centered over the eastern Great Lakes will shift
east as a storm system moves northeast across the central Plains.
Deeper moisture ahead of this system will continue to gradually
shift northeast and across Wisconsin this afternoon as evidenced
by lowering ceilings and light rain showers moving across parts of
central and northeast WI. Most shower activity should stay to the
north and west of the east-central WI TAF sites (GRB/ATW/MTW). No
impacts to visibility are expected.

MVFR CIGs will arrive to AUW/CWA/RHI this afternoon. IFR CIGs are
expected at RHI starting this evening with a period of these
lower conditions possible at AUW/CWA later tonight. VSBYs may
also fall to MVFR in mist this evening as well; however,
confidence is lower for these conditions. Spotty light rain
showers and sprinkles will be possible through the day but little
to no impacts are expected. Kept the PROB30 north and west of the
Fox Valley and removed the chance for the east-central WI TAF
sites this afternoon. These low conditions should clear the
central WI TAF sites Sunday morning but linger at RHI through
midday Sunday.

&&

.MARINE...
Issued at 1243 PM CDT Sat Oct 31 2026

A slow moving low pressure system will move across the Great
Lakes Monday night into Wednesday morning, bringing gusty south to
southeast winds and large waves on the bay and Lake Michigan. A
Small Craft Advisory will likely be needed. A few gale force gusts
are possible Tuesday on Lake Michigan.

Winds will shift to the north on Thursday, possibly gusting to
near 25 kts as the system departs to the east.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion