Granite Peak

000
FXUS63 KGRB 010007
AFDGRB

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

Updated aviation portion for 00Z TAF 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 00Z TAF Issuance
Issued at 707 PM CDT Sat Oct 31 2026

An IFR status deck has developed over northern WI early this evening 
and will likely linger through the night as it continues to low near 
LIFR at RHI. Within the status deck scattered light rain showers 
continue to drift northeast across northern WI. Based on recent 
radar trends these showers should remain north and east of most of 
the TAF sites, except RHI where a brief shower or two will remain 
possible through about 03Z. CAMs do show some fog developing tonight 
mainly across northern WI, however, given the ample cloud cover 
confidence is too low to restrict vsbys to less than MVFR conditions 
at AUW, CWA, and RHI tonight.

Sunday the low clouds will likely linger through at least mid-
morning across much of the region before gradually stating to clear, 
except across north-central WI where IFR/MVFR cigs may linger into 
the afternoon. Light south to southeast winds are expected through 
the TAF period.

&&

.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.......GK
MARINE.........Kurimski