509
FXUS63 KGRB 010500
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1200 AM CDT Sun Nov 1 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Unsettled conditions much of next week, with widespread showers
  (+90%) and gusty winds Monday afternoon through Wednesday,
  peaking Monday night into Election Day.

- 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 1113 PM CDT Sat Oct 31 2026

A few isolated showers are lingering along the WI/UP border and
across northern Door Co late this evening. As the forcing driving
these showers shifts east overnight expect a return to dry conditions
to finish out the weekend. Tonight patchy areas of fog will
likely develop, mainly across central WI where partial clearing of
a low stratus deck occurs. However, with the increasing cloud
cover early Sunday don`t expect fog to become particularly dense
or widespread.

Next round of impactful will arrive Monday afternoon/evening and
sticks around into at least Thursday as a moisture rich low
pressure system lifts out of the Central Plains. Rain becomes
likely (+90%) Monday night into Tuesday with the initial surge of
moisture and forcing. Then chance/likely PoPs (40-70%) will
continue through Wednesday, before finally taper off 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 70-90% 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 06Z TAF Issuance
Issued at 1200 AM CDT Sun Nov 1 2026

Weak warm advection continues across the region between low
pressure over the northern Plains and high pressure off the east
coast. MVFR ceilings continue to shift north across far northern
WI early this morning. Meanwhile, broken to overcast ceilings 7-9
kft AGL extend from central WI to the central Mississippi Valley,
with some embedded breaks in the overcast as well. Where skies
partially clear, dense fog has developed over parts of north-
central WI in the moist boundary layer.

Potential will be there for patchy dense fog to develop early this
morning over north-central WI, which could impact RHI. Added a
LIFR tempo group through 14Z Sun. MVFR to IFR visibilities will
also be possible at AUW and CWA.

Elsewhere, time-height cross-sections show broken ceilings around
7 kft AGL to persist through much of the taf period.

&&

.MARINE...
Issued at 1113 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.....GK
AVIATION.......MPC
MARINE.........GK

NWS GRB Office Area Forecast Discussion