767
FXUS63 KGRB 131136
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
636 AM CDT Tue Oct 13 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Chance for widespread soaking precip arrives late this week,
  though there is still some uncertainty regarding amounts and
  timing.

- Temperatures will cool through the week, bottoming out on Friday
  then slowly warming this weekend into early next week.

&&

.DISCUSSION...
Issued at 1145 PM CDT Mon Oct 12 2026

Showers and embedded thunderstorms will exit the region early
Tuesday morning as a low pressure system lifts northeast through
the western Great Lakes. Behind this departing low temperatures
will be a lot cooler Tuesday; ranging from around 60 across the
north to around 70 across east-central Wisconsin. Although the
weather is mainly expected to be dry until the next system arrives
later in the week, a weak mid level shortwave will bring a slight
chance (10-20%) for light showers Tuesday night.

A larger phasing system is expected towards the end of the week
as southern and northern streams merge. Phasing systems generally
have much uncertainty in terms of timing but some general
agreement has come into alignment with the most recent forecast
cycles. Rain will start sometime in the late morning to afternoon
hours on Thursday then cross the region into the overnight hours.
How long the system remains around on Friday remains uncertain
and will depend largely on whether the phasing occurs overhead or
to our east. After some possible showers Friday morning, things
look to dry out at least by Friday afternoon. Recent model runs
have backed off a bit on the snowflakes as the system winds down.
This system will also bring a period of windy conditions for
Friday, especially across the Door Peninsula.

Behind this departing low a large area of high pressure will build
back into the region, which will bring dry weather for the weekend
into early next week. The high will also allow temperatures to
slowly warm through early next week, as highs recover back into
the 60s.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 632 AM CDT Tue Oct 13 2026

Areas of MVFR or IFR CIGS will lift into the VFR category this
by early afternoon across much of the area. A period of gusty
winds to around 20 knots should ease later this morning into
the afternoon. VFR conditions will be ongoing early tonight,
but some guidance has MVFR CIGS moving back into the area
later tonight and linger into Wednesday morning. Confidence is
low if this would occur.

&&

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

&&

$$

DISCUSSION.....Kurimski
AVIATION.......Eckberg

NWS GRB Office Area Forecast Discussion