480
FXUS63 KGRB 111120
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
620 AM CDT Sun Oct 11 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Record or near-record highs are expected today and Monday.
  Inland temperatures are expected to soar into the upper 70s to
  mid 80s.

- There is a 50 to 90% percent chance for light rain across the
  region Monday afternoon into Tuesday morning. A couple rumbles
  of thunder will also be possible.

- Chances for more widespread soaking precip possible late next
  week (30-60% chance), with much cooler temperatures arriving
  next weekend.

&&

.DISCUSSION...
Issued at 1116 PM CDT Sat Oct 10 2026

With the region solidly under a very warm airmass, as evidenced by
850 mb temperatures in the upper teens, record to near-record
highs are expected to continue across the region Sunday and Monday
ahead of an approaching low pressure system. Although the windiest
conditions are behind us, gusty winds are still possible today and
less so on Monday as the pressure gradient becomes more baggy.

Light rain still looks on track to arrive late Monday afternoon
as transient shortwave and weak low pressure traverse the upper
Mississippi Valley. Current setup has a high PoP (50 to 90%) low
QPF look to it, as the parent airmass doesn`t look particularly
moist. As such, NBM probabilistic guidance only shows a 30 to
70% chance for receiving 0.25" of rain through Tuesday morning.
The best chance for the highest rainfall amounts are currently
across north-central Wisconsin (50-70% for 0.25" or more) where
the best dynamics and moisture will coincide for the longest
period of time. A rumble or two of thunder wouldn`t be out of the
question Monday evening as meager instability (~500 to 600 J/kg
MUCAPE) builds along the front, though any convective activity
would remain elevated with little to no impacts.

Next chances for widespread soaking precip arrive toward the end
of next week as a deepening surface low and closed upper trough
track from the central Plains into the Midwest. System currently
has a very winter-like appearance to it, especially with
potential phasing scenario at play if we are to believe the more
aggressive LREF ensemble clusters. However, there is still a lot
of variability this far out in the forecast period as there are
some model solutions that do not phase the system until it tracks
further east, which would mean little to no precipitation for our
area late next week. Whatever solution ends up panning out it does
look like next weekend will be a lot cooler as highs only reach
the 50s.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 619 AM CDT Sun Oct 11 2026

Sunny skies are expected for the first half of this TAF period
with high and mid clouds gradually increasing over the area from
the west late this afternoon through late this evening. A few low
clouds may drop into far north-central WI late tonight, but
confidence is low on their occurrence.

LLWS will linger over the next few hours at the central and
north-central WI TAF sites, ending by 14z Sun. After 14z Sun,
south winds will gust to 15-20 kts throughout the day followed by
another period of LLWS developing after 03z Mon at all TAF sites,
as southwest to west winds of 35-40 kts will be just above the
surface.

&&

.MARINE...
Issued at 1116 PM CDT Sat Oct 10 2026

Strong southerly winds will continue to result in conditions
hazardous to small craft on the Bay and Lake through Sunday
morning. Expect sustained winds of 15 to 25 knots, with a few
gusts to 30 knots possible. The threat for gales has largely
passed with this issuance. Waves of 2 to 4 ft on the Bay and 6 to
9 ft on the Lake will subside through the day on Sunday. Winds
and waves then subside Sunday morning as gradient winds ease up.

&&

.CLIMATE...
Issued at 1116 PM CDT Sat Oct 10 2026

Daily record and forecast high temperatures are shown below for
Sunday, October 11, and Monday, October 12:

High Temperatures for Sunday, October 11th:

              Record/Year(s)     Forecast
Green Bay:    83/2024               79
Wausau:       81/1928               82
Rhinelander:  81/1910,1928          81
Appleton:     82/1928,2024          80

High Temperatures for Monday, October 12th:

              Record/Year(s)     Forecast
Green Bay:    82/1918,2008          83
Wausau:       82/1995               84
Rhinelander:  81/1930,1995          82
Appleton:     81/1918,1943,2008     83.

&&

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

&&

$$

DISCUSSION.....Kurimski
AVIATION.......Kruk
MARINE.........Kurimski
CLIMATE........Kurimski

NWS GRB Office Area Forecast Discussion