579
FXUS63 KGRB 111730
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1230 PM CDT Sun Oct 11 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Record or near-record highs are expected this afternoon, and
  again Monday afternoon. Inland temperatures are expected to read
  in the upper 70s to mid 80s.

- There is a 50 to 80% 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 arrive late this
  week, though there is still much uncertainty. Much cooler
  temperatures next weekend.

&&

.DISCUSSION...
Issued at 1200 PM CDT Sun Oct 11 2026

Temperatures early this afternoon have warmed into the mid to
upper 70s inland of Lake Michigan under clear skies. Essentially a
rinse and repeat of yesterday, where several locations are already
within a few degrees of record highs with several hours of warming
and mixing yet to occur. Expect additional records to be broken by
late this afternoon, and again Monday afternoon. Have continued
the trend of blending in NBM 90th percentile to nudge highs up by
a couple degrees. Less confidence in highs being broken Monday
afternoon since there will be some mid clouds around, though there
will be decent windows for clearing. Otherwise, southerly winds
remain breezy (though not as strong as yesterday), with obs
showing gusts to around 20 mph.

Precip chances... CAMs have trended slightly earlier with the
arrival of light rain on Monday, with the cold front now
encroaching on north-central Wisconsin early Monday morning. As
such, some models generate light QPF over the north Monday morning
along the front. However, the main push of precip (50 to 80%
chance) looks to move through late Monday afternoon through Monday
night with support from transient upper shortwave. Front still
looks moisture-starved for the most part, so probabilities for
receiving 0.25" of rain remain at a meager 20 to 50% north of Hwy
29. Embedded non-severe storms remain possible as corridor of
elevated instability (~600 to 800 J/kg) develops along the front,
though any convective activity would remain elevated.

No further clarity provided for end of week system as ensemble
clusters remain divided on synoptic pattern evolution. As it so
often is, phasing potential remains a major source of uncertainty
as some models show northern and southern streams phasing over
the Great Lakes, while some show this occurring further east.
As it stands now, still looks on track to bring us our next
widespread precip chances, though this is subject to change as
models hopefully get a better handle on the upper pattern.
Consistent signal also remains for the first flakes of the season
mixing in across the north along the back edge of the system.

Outlook... More fall-like pattern sets up at the end of the week
as arctic high brings below normal temperatures from the Plains to
the Midwest. 850 mb temperatures will tank to well below 0C as
northwest flow ramps up, resulting in high temperatures reading in
the 50s for most. Frost/freeze setup looks likely from central to
east-central Wisconsin as we approach the end of the growing
season.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1200 PM CDT Sun Oct 11 2026

Expect sunny skies to continue through this afternoon, with mid
clouds increasing from the northwest late this evening and
overnight. Some low clouds (MVFR to high-end IFR) may drop into
northern Wisconsin late tonight into Monday morning, though remain
uncertain whether or not they will reach RHI. Have included BKN
deck at 1k ft for the time being.

Expect southerly winds to gust to around 20 knots at all terminals
through this afternoon. Winds then subside overnight, giving way
to LLWS concerns after 00Z as 850 mb winds increase. LLWS ends
from northwest to southeast by 12Z Monday.

&&

.MARINE...
Issued at 1200 PM CDT Sun Oct 11 2026

Winds and waves are expected to remain elevated along the nearshore
waters of Lake Michigan through late this afternoon due to a
tight pressure gradient over the eastern half of the state. Gusts
to 25 knots will remain possible during this time, with waves 4 to
7 ft. Waves then subside after 00Z as gradient winds ease up, after
which marine hazards will come to an end.

&&

.CLIMATE...
Issued at 1200 PM CDT Sun Oct 11 2026

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

High Temperatures for today, October 11th:

              Record/Year(s)     Forecast
Green Bay:    83/2024               80
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          81
Wausau:       82/1995               83
Rhinelander:  81/1930,1995          80
Appleton:     81/1918,1943,2008     81.

&&

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

&&

$$

DISCUSSION.....Goodin
AVIATION.......Goodin
MARINE.........Goodin
CLIMATE........Goodin

NWS GRB Office Area Forecast Discussion