079
FXUS63 KGRB 121206
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
706 AM CDT Mon Oct 12 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

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

- There is a 30 to 90% percent chance for light rain across the
  region this afternoon into Tuesday morning, highest chances
  north. 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 1131 PM CDT Sun Oct 11 2026

Temperatures will continue to be at or near-record territory on
Monday as the area remains in the warm sector of a low pressure
system approaching from the central Plains. The only limiting
factor on Monday will be mid and high level clouds streaming in
from the west. However, models do clear out these clouds across
central and east-central Wisconsin by the afternoon. Wind are not
expected to be as gusty, with winds of 10 to 20 mph expected.

Precip chances...The best chance for rain still appears to be
Monday evening as the main surface low tracks through northern
Wisconsin coincident with the mid level shortwave tracking through
the region. The best chances (60-90%) look to be across northern
Wisconsin where the best moisture will reside with much lower
chances (30-40%) across central and east-central Wisconsin as a
dry slot tracks through the area. While the probability of
exceeding 0.25" of rain has risen to 50-80% across the north,
chances are fairly meager south of highway 20 at 10-30%. 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
into the weekend as arctic high brings below normal temperatures
from the Plains to the Midwest as well as a return to dry
conditions. 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 12Z TAF Issuance
Issued at 706 AM CDT Mon Oct 12 2026

High and mid clouds will remain overhead through mid-morning,
excluding the far north where clouds are expected to remain in
place for this TAF period. Clouds will then increase again early
this evening ahead of a surface low pressure system. During this
time, there will be a chance of rain showers across all TAF sites
from west to east roughly between 23z Mon to 05z Tue. A few
rumbles of thunder are also possible. The highest confidence for
showers and storms is at RHI, where a TEMPO group is included.
However, due to lower confidence in timing and placement, PROB30
groups were used for SHRA at the other TAF sites, with a PROB30
group at RHI after 03z Tue. As the low pressure system moves
overhead following the rain chances, cigs will drop to IFR/LIFR
at RHI and gradually to MVFR/IFR at the central WI TAF sites and
potentially to MVFR at GRB through the remainder of this TAF
period.

Southwest winds under 10 kts are expected through early this
evening before winds gradually turn southeasterly or variable.

&&

.CLIMATE...
Issued at 1131 PM CDT Sun Oct 11 2026

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

High Temperatures for Monday, October 12th:

              Record/Year(s)     Forecast
Green Bay:    82/1918,2008          83
Wausau:       82/1995               83
Rhinelander:  81/1930,1995          79
Appleton:     81/1918,1943,2008     82.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion