629
FXUS63 KGRB 271148
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
648 AM CDT Thu Aug 27 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Patchy ground fog this morning in north-central WI, and possibly
  again late tonight in central and north-central WI.

- Next chance of showers and storms arrives late Friday night into
  Saturday, continuing into early next week. Details are uncertain
  for greatest rain potential and storm intensity.

&&

.DISCUSSION...
Issued at 225 AM CDT Thu Aug 27 2026

This morning...Dry and mostly clear skies prevailed across the
region early this morning. However, patchy, shallow ground fog began
to develop in north-central WI with some locations reporting
visibilities as low as 1/4 mile. Anticipate the lowest visibilities
occurring in valleys and low areas. Any fog will lift soon after
sunrise.

Today through Friday...Non-impactful weather is expected during this
forecast period as high pressure and mostly dry conditions are
forecast. There are two possible exceptions to this: first, there is
a very low chance of showers (up to 20%) in far northeast WI late
this evening through tonight from a weak, moisture starved backdoor
cold front, and two, a few showers (less than 15% chance) may
develop off of lake and bay breezes Friday afternoon.

There is also a signal for fog development late tonight into Friday
morning with the high pressure overhead. However, fog development
may be limited depending on how much cloud cover there is from the
backdoor cold front. For now, it appears locations in central and
north-central WI would be most susceptible to seeing at least patchy
fog development.

Rest of the Forecast...Low forecast confidence is present for the
details revolving around this weekend`s precipitation chances due to
timing and placement differences. But, it appears the first chance
of showers and storms looks to arrive late Friday night into
Saturday morning, with periods of showers and storms continuing
through early next week. Ensembles are in decent agreement with the
instability peaking on Sunday and Monday, leading to a greater
potential for thunderstorms, perhaps strong/severe, during this
time. But, given the low forecast confidence in the finer details,
will continue to monitor. Regardless of the storm severity
potential, this set up could bring periods of heavy rainfall to the
drought ridden forecast area.

Temperatures...Through the start of the weekend, high temperatures
will hover around normal with values mainly in the 70s to low 80s.
For tonight, lows will range from the mid 40s to mid 50s. But
depending on how much cloud cover spreads over the area, a few
locations across the Northwoods could see lows drop in the upper
30s. Late this weekend into early next week, temperatures will warm
above normal with highs in the low to mid 80s, and dew points
increasing into the 60s, and perhaps low 70s for some spots in east-
central WI.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 647 AM CDT Thu Aug 27 2026

Besides some lingering patchy ground fog producing vsbys as low
as 1/4 SM in north-central WI, clear skies prevailed across the
region this morning. A cu field, with VFR cigs, is expected to
develop this afternoon across all TAF sites. Cannot rule out the
potential for a few sprinkles, but no impacts are expected. Mid-
level clouds and a couple sprinkles will continue overnight
mainly in far northeast WI. Meanwhile, there are some signs for
patchy ground fog to redevelop late tonight into Friday morning
in north-central and central WI, but cloud cover may limit fog
development. Have only included a TEMPO group at RHI for lower
vsbys.

NW winds at 5 to 10 kts are expected today, but will turn easterly
during the afternoon at the east-central WI TAF sites from a lake
breeze. Winds will become light and variable overnight.

&&

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

&&

$$

DISCUSSION.....Kruk
AVIATION.......Kruk

NWS GRB Office Area Forecast Discussion