580
FXUS63 KGRB 251730
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1230 PM CDT Fri Sep 25 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Patchy fog development will be possible north and west of the
  Fox Valley late tonight into early Saturday morning.

- High pressure will maintain mostly dry weather through early
  next week.

- Next widespread rain chances arrive during the middle of next
  week.

&&

.DISCUSSION...
Issued at 1200 PM CDT Fri Sep 25 2026

A scattered fair weather cu field has begun popping as of early
this afternoon, though conditions remain mostly sunny with
temperatures warming into the upper 60s to low 70s. Clearing skies
and light winds may once again result in patchy fog after
midnight, though the setup remains conditional. Similar to this
morning, fog development will likely hinge on increasing cloud
cover early Saturday morning, which may hinder radiational
cooling. Will be worth monitoring given volatility over the past
couple of mornings.

Rain chances over the weekend continue to look rather pessimistic
as high pressure wins the battle, as it so often does in this
scenario. Models continue to show light rain splitting off to our
north and south as low pressure ejects into northern Canada,
leaving PoPs at a meager 15 to 20%. While a sprinkle or two
wouldn`t be out of the question over central or north-central
Wisconsin, expect most of the forecast area to remain dry.

Starting to see similar decreasing trend with rain chances during
the middle of next week as abundant low-level dry air remains in
place beneath Hudson Bay high. Chances for widespread rainfall
still look on track as PWATs approach 90th percentile, though
ensembles begin to flatten out the upper trough as it approaches
the Midwest and encounters sturdy omega ridge. As such, probabilities
for one inch of rainfall have been reduced to around 20 to 30%.
Additionally, better moisture return and forcing look to remain
off to our south, which would mean more of a glancing blow to our
southern tier of counties. All in all, signs still point toward a
decent stratiform rain setup, though excessive rainfall potential
remains in question due to prolonged duration and current drought
status. Worth mentioning is that predictability remains fairly
low this far out in the forecast period, so there is still time
for things to change.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1200 PM CDT Fri Sep 25 2026

Low stratus over central and east-central Wisconsin continues to
erode this afternoon, leaving a SCT fair weather cu field
developing from north to south in its wake. Patchy fog will once
again be possible late tonight into early Saturday morning,
though will hinge on cloud development similar to this morning.
Highest confidence in fog development will be further north, so
have retained TEMPO group for reduced vsbys in the RHI TAF. Mid
and high clouds then return Saturday afternoon.

Southeast winds remain under 10 knots through this afternoon,
becoming light and variable overnight.

&&

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

&&

$$

DISCUSSION.....Goodin
AVIATION.......Goodin

NWS GRB Office Area Forecast Discussion