178
FXUS63 KGRB 171923
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
223 PM CDT Thu Jul 17 2025

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Cooler and less humid conditions expected through Friday.
  Temperatures and humidity increase some over the weekend.

- An active pattern is expected Friday night through the middle of
  next week with periodic chances of showers and thunderstorms.
  Stronger storms and heavy rain are possible at times.

&&

.DISCUSSION...
Issued at 223 PM CDT Thu Jul 17 2025

Cooler and much less humid conditions prevailed this afternoon
as temperatures were only in the upper 60s to lower 70s.
Comfortable dewpoints in the middle 40s to middle 50s were
reported as well.

For tonight, the fair weather cumulus will disappear this evening
with mostly clear skies continuing overnight. Did add some patchy
fog to the forecast due to the recent rain yesterday and expected
clear skies and light winds tonight. An upper level disturbance
will move into far northern Wisconsin Friday afternoon, bringing a
chance of showers in this region. Little or no CAPE and poor
700/500mb lapse rates supportive of not adding thunder to the
forecast. The next chance for a widespread rainfall will be Friday
night into Saturday morning as a 500mb trough swings across the
western Great Lakes. The risk for severe storms at this point is
very low. High pressure prevails Saturday night through Sunday
night.

Beyond Sunday night, the westerlies will remain along the
U.S./Canadian border next week. With the expected weather
pattern, suspect there will be several thunderstorms complexes
moving across the central United States during this time frame.
Placement and timing of these complexes remains low as the models
continue to show differing solutions from run to run, and amongst
the GFS/Canadian/ECMWF solutions. If there was anyone time period
to focus at the moment, it would be Wednesday into Wednesday
night period for stronger storms and locally heavy rain. Will have
to wait and see how it plays out. Temperatures likely to be at or
above normal much of next week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 110 PM CDT Thu Jul 17 2025

MVFR cigs lingered at the MTW, ATW, and OSH TAF sites early this
afternoon while VFR conditions with FEW/SCT clouds with bases
between 3000 to 4000 ft AGL prevailed elsewhere. Anticipate the
lingering MVFR cigs to improve to VFR within the first hour or two
of this TAF issuance. The FEW/SCT clouds will lift into the
afternoon before dissipating this evening. Mostly clear skies are
expected overnight. A few spots in central and north-central WI may
see some patchy fog towards Friday morning, but confidence is not
high enough to include in this TAF issuance. Mid-level clouds will
begin to build into central and north-central WI Friday afternoon
ahead of an increasing chance for showers.

&&

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

&&

$$

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