Green Bay, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

548
FXUS63 KGRB 041938
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
238 PM CDT Sat Jul 4 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Isolated showers and thunderstorms are expected this afternoon
  and evening, mainly across central and north-central WI.

- Seasonal summer temperatures are expected for the holiday
  weekend and into next week.

- Dry conditions early next week, with shower and thunderstorm
  chances (50-80%) returning mid-week.

&&

.DISCUSSION...
Issued at 233 PM CDT Sat Jul 4 2026

This afternoon through tonight...very little shower activity so
far this afternoon as clouds and northeast winds have keep the
atmosphere more stable, with the higher dewpoints and instability
residing to our south/west. Getting some good insolation how
across portions of central WI, where MLCAPEs are expected to climb
to 1500 J/kg during peak heating. This, combined with an
approaching weak shortwave, should kick off at least isolated
showers and a couple storms across central and north-central WI
late this afternoon and early evening. CAMs have continued to
trend downward with coverage, with better chances to our
west/south. Will carry 15-30% PoPs to cover the shower/storm
threat. With little deep-layer shear, any storm would be more
pluse-like and a slow mover, which could produce locally heavy
rain and brief gusty winds. Further north/east, the prevailing
north/northeast winds and limited instability should keep
conditions dry. The shower/storm activity will come to an end this
evening as daytime instability wanes after sunset. A little area
of moisture/elevated CAPE is forecast to advect in from Lower
Michigan overnight, which could trigger a shower over east-central
WI, but no impacts are expected and will hold PoPs under 15.

Some fog and low clouds may linger on/near Lake Michigan, mainly
south of Kewaunee this afternoon into tonight, where the higher
dewpoints reside. But with the drier northeast winds prevailing,
think the thicker, more widespread fog will stay over southern
Lake Michigan.

For Sunday...the weak mid-level shortwave/trough will reside over
the area, but with less instability, persistent northeast winds
ushering in drier air, and CAMs backing off on coverage, looks
like most spots will stay dry. Can`t rule out a stray shower west
of a Rhinelander to Wausau line, so will have some 15% PoPs there.

Next Week...models continue show upper-level ridging residing
over the area for Monday through Tuesday morning. This will result
in dry conditions for Monday and potentially through most of
Tuesday, but some afternoon showers possible over northern WI
Tuesday afternoon. The ridge breaks down as a shortwave and low
pressure system approach, with chances (50-80%) for widespread
showers and storms returning mid-week. Long range global ensembles
do show instability typical of early July during this time making
stronger storms possible; however, there is no signal of a higher
end severe event within the statistical suite of guidance.

Temperatures...Seasonable temperatures are expected Sunday with
highs ranging from the upper 70s to low 80s. Dewpoints will drop
into the 50s and low 60s on Sunday, making for a pretty pleasant
summer day. Temperatures look to be in to upper 70s and 80s for
most of the week, with dewpoints slowly climbing through mid-week.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 233 PM CDT Sat Jul 4 2026

Pesky IFR/MVFR clouds remained across portions of central and
east-central WI late this morning. These lower clouds should
continue to lift and mix out this afternoon, but additional
daytime cu will develop through the afternoon. Other mid and high
clouds will also spread across the region through Sunday. Mainly
dry conditions are expected through the remainder of the TAF
period. The exception would be the potential for isolated showers
and a few storms developing late this afternoon into this evening
over the central and north-central WI TAF sites. Confidence
remains low on these directly impacting the TAF sites and coverage
looks to remain pretty low, so continued PROB30 groups for
showers for now.

North to northeast winds of 5 to 15 kts are expected this
afternoon, becoming light and variable overnight, then
east/northeast on Sunday morning, mainly under 10 kts.

&&

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

&&

$$

DISCUSSION.....Bersch
AVIATION.......Bersch