939
FXUS63 KGRB 031828
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
128 PM CDT Fri Jul 3 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Isolated to scattered showers and thunderstorms are expected at
  times this afternoon into this evening, mainly across northern
  WI.

- Additional chances for showers and thunderstorms are expected
  throughout the holiday weekend.

- Seasonal summer temperatures are expected for the holiday
  weekend.

&&

.DISCUSSION...
Issued at 126 PM CDT Fri Jul 3 2026

Rest of Today...A subtle short-wave passing over the region along
with remnant outflow boundaries floating around has lead to an area
of scattered showers across central and east-central WI that will
continue through this afternoon. RAP analysis does show enough weak
elevated instability for these showers to produce isolated lightning,
however, radar and satellite trends over the past hour have shown no
imminent signs of lightning. Another area of showers and storms is
possible across northern WI this afternoon and evening as a lake
breeze moves south of Lake Superior. Again, there is enough
instability to support lightning, however, with a lack stronger deep
layer shear don`t expect any stronger more organized storms to
develop.

Shower and Storm Chances This Weekend...Lingering boundary
(lake/outflow) scattered across the forecast area Saturday morning
may provide the focus for scattered showers with embedded
thunderstorms. However, confidence in showers at any given location
is low so have limited PoPs through the morning to 20-40%.
Precipitation chances do increase into the afternoon and evening as a
middle level short-wave, tracks over the region. Highest
precipitation chances (50-70%) are across central WI Saturday
afternoon with lower chances (30-50%) closer to the lakeshore and
into north and northeast WI. MUCAPE values of 800-1200 J/kg will
make isolated thunderstorms possible during the afternoon and
evening, however, with weak deep layer shear the chance for stronger
organized storms is low (~10%). CAM ensembles point towards a second
trailing shower-wave pass over the region Saturday night into Sunday
leading to lingering shower and thunderstorm chances (20-40%)
through Sunday morning before precip chance dry up Sunday afternoon.

Dry to Start Next Week...Global ensembles and longer ranger ML
models are in generally good agreement than an upper ridge will be
building over the upper Midwest during the beginning of next week.
This will bring largely dry conditions to the forecast area Monday
and Tuesday. As the aforementioned ridge pushes east during the
middle of next week large scale troughing is expected to develop.
This will lead to increasing chances for showers and thunderstorm
Wednesday into Thursday. 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.

Temperature Trends...This weekend temperatures are forecast to trend
near seasonal averages with highs in the upper 70s to low 80s
Saturday and Sunday.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1244 PM CDT Fri Jul 3 2026

A mix of VFR and MVFR conditions exist across the forecast area
early this afternoon as scattered areas of status are lingering
below an area of mid-level clouds. There is also an area of
expanding showers across central WI that may impact all TAF sites,
expect RHI through about 22Z. Chance for -TSRA at RHI does exist
later this afternoon 22Z-04Z with a round of storms expected to
develop along a lake breeze sinking south off Lake Superior.
Scattered showers and storms may persist into the overnight hours,
but should diminish in coverage. As precipitation comes to an end
areas of fog are possible across the region, however, confidence in
fog at any of the TAF sites is low so have limited vsby impacts to
MVFR with this TAF issuance.

For Saturday a mix of MVFR and VFR conditions is expected as another
round of scattered showers is expected through much of the day.

&&

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

&&

$$

DISCUSSION.....GK
AVIATION.......GK

NWS GRB Office Area Forecast Discussion