NWS-Green Bay Forecast Discussion
FXUS63 KGRB 040250
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
950 PM CDT Fri Jul 3 2026
Updated aviation portion for 06Z TAF 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 06Z TAF Issuance
Issued at 844 PM CDT Fri Jul 3 2026
Showers/storms ongoing late this evening will continue to
diminish in coverage overnight, though may linger into Saturday
morning. Brief lowering of cigs to MVFR will be possible if a
shower or storm moves directly over a terminal. Remnant moisture
near the surface may then result in patchy fog development across
the forecast area late tonight into Saturday morning, though
confidence remains low in fog coverage and density. Will limit any
reductions in vsbys to MVFR. Another round of SCT showers (50 to
70% chance) and storms (30 to 50% chance) is expected Saturday
afternoon, though conditions should remain VFR. Highest
confidence for thunder chances are over central Wisconsin.
Winds will start out of the south/southwest, eventually veering to
east/northeast behind the lake breeze Saturday morning. Prevailing
winds should remain light, though gusty outflow winds will be
possible with any storms on Saturday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....GK
AVIATION.......Goodin