Green Bay, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

268
FXUS63 KGRB 060450
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1150 PM CDT Fri Sep 5 2025

Updated aviation portion for 06Z TAF issuance

.UPDATE...
Issued at 936 PM CDT Fri Sep 5 2025

No major changes to forecast late this evening. Latest models,
especially the HRRR and RAP, still point to expansion of light
showers and/or sprinkles over northeast WI late tonight (3am-6am)
as forcing increases with shortwave approaching from the west.
Already incorporated these trends into earlier update this
evening. At the high-end, only looking at 0.05-0.10 inch of rain,
but for most probably only will be a trace to a few hundredths.
Winds are diminishing, with main exception over northern Door
County/Washington Island with flow off Bay of Green Bay.

Temps still on track from earlier, with clouds and some wind limiting
risk of any frost over the north even if temps can manage to drop
into the mid to upper 30s. Readings of 38-40f are most likely though.

&&

.KEY MESSAGES...

- Scattered to isolated showers through Saturday, with the greatest
  chances in north-central Wisconsin.

- Near-record cold maximum temperatures are possible through this
  weekend. Frost potential Sunday and Monday morning. Moderating
  temperatures early next week, but remaining below normal.

&&

.DISCUSSION...
Issued at 222 PM CDT Fri Sep 5 2025

Cyclonic flow, gusty westerly winds, along with light showers and
sprinkles will continue this evening as a shortwave, seen on water
vapor imagery over South Dakota, tracks east through Wisconsin.
Winds will ease a bit later tonight behind the departing shortwave
as showers and sprinkles become less numerous. The best chance for
showers will be across north-central Wisconsin tonight with added
moisture from Lake Superior.

Additional shortwaves will provide more opportunities for light
rain showers and sprinkles Saturday into Saturday evening. An
upstream high pressure system will build in from the west, which
will bring a drying trend to the region late Saturday night into
Sunday.

The high will track east Sunday night, allowing for return flow on
Monday. An approaching cold front will bring the next chance for
showers and thunderstorms to the region from Monday night through
Tuesday evening as it slowly tracks through the area. High
pressure should then keep the rest of the week dry.

Temperatures/Frost Potential...An abnormally cold airmass will
continue to reside over the area through the weekend, resulting in
well below normal temperatures. Several sites are expected to set
new record low maxes for today, with additional records
potentially in jeopardy on Saturday. See the climate section for
more details about records. The addition of the surface high
pressure system moving into the region Sunday into Monday, may
allow for a couple periods of frost development in portions of the
region Sunday morning and Monday morning with low temperatures
forecast in the mid 30s to low 40s. The return flow early next
week will allow temperatures to rise into the 60s and low 70s, but
remain below normal.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1150 PM CDT Fri Sep 5 2025

Scattered showers or sprinkles are expected through late tonight.
The greatest coverage for light rain is expected over northeast
WI, so have continued to carry mention at GRB/ATW/MTW. No reduction
to vsby is expected. CIGS will mainly be VFR through the period at
all TAF sites, though RHI will see occasional MVFR cigs tonight.

Westerly winds 5 to 10 kts will increase again Saturday morning
with gusts to around 15 knots.

&&

.MARINE...
Issued at 939 PM CDT Fri Sep 5 2025

Westerly winds are still gusting to 25 kts over the bay and near
Death`s Door. Winds have diminished elsewhere. A Small Craft
Advisory remains in effect for the bay and nearshore waters
north of Sturgeon Bay through midnight. Small Craft Advisory has
been cancelled early over the rest of the Lake Michigan nearshore
waters. Beyond midnight, expect winds and waves to remain below
headline criteria for the rest of the weekend.

&&

.CLIMATE...
Issued at 222 PM CDT Fri Sep 5 2025

The unseasonably cold airmass will bring additional chances of
setting record low maximum temperatures on Saturday (9/6). Here
is a look the current records and forecast values for Green Bay,
Rhinelander, and Wausau.

 Green Bay

Date           Record Low Max       Forecast High
----           --------------       -------------

9/6              58F(1965)               60F

 Rhinelander

Date           Record Low Max       Forecast High
----           --------------       -------------

9/6              55F(1956)               56F

 Wausau

Date           Record Low Max       Forecast High
----           --------------       -------------

9/6              56F(1965)               58F.

&&

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

&&

$$

UPDATE.........JLA
DISCUSSION.....Kurimski
AVIATION.......JLA
MARINE.........JLA
CLIMATE........Kurimski