973
FXUS63 KGRB 051130
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
630 AM CDT Mon Oct 5 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Frost Advisory remains in effect for north-central and far
  northeast Wisconsin until 8 AM this morning.

- Breezy southwest winds gusting 25 to 35 mph are expected to
  create hazardous marine conditions Tuesday morning through early
  Wednesday morning. Marine headlines have been issued.

- Patchy frost will be possible over far northern Wisconsin
  Thursday and Friday nights with low temperatures in the mid 30s.

&&

.DISCUSSION...
Issued at 130 AM CDT Mon Oct 5 2026

Frost/freeze... Temperatures have been slow to fall after sunset
with light winds and scattered mid clouds around, with readings
in the upper 30s to low 40s early this morning across headline
areas. However, with several hours yet for cooling to occur,
current thinking is that Frost Advisory remains on track. No
headline changes or upgrades are planned with only a 20 to 40%
chance for temperatures below 33 degrees. Confidence continues to
decrease for additional frost/freeze headlines early this week,
though with high pressure drifting overhead and abnormally dry
airmass in place, potential returns toward the end of the week.

Rain chances... CAMs showing light rain across most of the
forecast area this evening into tonight as clipper-like low passes
to the north and WAA increases. As such, rain chances increase
after 00Z within isentropic forcing. QPF should remain minimal
as high pressure puts up a good fight as it so often does in this
scenario. NBM probabilistic guidance shows only a 10 to 30%
chance for exceeding 0.25" of rain north of Hwy 29 through Tuesday
morning. Remain skeptical that quick shot of moisture will be able
to hold out, so will see what happens.

Persistence forecast more or less in place for the remainder of
the week as ridge of high pressure puts us under stagnant
northwest flow regime. Moisture-starved front is progged to
traverse the area Tuesday evening into Wednesday, increasing winds
and bringing temperatures into the low to mid 60s. Still no signal
for any organized systems through the extended, which does not
bode well for northern Wisconsin where D2 (Severe) to D4
(Exceptional) drought conditions exist. Expect fire weather
concerns to increase over the next couple of weeks due to several
rounds of frost/freeze, increasing fine fuels, and afternoon RHs
routinely falling into the low to mid 30s across the sandy soils.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 600 AM CDT Mon Oct 5 2026

Expect mostly clear skies through this afternoon, with some fair
weather cu developing across the north. SCT showers are then
progged to arrive to RHI, AUW, and CWA this evening, progressing
to the east-central sites overnight. Have included PROB30 mention
of SHRA at all terminals for rain arrival. Flying conditions
should remain VFR as rain falls from a mid cloud deck.

Northwest winds will shift to southerly late this afternoon into
this evening, remaining under 10 knots. Southerly winds then
ramp up toward the end of the TAF period, as well as LLWS concerns.

&&

.MARINE...
Issued at 130 AM CDT Mon Oct 5 2026

Gradient winds are set to increase under southerly return flow
Tuesday afternoon as Pacific cold front traverses the region.
Sustained winds are thus progged to increase to 15 to 25 knots
over the water, with near gale force gusts within the realm of
possibility. Current HREF probabilities for 10 meter wind gusts
over 38 mph are 40 to 80%, highest near Death`s Door. As such,
conditions looking pretty slam dunk for Small Craft Advisory
criteria being met, with decent signal for gales if trends hold.
Waves are expected to build to 6 to 9 ft along the nearshore
waters of Lake Michigan during this time, with 2 to 4 ft waves
forecast on the Bay. Have opted to throw out a Gale Watch for all
marine zones, with wind up and wind down Small Crafts for Tuesday
morning and Wednesday morning, respectively.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM CDT this morning for WIZ005-010>013-
018>021-030-073-074.
&&

$$

DISCUSSION.....Goodin
AVIATION.......Goodin
MARINE.........Goodin

NWS GRB Office Area Forecast Discussion