733
FXUS63 KGRB 182325
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
625 PM CDT Sun Oct 18 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Conditions will be hazardous to small craft through late tonight
  due to persistent southerly winds producing high waves.

- Dry and warm conditions this week. Next smaller chances for rain
  (20-40%) not until next weekend.

- Late night, early morning fog possible this week.

&&

.DISCUSSION...
Issued at 111 PM CDT Sun Oct 18 2026

Through Monday...Windy this afternoon with gusts to 35 mph at
times. Diminishing pressure gradient and weakening low-level jet
tonight will allow for lighter winds late tonight into Monday. As
winds become light, could be a touch of fog late tonight central
to north-central WI. Temperatures this afternoon and Monday
afternoon will reach the lower 60s. Average highs for mid October
are in the mid to upper 50s.

Dry and warm this week, with small chances for rain next weekend...
Rising mid-level heights with prevailing high pressure at surface
add up to mainly dry conditions this week. Still a very small
(10-20%) chance of showers showing up on LREF late Wednesday into
Wednesday night, but main lift/moisture remains north of Lake
Superior. NBM pops remain less than 10%. Approaching front with
main sfc low over central Canada is showing up as low chances
(20-40%) for showers Saturday night into Sunday. Moisture is
lacking with the front though, so this does not look to produce
much rain if it even occurs. This shows up when looking at
probabilities of seeing over 0.10 inch, which are less than 10%.
Temperatures in the lower 60s early this week will warm steadily
into the upper 60s to even lower 70s by late this week into next
weekend depending on cloud cover, rain chances.

Late night, morning fog this week...High pressure drifting across
and nighttime cooling, light winds results in setup for at least
patchy ground fog especially Monday night through Wednesday night.
A couple of these nights could have locally dense fog.

Looking at the longer range, there is no signal at this point of
any significant pattern change per the ECMWF into early November
and the time lagged CFS data into mid November. This lines up with
latest 3-4 week outlook from CPC. Thus, warmer and dry weather will
be the theme until further notice. With that, we`ll have to keep eye
on fire weather concerns, especially on windier days.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 621 PM CDT Sun Oct 18 2026

VFR conditions are expected for this TAF period with high clouds
at times, especially on Monday. Patchy ground fog is possible
a few hours before sunrise on Monday morning, but confidence is
not high enough to include in this TAF issuance. If it develops,
AUW/CWA/RHI would be most favored.

As winds decouple at the start of this TAF period, the gusty
southwest winds will end; however, LLWS will prevail as southwest
winds of 35-40 kts remain just above the surface ending around
06z-08z Mon. Winds will be light and variable into Monday morning,
with a slight easterly component during the afternoon.

&&

.MARINE...
Issued at 111 PM CDT Sun Oct 18 2026

Small Craft Advisories remain in effect through Sunday evening,
except for the Lake Michigan nearshore north of Sturgeon Bay,
where a Gale Warning is still in effect. Southwest winds gusting
to 30-35 kts, strongest toward open waters of northern Lake
Michigan will produce waves up to 6 to 9 feet on Lake Michigan,
and from 3 to 6 feet on the bay. The peak of the gales will occur
through late this afternoon. A few gale force gusts are also possible
on the central Bay near Deaths Door. Conditions will drop below
Small Craft Advisory criteria late tonight.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......Kruk
MARINE.........JLA

NWS GRB Office Area Forecast Discussion