045
FXUS63 KGRB 041115
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
615 AM CDT Sun Oct 4 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Areas of frost possible over north-central and far northeast
  Wisconsin late tonight into Monday morning, with patchy frost
  making it into portions of central Wisconsin at times. A Frost
  Advisory has been issued.

- Decreasing frost potential Monday night, though frost chances
  return toward the end of the week.

- Prolonged stretch of dry and seasonable weather expected
  through most of this week.

&&

.DISCUSSION...
Issued at 100 AM CDT Sun Oct 4 2026

Radar currently shows showers hastily departing the forecast area
early this morning as LLJ ejects to the northeast and rain outruns
better forcing along the front. Showers should completely exit by
around 08Z, though remnant moisture under shallow inversion should
keep some low clouds around through most of the morning. Skies
should then clear out this afternoon as winds shift to the
northwest and cooler, more stable air filters in.

Frost/freeze potential... Par for the course, frost potential on
track for late tonight into Monday morning as high sits overhead,
winds decrease, and windows for clearing occur. MOS guidance once
again showing solid signal for temperatures in the low to mid 30s
over portions of north-central to far northeast Wisconsin, with
a couple cold spots along the Upper Peninsula border even
dropping below freezing. Have opted to throw out a Frost Advisory
for areas north of Hwy 29 where confidence is greatest (60 to 90%)
for temperatures below 36 degrees. Similar to previous nights,
possibility exists for an upgrade to Freeze Warning for a county
or two, though forecast lows below freezing were not widespread
enough to do so on this shift. Would also not be surprised to see
some shallow ground fog around early Monday morning due to high
RHs. Frost threat decreasing for Monday night as gradient winds
increase and mid clouds stick around.

Dry pattern ahead... Ridge of high pressure will be the main
driver of the synoptic pattern through the extended, with
ensembles continuing to move the mid-week cold front through our
area mostly dry. Beyond that, not seeing any strong signals for
organized systems through at least the middle of the month. With
frost/freeze headlines already in play, this may result in
increasing fire weather concerns over the next several weeks due
to current drought status and increasing fine fuels.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 615 AM CDT Sun Oct 4 2026

MVFR cigs will likely stick around for the first few hours of the
TAF period due to lingering low-level moisture, though skies
should clear out quickly after 18Z. FEW to SCT fair weather cu may
develop this afternoon, mainly across the north. VFR flying
conditions are then expected through Monday morning, with mid
clouds passing overhead at times.

Winds will be sustained out of the northwest throughout the
forecast period. Gusts between 15 and 20 knots will be possible
at all terminals this afternoon, with winds becoming light and
variable tonight.

&&

.MARINE...
Issued at 100 AM CDT Sun Oct 4 2026

Winds and waves remain elevated on the Bay and Lake early this
morning, with winds gusting to 25 mph and waves 4 to 5 ft. Waves
should continue to build to 4 to 7 ft (highest near Death`s Door)
through around 12Z. Winds then subside and shift to the northwest
after 15Z, during which marine hazards will come to an end.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 2 AM to 8 AM CDT Monday for WIZ005-010>013-
018>021-030-073-074.
&&

$$

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

NWS GRB Office Area Forecast Discussion