FXUS63 KGRB 150533
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1233 AM CDT Thu Oct 15 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Widespread rain arrives Thursday afternoon, and will continue at
  times through Friday. Expect most areas to see between 0.5 and
  1" of total rainfall.

- Northwest winds increase on Friday, with gusts between 35 and 45  
  mph possible. Gale force gusts expected across marine zones.

- A widespread frost/freeze event is expected Friday night into early
  Saturday morning.

- A warming trend and breezy southwest winds will bring daytime high
  temperatures back into the 60s late this weekend, with minimal 
  rain chances through mid-week.

&&

.DISCUSSION...
Issued at 1000 PM CDT Wed Oct 14 2026

Rain chances Thursday/Friday... Biggest change from previous
forecast cycles centers around a noticeable jump in QPF amounts
Thursday through Friday as models hone in on timing/evolution of 
the upper pattern. Signs still point toward phasing of northern 
and southern stream lows over the western Great Lakes Thursday 
night as a deepening surface low ejects from the central Plains.
Jet energy ramps up during this time as moisture plume (near 99th
percentile PWATs) interacts with mid-level FGEN in proximity to
low pressure over southern Wisconsin. As such, probabilities for
receiving one inch of QPF now stand at a widespread 30 to 60%.
Thus expecting a soaking rainfall across most of northeast
Wisconsin, which will be beneficial to areas across the north 
that have been in an extended period of drought. Stratiform rain 
then becomes more scattered in coverage on Friday, though wrap 
around moisture should keep at least light rain around for most of
the day.

Temperatures... Following a decent stretch of seasonable
weather, cold FROPA and intrusion of arctic high will bring a 
brief spell of well below normal temperatures from the Plains to 
the Midwest on Friday. 850 mb temperatures plunge to around 2 to
5C below zero, which will translate to high temperatures
reading in the mid 40s across the north to the mid 50s in the Fox
Valley. Overnight lows will then fall into the mid 20s to low 30s
inland of Lake Michigan, pointing toward a high confidence setup 
for frost/freeze under clearing skies and light winds. If trends
hold, expect most areas to see a hard freeze that would 
effectively put an end to the growing season. Expect headlines to
be forthcoming in the next day or so. Return flow then quickly
sets up over the weekend, resulting in high temperatures 
rebounding into the 60s.

Extended... High pressure looks to be the main driver of the
synoptic pattern through at least the middle of next week, with 
no organized systems on the horizon. More active pattern looks to
set up beyond then as upper flow re-amplifies, though details are
few this far out.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1229 AM CDT Thu Oct 15 2026

CIGS varied between 2,500 and 4,000 feet early this morning. 
CIGS will drop today into the IFR category as rain arrives by 
late morning or afternoon. Rain will continue tonight into Friday
morning before coming to an end. CIGS should improve on Friday.
The big story will be the strong northwest/north winds on Friday,
with gusts between 30 and 35 knots expected across the region, 
with a few gusts to 40 knots across Door County and east-central 
WI. Winds will subside Friday evening. 

&&

.MARINE...
Issued at 1000 PM CDT Wed Oct 14 2026

Gradient winds on the back edge of the departing surface low ramp
up Thursday night into Friday morning, putting us solidly within 
northwest flow and CAA regime. Deep daytime mixing will tap into
45 to 50 knot winds at 850 mb Friday afternoon, which will
result in a brief window for gale force gusts over all marine 
zones through Friday evening. NBM probabilistic guidance continues
to show a healthy signal (60 to 90%) for gusts exceeding 38 mph, 
highest along the Lake Michigan nearshore waters south of 
Kewaunee. Waves build 6 to 9 ft on the Lake and 3 to 6 ft on the 
Bay during this time, subsiding Friday night as winds shift to 
more westerly and the pressure gradient eases up. Gale Watches
remain in effect.

&&

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

&&

$$

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