452
FXUS63 KGRB 141717
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1217 PM CDT Mon Sep 14 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- Chilly temperatures in the mid 30s will cause widespread frost
  across northern WI early morning.

- A round or two of heavy rain and storms is expected this
  afternoon through Tuesday. Rainfall amounts of 1 to 3 inches are
  possible across central and east-central WI. The severe weather
  threat is low.

- Hazardous conditions for small craft return this afternoon and
  continue into Tuesday. Small Craft Advisories or a Gale Warnings
  are in effect this afternoon and tonight. A Small Craft Advisory
  is in effect Tuesday morning, ending during the late afternoon.

- High waves will lead to an increased risk of rip currents at
  Lake Michigan beaches this afternoon into Tuesday afternoon
  where a Beach Hazardous Statement is in effect.

&&

.DISCUSSION...
Issued at 158 AM CDT Mon Sep 14 2026

Forecast for a a round or two of heavy rain this afternoon
through Tuesday morning remains on track. A strong low pressure
system is evident on WV imagery over the northern Rockies early
this morning. This system will progress east into the northern
Plains today with strengthening southerly flow ahead of the low
drawing seasonally high moisture into the region. Expect rain to
initially push into central WI during the early afternoon,
however, the exact timing for the onset of precipitation remains
somewhat uncertain as forecast soundings do show dry air in the
low-levels that will need to be overcome. This initial round will
likely be light to moderate widespread rain that spreads across
the area by afternoon. A second round of rain is then expected
beginning this evenings over central WI as a strong LLJ pushes
noises into the region. This second round is expected to bring a
more focused area of moderate to heavy rain to central and east-
central WI late this evening and overnight. Between these two
rounds of rain HREF LPMM 24hr rainfall totals show a corridor of
2-3" totals south of a line from Wausau to Sturgeon Bay with 0.5
to 1" north of that line. The exact placement of this higher end
corridor may still shift north or south slightly. A few embedded
thunderstorms are possible with this system, but weak instability
keeps the severe threat low. Rain will come to an end from west
to east Tuesday morning high pressure them bringing dry conditions
for the remains of Tuesday and much of Wednesday.

For the remainder of the week a baroclinic zone is expected set up
over or just south of the forecast area. This will keep a 40-70%
chance for showers and occasional thunderstorms Wednesday afternoon
through next weekend, however, it will likely not rain that entire
period. Temperatures will hover near to slightly below normal next
week depending on where the boundary sets up each day.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1204 PM CDT Mon Sep 14 2026

Tranquil early this afternoon with rain and a few thunderstorms
moving northeast into the region during the mid to late afternoon
hours and early this evening over far northeast WI. Rain and a few
thunderstorms will continue into early Tuesday morning, gradually
ending from northwest to southeast overnight into early Wednesday
morning. VFR CIGS will fall into the IFR/MVFR category later this
evening and overnight. CIGS should rapidly improve Wednesday
morning.

As for winds, south to southeast winds will continue to increase
this afternoon. Low level wind shear will develop during the late
afternoon or early this evening from 180-190 degrees at 40-50 kts
which will veer to the southeast tonight. Surface winds will
remain up tonight, with some guidance indicating gusts close to
30 knots this evening across eastern WI. The cold front will push
across the area late tonight into Tuesday morning, with gusty
west winds behind it that will linger into Tuesday afternoon.

&&

.MARINE...
Issued at 158 AM CDT Mon Sep 14 2026

Strengthening southerly winds today will lead to hazardous boating
conditions on Lake Michigan and Green Bay. Strongest winds, with
gale force gusts are expected late this afternoon through Tuesday
morning. During the period waves on Lake Michigan may reach 12+ ft.
While winds won`t be as strong Tuesday afternoon gusts of 20-25kts
will continue to create conditions hazardous to small craft. With
the high waves strong rip currents are also expected to create
dangerous swimming conditions at Lake Michigan beaches.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from 7 PM CDT this evening through
Tuesday evening for WIZ022.

Beach Hazards Statement from 4 PM CDT this afternoon through
Tuesday afternoon for WIZ040-050.
&&

$$

DISCUSSION.....GK
AVIATION.......Eckberg
MARINE.........GK