291
FXUS63 KGRB 150406
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1106 PM CDT Mon Sep 14 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- A round or two of heavy rain and scattered storms is expected
  this afternoon and tonight. Rainfall amounts of 1 to 2 inches
  are possible across central into northeast WI, with locally
  higher amounts possible. The severe weather threat is low.

- Hazardous conditions for small craft return late this afternoon
  and continue into Tuesday afternoon. Small Craft Advisories and
  Gale Warnings are in effect for various times through Tuesday
  afternoon.

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

- Dry conditions expected Tuesday afternoon through Wednesday,
  then there are periodic chances of showers and storms Wednesday
  night into the weekend.

&&

.DISCUSSION...
Issued at 205 PM CDT Mon Sep 14 2026

A chilly start to the day as temperatures dropped into the lower
to middle 30s across the north. The cold spot was at the Eagle
River COOP site at 31 degrees. Temperatures rebounded quickly as
temperatures early this afternoon climbed into the 60s, with a few
lower 70s across east-central WI. Clouds were on the increase
while rain was entering western WI as of 1 PM.

For tonight, a cold front will approach from the west. The 850mb
low level jet will increase to 50-60 knots, resulting in 850mb
warm advection and will result in the precipitation expanding and
moving northeastward into the area later this afternoon and
continuing this evening. Two rounds of heavy rain expected with
the first round across northern WI, generally north of Highway 29
late this afternoon and early this evening. The second round of
heavy rain is expected across central into east-central WI during
the late evening and overnight hours. Most unstable CAPE values
not impressive with less than 400 J/KG, thus thunderstorm activity
should be isolated to scattered across central and east-central.
The risk of severe weather is low. Despite strong winds aloft,
stable layer aloft should prevent much of the winds from mixing
down to the surface. Latest model guidance suggest a band of
heavier rainfall extending from central WI northeast towards
Marinette County where totals of 1 to 2 inches are expected. Could
not rule out some locally higher amounts. The showers and storms
should exit the area from northwest to southeast overnight into
early Tuesday morning. Dry conditions should prevail through
Wednesday afternoon.

The baroclinic zone is expected to set up over or just south
of the forecast area, bringing periodic chances of showers and
storms Wednesday night into next weekend. The system for
Friday into Saturday has the potential to bring heavy rain
to the area. Temperatures at or above normal expected
through next weekend.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1105 PM CDT Mon Sep 14 2026

Rain and scattered thunderstorms, some containing heavy rain,
will gradually end from northwest to southeast overnight into
early Tuesday morning. VFR CIGS will steadily fall into the
IFR/MVFR category from west to east through the overnight. Some
fog may form late north-central, including at RHI. Conditions will
gradually improve to VFR by Tuesday afternoon.

Concerning winds, south to southeast winds with gusts 20-30 kts
are expected at times through the night as winds veer southwest.
Low-level jet up to 50 kts will be present most of the night,
leading to LLWS at all TAF sites. The cold front will push across
the area late tonight into Tuesday morning, with gusty west winds
lingering behind it into Tuesday afternoon. Winds will become
light on Tuesday evening.

&&

.MARINE...
Issued at 205 PM CDT Mon Sep 14 2026

Strong southerly winds will bring hazardous conditions to
the bay and Lake Michigan late this afternoon through Tuesday
afternoon. Small Craft Advisories and Gale Warnings are in
effect for various times through Tuesday afternoon. Gale
force gusts to 40 knots are possible later this evening into
the overnight hours while waves on the bay will reach 3-6 ft
and 6-12 ft on Lake Michigan. With the high waves comes to
the increased risk of rip currents at Lake Michigan beaches
where a Beach Hazards Statement is in effect.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement through Tuesday evening for WIZ022.

Beach Hazards Statement through Tuesday afternoon for WIZ040-050.
&&

$$

DISCUSSION.....Eckberg
AVIATION.......JLA
MARINE.........Eckberg

NWS GRB Office Area Forecast Discussion