NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 051157
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
657 AM CDT Sun Apr 5 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Isolated snow showers/flurries this morning with scattered rain
  and snow showers tonight. Additional scattered snow showers and
  gusty north/northwest winds return Monday afternoon.

- Next chance of precipitation Tuesday night through Thursday.

- Flooding concerns continue this week due to recent rainfall as
  some rivers reach bankfull or minor flood stage.

&&

.DISCUSSION...
Issued at 357 AM CDT Sun Apr 5 2026

This Morning through Monday...Lingering low-level moisture on the
backside of a departing low pressure system was producing
scattered light snow showers or flurries over the area early this
morning. Lake-effect snow showers were also being reported in far
north-central WI early this morning. Additionally, low-level
winds of 25-35 kts were occasionally mixing to the surface where
the snow showers/flurries occur, producing surface gusts of 30 to
nearly 40 mph. These conditions will improve around sunrise today as
the low tracks further from the area; but, will linger for a few
hours longer into the morning in far north-central WI.

Sunshine returns today before clouds increase again towards this
evening as WAA increases ahead of an approaching embedded mid-
level shortwave and weak surface low. As a result, scattered rain
and snow showers will move over the area, mainly during the
evening hours for most, but continuing across far northern WI
through at least Monday morning.

By midday Monday, a frontal boundary looks to drop south over the
area. Paired with steep low-level lapse rates and some surface
instability, CAMs indicate diurnally driven snow showers
developing over the area. Given the favorable low-level
parameters, some of these snow showers may produce brief bursts of
snow, causing reductions in visibility at times through the early
evening. Forecast soundings also show an inverted-V with low-
level winds of 25-35 kts, which would also produce gusty surface
winds during this time. While confidence is low for true snow
squalls occurring due to a not-so-well defined frontal boundary,
will continue to monitor this potential. Any of the snow showers
will come to an end a few hours after sunset with the loss of
daytime heating and as high pressure moves into the area. Between
tonight and Monday evening, probabilities for snow accumulations
of 1 inch or more remain focused across far northern WI (30-50%),
but a dusting to a couple tenths of an inch are possible
elsewhere.

Rest of the forecast...Low-level southwest flow ahead of a low
pressure system/cold front looks to generate some WAA driven
precip over the area Tuesday night into Wednesday. Models are not
in agreement with thermal profiles and surface temperatures at
the onset of this precip, indicating a possible mix of
rain/snow/freezing until surface temperatures warm above freezing.
This will be follows by pre-frontal rain occurring sometime
between Wednesday afternoon and Thursday, as there are still some
timing disagreements. Models are in agreement with dry conditions
on Friday with high pressure overhead, but quickly fall out of
line for the weekend.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 657 AM CDT Sun Apr 5 2026

MVFR cigs and low-end VFR cigs (cloud bases between 1500 to 4000
ft AGL) prevailed across the region this morning. The back edge of
the clouds was beginning to move into the region with the MVFR
cigs ending from west to east between 12z and 16z. Gusty northwest
winds of 15 to 25 kts was observed with these clouds, but will
gradually subside throughout the day.

Clouds and MVFR cigs are expected to move back into the region
from west to east late this afternoon into this evening and
continue through the end of this TAF period. Scattered to
isolated rain and snow showers will move over the region with
these lower clouds. However, since these showers will be scattered
to isolated in coverage, did not feel confident enough to include
in the TAFs other than using PROB30 groups. Some of the showers
may also produce MVFR vsbys at times.

&&

.HYDROLOGY...
Issued at 357 AM CDT Sun Apr 5 2026

Many area rivers remain at/near bankfull or in minor flood stage
this morning due to runoff from recent rounds of rainfall and
melting snow/sleet. The rivers across central and eastern WI will
continue to see the highest levels into Monday, with the Yellow,
Wolf, Embarrass, Oconto, Peshtigo, and Kewaunee rivers seeing the
brunt of the flooding. The other rivers across east-central WI
will likely remain near flood/bankfull stage today as well.
Although additional significant precipitation is not forecast
through Wednesday, many of these rivers will remain at or slowly
rise to bankfull or minor flood stage. No rivers are forecast to
reach moderate flood stage. Across north-central WI, less rainfall
fell, plus some snow is still on the ground, so runoff was
reduced and no flooding is expected.

&&

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

&&

$$

DISCUSSION.....Kruk
AVIATION.......Kruk
HYDROLOGY......Bersch