573
FXUS63 KGRB 041129
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
629 AM CDT Fri Apr 4 2025

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Flows will remain elevated on area rivers and streams into next
  week due to recent rainfall. Minor flooding is possible at a
  few locations.

- There is a chance for snow showers (30-40 percent) Sunday night
  into Monday as strong cold front arrives.

&&

.DISCUSSION...
Issued at 256 AM CDT Fri Apr 4 2025

Short Term...Today...Tonight...and Saturday

High pressure across the Great Lakes will lift northeast towards
Quebec today, allowing low pressure systems to approach the region
from the south and west. Although dry weather is expected today,
the squeeze of the aforementioned low pressure systems will cause
an increase in clouds throughout the day, with cloudy skies
expected by this afternoon. Highs today are expected to mainly be
in the upper 40s to lower 50s.

The two low pressure systems will mainly be glancing blows to
Wisconsin as the low to the south tracks towards the southern
Great Lakes while the low to the west lifts northeast towards
James Bay. Despite the glancing blows, these systems could bring
some light precipitation to the region tonight into early Saturday
morning as the system to the west pushes a cold front through the
region with modest mid level frontogenesis. The areas with the
best chances for precipitation will be east-central Wisconsin
close to the system to the south and far north- central Wisconsin,
which will be close to the system to the west. Central and
northeast Wisconsin will be in the in-between zones of these
systems with a small (10-20 percent) chance of seeing
precipitation hitting the ground. Precipitation is expected to
mainly be rain across east-central Wisconsin and the lakeshore
given the warmer boundary layer with rain starting in north-
central mixing with and changing over to all snow as the night
progresses and cooler air advects into that region. Snowfall
accumulations across the far north will be light, with a tenth or
two possible if anything does accumulate. Lows tonight are
expected to range from the upper 20s across the north, to the
middle 30s across central, east-central Wisconsin and the
lakeshore.

Saturday is expected to be dry as these systems track off to the
east and high pressure establishes itself across the midwest.
Highs on Saturday will be cooler; ranging from around 40 across
the north to around 50 in the Fox Valley.

Long Term...Saturday Night Through Thursday

Primary focus of the extended forecast is a chance (30-40%) for
accumulating snow late Sunday night into Monday morning as upper-
level jet energy and a cold front swing over the region. Areas east
of I-39 have the greatest chance (30-50%) of seeing at least one
inch of snow by Monday morning. This may cause a few minor impacts
during the morning commute, particularly for areas near Lake
Michigan where probs for greater than 1" are highest. Cooler air
streaming into the region behind the front may kick off some light
lake effect snow across far northern WI which may linger through
much of the day Monday. The middle of next week looks mostly dry as
a ridge of high pressure is forecast to develop over the upper-
Midwest. Next chance for light precipitation does not look to come
until the end of the week.

Seasonally cool temperatures are expected Monday with highs in the
upper 20s to upper 30s. The rest of the week temperatures should be
near normal for early April.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 629 AM CDT Fri Apr 4 2025

VFR conditions are expected today as high and mid clouds slowly
lower throughout the day. Low pressure systems passing to the
south and west will cause clouds to thicken and lower further
tonight, with conditions falling to MVFR. Light rain will arrive
late this evening across east-central Wisconsin with the best
chance (50-60 percent) at KMTW and a lower chance (30 percent)
across the Fox Valley (KGRB and KATW). Further north, a mix of
rain and snow is possible (30 percent) as a cold front approaches
from the west.

&&

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

&&

$$

DISCUSSION.....Kurimski/GK
AVIATION.......Kurimski