NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 041219
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
719 AM CDT Sat Apr 4 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Freezing rain and rain are expected through late this morning.
  Additional significant icing is expected across northern and
  portions of central Wisconsin.

- Flooding concerns continue through early next week due to recent
  rainfall and the additional rainfall expected today.

- A chance of rain and snow is possible Sunday into Monday, with
  additional periods of precipitation from Tuesday night through
  next weekend.

&&

.DISCUSSION...
Issued at 512 AM CDT Sat Apr 4 2026

Ice Storm This Morning:

A mix of freezing rain and rain were observed early this morning
via radar and surface observations. While the bulk of the
precipitation was gradually exiting the forecast area to the
east/northeast, radar and surface observations upstream were
indicating drizzle and freezing drizzle were occurring with another
round of lighter precipitation trailing behind that, which was just
entering western WI. These conditions are expected to move over
the forecast area throughout the morning and exit late this
morning, adding to the rainfall and ice accumulations over the
area. The additional ice amounts (0.05-0.15 inches) will be
focused across northern WI until surface temperatures warm above
freezing from south to north, causing a transition to rain
towards the late morning.

No changes made to the Ice Storm Warnings or Winter Weather
Advisories that remain in effect through mid-morning. While
ice accumulations are still expected across northern WI through
mid-morning, observations in far northern WI overnight indicated
the precip was falling as snow for a period before switching to
freezing rain, which could lower total ice accumulations.
Generally, still anticipating totals of at least 0.25 inches of
ice across northern WI.

Ice will mainly accumulate on elevated surfaces, which is
supported by normal traffic speeds and WI DOT roads conditions of
partially covered roads this morning. The ice accumulating on
elevated surfaces and easterly winds gusting to 30 mph this
morning will lead to power outages and tree damage being the main
impacts, which this morning's power outages across WI support
(mainly in central and northern WI).

Remainder of Today/Tonight:

A lull in precipitation is expected this afternoon as the low
pressure system becomes nearly vertically stacked over northern
WI. As the low begins to exit the region this evening, winds will
switch to the northwest and usher in colder air. This will
generate light snow showers across far northern WI through the
overnight hours. Some sprinkles or flurries may also move over
central and east-central WI during the evening as well. By late
tonight, snow accumulations of a dusting to a couple tenths are
possible across far northern WI. West to northwest winds will also
gust to 20 to 30 mph this evening into tonight.

Rest of the Forecast:

Dry weather is expected for most of Sunday before a clipper system
brings a chance of rain and snow from Sunday evening through
Monday. Moisture appears to be limited with this system, so
impacts will be low. An active pattern looks to set up from mid
next week through next weekend with several chances for
precipitation, but details, such as timing and p-type, remain
uncertain at this time.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 719 AM CDT Sat Apr 4 2026

The ongoing system will keep a low stratus over the area through
most of the day with a mix of IFR and LIFR conditions expected
across all TAF sites. Lingering freezing rain or freezing drizzle
will continue at AUW/CWA through 14z Sat, and at RHI through 16z
Sat before transitioning to rain or drizzle. The precip will end
at AUW/CWA around 17z Sat, and at RHI around 19z Sat. Rain showers
or drizzle will be moving over the east-central WI TAF sites at
times through roughly 16z Sat.

A brief lull in precipitation is expected this afternoon before
light rain/snow mix moves into the area from the west late this
afternoon/evening. Snow and IFR conditions are expected to remain
longest at RHI through late this evening before improving to MVFR.
Elsewhere, cigs will improve to MVFR from east to west late this
afternoon through late this evening.

East winds this morning will shift west around midday today and
continue through the end of this TAF period. Gust to 20 to 25
knots will occur at times.

&&

.HYDROLOGY...
Issued at 512 AM CDT Sat Apr 4 2026

The combination of Thursday's and today's rainfall will lead to
flooding concerns. Thursday's rainfall was greatest across most of
the area, except in north-central WI. By the end of today, the
greatest rainfall amounts will be across the same areas. That
being said, these areas will be more susceptible to flooding in
low-lying and poor drainage areas. Additionally, some rivers have
already been responding to the combined rainfall: the Oconto
River and Wolf River at Shiocton are in minor flood stage, with
several others at bankfull. A few river sites are also forecast to
approach/reach minor flood stage through early next week.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Ice Storm Warning until 10 AM CDT this morning for WIZ005-
010>013-018-019.
&&

$$

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