NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 031203
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
703 AM CDT Fri Apr 3 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Freezing rain and heavy rainfall are expected this evening
  through Saturday morning. Significant icing is expected across
  northern WI and portions of central WI. Tree damage and power
  outages are expected where icing amounts are greatest, with some
  slippery or ice-covered roads. Ice Storm Warnings and Winter
  Weather Advisories have been issued.

- Flooding concerns continue this weekend into early next week due
  to the recent rainfall from Thursday and the additional rainfall
  expected this evening through Saturday.

&&

.DISCUSSION...
Issued at 545 AM CDT Fri Apr 3 2026

Ice Storm This Evening through Saturday Morning...Quiet, but
cloudy, conditions are expected for much of today ahead of an
approaching Colorado Low. As this system approaches the area,
strong isentropic lift, f-gen, and WAA will work in tandem to
generate the next round of rain and freezing rain from late this
afternoon through Saturday morning. While the precip will start as
rain across the southern half of the forecast area, northern WI
will see a mix of rain and freezing rain. Throughout the evening,
freezing rain will become the dominant p-type across the north. As
the colder air sags south into central WI late this evening, the
rain will transition to freezing rain. By early Saturday morning,
temps will start rising from south to north, leading to a
transition back to rain, reaching the north by mid- morning
Saturday. Throughout this entire time, east-central WI to the
lakeshore areas will see rain. A few elevated, non-severe
thunderstorms are also possible across the area this evening and
tonight.

Similar to Thursday's system, this system will produce
significant ice accumulations, but mainly across northern WI.
Ice amounts across northern WI will range from 0.25 to 0.50
inches, with the potential for locally higher amounts. The further
south you go across central WI, ice amounts decrease with amounts
of 0.10 to 0.25 inches. Given the signal for 0.25 inches or more
of ice has continuously increased, felt confident to issue an Ice
Storm Warning for northern WI. Included Menominee, Marathon,
Shawano, northern Oconto, and southern Marinette counties in the
Ice Storm Warning as well; however, the higher ice amounts will be
focused more in portions of each county versus county-wide like
across the north. Decided to also issue a Winter Weather Advisory
for Wood, Portage, Waupaca, and southern Oconto counties due to a
combination of ongoing power outages from Thursday's system and
the additional ice accumulations up to 0.10 inch from tonight's
system.

Saturday into Saturday night...As the Colorado Low tracks
overhead Saturday afternoon, there will be a lull in the precip
for most. However, forecast soundings suggest locations across
northern WI could see a period of drizzle or freezing drizzle.
Trailing this will be the system's cold front, allowing for
potential snow showers Saturday evening/night area-wide, but
mainly focused across north-central WI. Minor snow accumulations
of a couple tenths of an inch are possible across north-central
WI.

Following this system, upper-level northwest flow will allow a
clipper-like system to move over the area sometime between late
Sunday and Monday. Snow looks to be the main p-type, but impacts
appear minor at this time.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 703 AM CDT Fri Apr 3 2026

A mix of IFR and MVFR cigs prevailed across the region this
morning due to a low stratus deck. However, satellite shows
partial clearing over far northeast WI, which may sneak into the
east-central WI TAF sites. Otherwise, MVFR cigs are expected
throughout the day before the arrival of the next system. Rain is
expected to expand from west/southwest to east/northeast after 22z
Fri. The rain is expected to transition to freezing rain from
north to south after 00z Sat, but is not expected to reach the
east-central WI TAF sites. Flying conditions will deteriorate with
IFR cigs and MVFR vsbys across all TAF sites throughout the
evening, and perhaps to LIFR cigs at RHI. The freezing rain and
rain will continue through the end of this TAF period.

There is also some potential for thunderstorms this afternoon and
evening, but did not feel confident enough to include in this TAF
issuance.

West/northwest winds up to 10-15 kts will veer north this
afternoon. Winds will then veer northeast to east and increase
this evening/night with gusts to 20 to 25 kts.

&&

.HYDROLOGY...
Issued at 545 AM CDT Fri Apr 3 2026

The combination of Thursday's rainfall and the progged system for
this evening-Saturday will lead to flooding concerns. Thursday's
rainfall was greatest across most of the area, except in north-
central WI. For this evening-Saturday system, a widespread 0.75-1
inch of QPF is forecast. That being said, areas that received
heavy rainfall from Thursday will be more susceptible to flooding
in low-lying and poor drainage areas. Additionally, some rivers
have already been responding to Thursday's rainfall: Oconto River
in minor flood stage, several others at bankfull. A few river
sites are also forecast to approach/reach minor flood stage this
weekend or early next week: Yellow River, Oconto River (already
in minor flood stage), Wolf River, and Embarrass River.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Ice Storm Warning from 7 PM this evening to 10 AM CDT Saturday
for WIZ005-010>013-018-019.

Ice Storm Warning from 9 PM this evening to 7 AM CDT Saturday
for WIZ020-021-030-031-073.

Winter Weather Advisory from 9 PM this evening to 7 AM CDT
Saturday for WIZ035>037-074.
&&

$$

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