048
FXUS63 KGRB 031045
AFDGRB

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

Forecast discussion for routine morning forecast 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 06Z TAF Issuance
Issued at 1042 PM CDT Thu Apr 2 2026

Poor flying conditions will persist into the overnight hours as a
departing low pressure system leaves ample low-level moisture in
its wake. Widespread IFR/LIFR ceilings will continue across all
terminals at the start of the TAF period. As winds transition to
the west and become gusty, visibilities are expected to improve to
VFR overnight.

A large area of post-frontal MVFR stratus is forecast to linger
through much of Friday morning, with ceilings likely lifting above
1,000 ft AGL between 09z and 15z. Partial clearing toward VFR is
anticipated by Friday afternoon.

The next significant system will rapidly approach after 21z
Friday. Precipitation will initially begin as rain, but cooling
temperatures will likely lead to a transition to freezing rain
after 02z Saturday across north-central WI. Icing conditions are
expected to impact KRHI by the end of the TAF period. Flight
conditions are likely to deteriorate to IFR in the moderate
precipitation Low- level wind shear will also become a concern
Friday night.

Outlook...Significant freezing rain and icing are expected Friday
night into Saturday, particularly across north-central and far
northeast Wisconsin.

&&

.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.......MPC
HYDROLOGY......Kruk

NWS GRB Office Area Forecast Discussion