522
FXUS63 KGRB 180645
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
145 AM CDT Wed Mar 18 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Light snow may taper off to light freezing drizzle this
  morning. Snowfall up to 1 inch is possible, especially across
  central Wisconsin.

- A wintry mix is expected tonight into Thursday. There is a
  30-60% chance for a light glaze or more of ice, especially
  north of Highway 10 and south of Rhinelander and Sturgeon Bay.

- Temperatures rising back above normal by late this week. The
  rising temperatures will lead to snowmelt and increased flows
  and rising levels on rivers and streams. Several rivers may
  reach bankfull or even minor flood stage.

&&

.DISCUSSION...
Issued at 144 AM CDT Wed Mar 18 2026

Clipper system this morning:

An area of light snow will continue moving through the area this
morning, which may taper off to freezing drizzle as mid level
moisture gets stripped out, as a clipper system tracks through the
region. Given most roads are still snow covered from the previous
system, additional impacts are expected to be minimal during the
morning commute.

Clipper system tonight into Thursday:

The next clipper system arrives quick on its heels tonight,
bringing a swath of mixed precipitation to the area. Model
soundings indicate some dry air in the mid levels will cause
freezing rain at times, with warm surface temperatures likely
leading to mainly rain at times south of Highway 10 and deeper
moisture leading to a better chance for snow across the far north.
Any precipitation should end by Thursday morning as the system
moves off to the east.

QPF amounts have increased this run, as well as the probabilities
for icing across the region. Current NBM probabilities for a
glaze of ice have risen to 20-40% along and north of highway 29
with a 10-20% chance south of highway 29 as well as the far north.
The probability for 0.1 inches or greater of ice is around 10% in
a narrow corridor north of highway 10 and south of a line from
Rhinelander to Sturgeon Bay. HREF probabilities are even more
impressive indicating a 40-60% chance for at least a glaze of ice
south of Rhinelander and Sturgeon Bay and north of Highway 10 and
a 10-20% of 0.1 inches of ice or greater in this same area.
Although these probabilities initially appear to warrant a Winter
Weather Advisory, there are still some model differences and some
models are much less robust with QPF amounts. Therefore, will let
the subsequent shift take another look at probabilities and issue
any headlines if needed. The best window for this icy
precipitation appears to be in the 9 pm tonight through 6 am
Thursday window, so the Thursday morning commute will likely be
impacted.

Clipper systems late this week into this weekend:

Another couple clipper systems cross northern Great Lakes
Thursday night into Friday, then again this weekend. Current
indications are that main swath of snow Friday will be farther
north across Upper Michigan, though far northern and far
northeast WI could see up to 1 inch of snow late Thursday night
into Friday morning. Clipper for the weekend could impact more of
our area. but probabilities over the north are very low for even
an inch of snow.

Temperatures/Snowmelt:

Temperatures start rebounding today as highs get into the 30s,
then reach normal to slightly above normal by Thursday with
readings mainly in the 40s away from the immediate Lake Michigan
shoreline. Saturday has the greatest chance of seeing highs over
50 degrees (50-90%), before temperatures cool back to normal or
even slightly below normal Sunday into early next week. Minimum
temperatures will be mostly below freezing, which should allow for
a gradual melting of snowpack.

As temperatures warm later this week into the weekend, the snow
melt will no doubt result in increasing fast flows and rising
river levels. Some rivers could reach bankfull or even minor
flood stage. At this point though with lack of a rapid,
significant warmup and heavy rain, widespread flooding is not
expected. This will have to be monitored as we progress through
the end of the month.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1027 PM CDT Tue Mar 17 2026

A clipper system will bring a round of light snow to the area
overnight. Under an inch is expected across much of the area,
except out towards Wausau, Mosinee, Marshfield and Wisconsin
Rapids where an inch to an inch and a half. VFR VSBY`s and CIGS
will drop into the MVFR and at times into the IFR conditions due
to the light snow overnight into Wednesday morning. As the light
snow diminishes late tonight into Wednesday morning, a little
freezing drizzle is possible. CIGS and VSBYs improve into the VFR
category Wednesday afternoon. The next clipper system will bring
rain and snow, possibly a wintry mix across the north late
Wednesday night.

&&

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

&&

$$

DISCUSSION.....Kurimski
AVIATION.......Eckberg

NWS GRB Office Area Forecast Discussion