485
FXUS63 KGRB 061930
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
130 PM CST Tue Jan 6 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Winter Weather Advisories are in effect through late afternoon
  or early this evening for lingering impacts from freezing rain.
  Untreated and secondary roads will remain slippery.

- Dense freezing fog possible late tonight into Wednesday morning,
  especially central and north-central WI. Slippery travel could
  result.

- Rain and some snow expected late Thursday into Thursday night.
  Chances for at least 1 inch of snow highest over northern WI
  (30-40%).

- Another system expected Saturday and Saturday night. Chances for
  at least 2 inches of snow across the entire area range from
  40-60%.

&&

.DISCUSSION...
Issued at 125 PM CST Tue Jan 6 2026

Impacts from freezing rain main issue through this evening. Fog
could become dense again tonight as well. Couple of more systems
bring rain/snow to the region starting late Thursday and lasting
into Saturday night.

Freezing rain and Icing Impacts Through This Evening...
Area of rain and freezing rain continues to slide across the
region. Back edge of steadier precip is into central WI, with very
light mist, freezing drizzle over far northern WI. Rest of the
area will be impacted by rain and freezing rain through late this
afternoon. Temps have slowly warmed over southern portion of the
area, especially along and south of Highway 10. Readings are right
around freezing along the Highway 29 corridor, though Fox Valley
is mainly above freezing now. Area that is probably of most
concern for additional icing of up to 0.10 inch will be northwest
of the Fox Valley into the bayshore areas near Green Bay north to
Peshtigo and Oconto, and possibly over Door County. As the cold
front works southeast this evening, may still see the precip end
as a wintry mix of rain, sleet and snow. This would especially be
true over far northeast WI and across Door County. Earlier
extensions to the Winter Weather Advisory seem fine, though some
adjustments will likely still be needed based on temperatures and
precipitation trends.

Fog Potential Late Tonight into Wednesday Morning...
Late evening into the overnight, once precipitation ends and mid-
level moisture decreases, could see fog form again. This morning
it was dense over the Fox Valley. Late tonight into Wednesday
morning, dense fog may occur over central and north- central WI.
At least that is where the signal from the short term guidance is
most favorable. If and where it does occur, temps will be well
below freezing, so more freezing fog, slippery travel could occur.
Will mention this in the HWO.

A Quiet Interlude In The Active Pattern...
High pressure and gradual mixing will result in skies turning
partly cloudy later Wednesday, with dry weather lasting into at
least midday Thursday. Temperatures will rise into mid 30s on
Wednesday and push into the upper 30s, if not even a spot 40
degree reading on Thursday. Slippery spots may occur on Wednesday
night as temps drop below freezing.

Low Pressure Systems Bring More Active Weather Late This Week into
the Weekend...
Southern stream becomes active with two separate systems poised
to impact the western Great Lakes region. First shortwave and low
pressure system that comes ashore in northern Baja California on
Wednesday arrives over WI on Thursday. Despite look of well
developed deformation axis of QPF on the cold side of the low,
thermals are pretty warm and the main risk of seeing snow will be
over northern WI (north of Wausau to Marinette) on Thursday night.
Probabilities of seeing 1" or more of snow for those areas have
increased slightly, but are still are modest at around 30%.
Otherwise, this looks like mainly a rain event with totals over
0.5 inch looking likely over the southeast area and even some low-
end risk (30-40%) of seeing over 1" of rain, southern Fox Valley
to the lakeshore. Given the melting snow and if this much rainfall
occurs, could have some minor flooding issues where street drains
could be clogged with ice and snow and also in other low-lying
areas.

Second system comes in for the weekend and involves phasing between
the northern stream and southern stream, which is always tricky
to pin down. Also, there is colder air with this system, so the
chances for snow expand to all areas. Spread is high between the
25th and 75th percentile for snow for essentially the Saturday to
Saturday night period. Probabilities for plowable snow over most
of the area (2+") have ticked upward, with 40-60% shown over the
region, lowest north-central, highest eastern and northeast WI.
These recent trends are just emerging, so we`ll need to stay tuned
to see how things continue to trend the next couple days for this
system on Saturday/Saturday night. Does turn colder behind the
system to close the weekend. Could see later forecasts adding some
lake effect to far northern WI.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1146 AM CST Tue Jan 6 2026

Dense fog over the Fox Valley is expected to improve early this
afternoon as freezing rain and rain (with reductions to vsby)
makes its way eastward through the afternoon. The precipitation
will end mid to late afternoon over central and north-central WI
and early this evening over eastern WI. A bit of sleet or snow
may mix with the precip as it ends. Since the freezing line runs
across the Fox Valley and is slowly lifting northward, expect the
precipitation to gradually switch to mainly rain at GRB/ATW by
late afternoon. Cigs will mainly be LIFR-IFR, though pockets of
MVFR could occur through late this afternoon.

Once the precipitation ends this evening, expect fog to develop
over much of the region. Cigs will be LIFR-IFR and vsby could drop
to less than 1/2SM at CWA/AUW and RHI, while being mainly MVFR
elsewhere.

On Wednesday, after low clouds and fog, expect gradual improvement
to MVFR and eventually VFR.

Winds will be light through the TAF period.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 3 PM CST this afternoon for WIZ018-
030-035-036-045.

Winter Weather Advisory until 6 PM CST this evening for WIZ019-
020-022-031-037>039-048-049-074.
&&

$$

DISCUSSION.....JLA
AVIATION.......JLA

NWS GRB Office Area Forecast Discussion