585
FXUS63 KGRB 140933
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
333 AM CST Sun Dec 14 2025

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Cold arctic air lingers today and tonight, but the coldest temps
  will depart this morning. A Cold Weather Advisory remains in
  effect for all of northern and central Wisconsin (except Door
  County) through the mid to late morning.

- Fast moving clipper system could bring a quick round of snow
  early Monday morning, mainly to northern Door County.
  Accumulations generally around an inch or less on the northern
  end of the peninsula.

- A potent system will accompany some warmer temperatures over the
  midweek, with potential for a wintry mix, rain, fog, and strong
  winds Wednesday night into Thursday.

&&

.DISCUSSION...
Issued at 333 AM CST Sun Dec 14 2025

Main forecast concerns for the upcoming week will revolve around
the lingering cold, a weak clipper early Monday, and a stronger
wintry system around the middle of the week.

Temperatures...
Bitter cold remains in place across the region this morning.
Despite some low cloud cover slowly working its way into north-
central Wisconsin, many sites across the area are still reporting
wind chill readings around -20 to -30 in the coldest spots.
Therefore, no changes planned to the current cold headlines
through the mid to late morning hours. Despite the headlines
ending in the morning, today will still be quite cold, with highs
in portions of central and north-central Wisconsin remaining in
the single digits. Fortunately, the return of some warm air
advection will keep temperatures from falling as far overnight,
but wind chill readings could still get as low as -10 to -15.

A warming trend is in the work through the work week, which should
bring some improvement on the overall conditions. High
temperatures by Tuesday and Wednesday are expected to even get
above freezing during the day!

Monday Morning Clipper...
The first chance for precipitation in the forecast will be a fast
moving but fairly decent shortwave crossing the Upper Peninsula of
Michigan Monday morning. This shortwave is progged to drop
southwestwards accompanied by some modest frontogenetic forcing
Monday morning, which could bring in some brief burst of moderate
snowfall into the region. While this feature will be limited in
area and mainly remain in the Upper Peninsula, areas right along
the border and the northern end of the Door Peninsula may see a
window for snow. Increased pops for this feature and would expect
a quick inch or less over northern Door County. Main impact would
likely be on travel, from a quick reduction in visibility, but the
rest of the forecast area would likely remain unaffected.

Midweek Clipper...
Another more potent and very dynamic system is then in the works
for the midweek period, Wednesday evening into Thursday.
Precipitation type will one of the main forecast challenges for
this system as the onset will feature a surge of strong warm air
advection overnight followed by colder air arriving Thursday
morning. Probabilistic guidance brings around 70-90% chance of
getting above freezing in the air column at 850mb, with around 80%
chance of getting above freezing across areas in the Fox Valley by
the morning hours as well as the column warms overnight. As a
result, precipitation will likely see a wintry mix develop as ice
either becomes scarce or melts. This could bring some scattered
freezing precipitation to the forecast as the ground will likely
remain fairly cold. Limiting this potential on the other hand will
be the quick arrival of colder air, as soundings do show only a
minimal window for any mix across central and north-central
Wisconsin. As any wintry mix could be highly impactful, this will
need monitoring. P-type aside, fog will also be likely as the
warmer air and higher dewpoints push across the snow pack. Winds
could also become gusty Thursday, as low level winds around 70
knots at 850mb and 50 knots at 925mb mix in at times.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1045 PM CST Sat Dec 13 2025

Mainly VFR conditions through the TAF period thanks to a bitterly
cold arctic airmass across the region. Light snow showers will be
possible at times over northern Vilas and Door Counties that
could produce MVFR ceilings and brief IFR to MVFR visibilities.
Elsewhere, mostly clear skies are expected.

W-NW winds of 10-15 knots with gusts of 20-25 knots will occur at
times through the weekend.

Low level wind shear will be possible overnight into Sunday
morning over parts of north-central and northeast WI that may
impact RHI and GRB/ATW. LLWS is once again possible Sunday night
across all TAF sites as the low level jet increases to 40 to 50
knots.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until 6 AM CST early this morning for
WIZ005-010>013-021-073-074.

Cold Weather Advisory until 10 AM CST this morning for
WIZ018>020-030-031-035>040-045-048>050.
&&

$$

DISCUSSION.....Uhlmann
AVIATION.......Kurimski

NWS GRB Office Area Forecast Discussion