Green Bay, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

514
FXUS63 KGRB 261107
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
607 AM CDT Thu Mar 26 2026

Updated aviation portion for 12Z TAF issuance

.UPDATE...
Issued at 534 AM CDT Thu Mar 26 2026

Warmer temps holding over the north with warming temps even noted
the last couple hours over Vilas County, so at least initially
any ptype over the north will be only rain. Still a small risk for
wintry mix later this morning as has been noted well upstream in
western MN and eastern SD. Also, based on upstream radar trends,
have expanded higher likely pops farther to the south of highway
29, including much of the Fox Valley. Also, trended a few hours
slower with ending of the steadier rain over eastern WI, now not
dropping to less than likely pops until after 2p.

&&

.KEY MESSAGES...

- Light to moderate rain spreads across area this morning, ending
  as mix of light rain and snow this afternoon. Minimal snow (<
  0.5") and ice accumulations (less than 0.01") north-central WI
  into far northeast WI. Impacts limited due to warm ground and
  road temps.

- Blustery northerly winds this afternoon into this evening.
  Strongest winds 30-35 mph near the bay and Lake Michigan.

- Cool with scattered snow showers and flurries on Friday. Warming
  trends starts again this weekend with warmest days Sunday and
  Monday.

- Active much of next week with multiple opportunities for
  precipitation, including thunder, snow, ice.

- Some rivers remain above bankfull into the weekend. Potential
  for at least minor flooding may increase next week.

&&

.DISCUSSION...
Issued at 244 AM CDT Thu Mar 26 2026

Light to moderate rain today with some wintry precip on northern
edge is main focus in near term. Following today`s system will
be a brief cooldown with some light snow and flurries Friday, with
a warming trend then for the weekend into early next week. Weather
still looking active next week with multiple chances for precipitation,
which could include thunder, locally heavy rain and some springtime
snow and ice as well.

Clipper low is riding into central MN with leading cold front now
dropping into northern WI. Swath of rain tied to mid-level fgen in
right entrance region of 500-250mb jets is spreading toward
western WI and will move across central and northern WI 10z-19z.
Chances for 0.25" of QPF range from 40-80% mainly north of highway
29. Chances for 0.50" of QPF are 20-40% maximized over Lincoln and
Langlade counties. As we have seen for last few days, will be
close in terms of precip staying rain versus freezing rain, snow
over northern WI into far northeast WI. If temps in these areas
drop to freezing before bulk of rain ends this morning, could see
potential for freezing rain from near IMT toward Door County while
snow occurs over Vilas County. Even if this occurs though, fact
it will be daytime and given current road temps are in the mid 40s
there thanks to recent warmth, would not expect much in the way
of impacts. Will be something dayshift will have to monitor
though. Enough colder air works in aloft this afternoon to allow
lingering rain farther south and east to mix with and even change
to snow as the precip gradually ends. After early morning highs
around 50 in the far south, temperatures will fall through the
day, with sub freezing temps by evening over north and readings
into the mid to upper 30s elsewhere. This cooling will be driven
by strong and gusty northerly winds 20-30 mph with higher gusts
near Lake Michigan.

Temps will continue to tumble tonight, with lows ranging from the
teens north, to the mid 20s Fox Valley to the lakeshore. Wind
chills by late tonight will be as low as the single digits northern
areas. Could be a few icy spots develop with the colder temps. A
few light snow showers or flurries could occur over the north as
well through the night. Continued trend that previous shift
started by having some chances for snow showers and flurries
through the day on Friday given steeper low-level lapse rates and
models becoming locked in on another shortwave dropping through in
the colder northwest flow aloft. Will be blustery as well. That
combined with readings staying in the 30s and apparent temps in
the 20s will give the day an early spring bite, especially
compared to our recent warmth.

After a cool start Saturday morning, temperatures slowly moderate
Saturday afternoon, then begin to surge upward on Sunday as region
gets into return flow. Highs Sunday and Monday will reach the 60s
away from any bay or lake cooling.

Precipitation begins to work into the western Great Lakes region
late Monday into Monday night on leading edge of developing troughing
over western CONUS that will push stronger mid-level wind energy
into the central CONUS and eventually downstream over the Great
Lakes, Ohio Valley. Warm front well to the south to start the
week, so wintry mix of rain/snow Monday night into Tuesday is now
shown for more of the area than just the Northwoods. There are
model differences though, so this will bear watching. Warm front
makes it farther north by Tuesday/Tuesday night and this is when
chances for thunder and locally heavy rain are maximizing at this
point. Also, still enough cold air over the north for the potential
for rain, freezing rain and snow. Whether there will be a break
mid to late week behind this initial salvo of systems, or will the
systems keep coming to end the week is still uncertain. Plenty of
time to assess the details and trends, but overall looks like a
pretty active pattern is shaping up for next week.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 606 AM CDT Thu Mar 26 2026

Cold front with rain will settle across the region today,
resulting in deteriorating conditions from north to south. Though
all locations are starting the day VFR, cigs will quickly lower
to MVFR or even IFR (lowest north-central to far northeast WI).
Vsby will be MVFR to VFR as the rain moves through. The rain may
switch to a wintry mix late this morning into the afternoon over
northern WI. Precipitation will taper off to a mix of light rain
and snow this afternoon. Clouds will persist into the evening,
before scattering out later this evening into the overnight hours.

Winds are light to start the day, but as the front moves through
expect northerly winds to increase this afternoon and evening.
Gusts to 20 kts are expected at all TAF sites, with GRB/MTW
reaching 25+ kts. The gusty winds will diminish late tonight.

&&

.HYDROLOGY...
Issued at 244 AM CDT Thu Mar 26 2026

Several rivers will remain above bankfull into the weekend due to
the recent melting snow along with additional rain of 0.25 to
0.50" expected today. With a few points along both the Wisconsin
and Wolf rivers already at or near bankfull will need to watch
these possible higher end totals as they could increase the risk
for minor river flooding into next week. Additionally, we will
need to keep eye on active pattern that could develop next week.
If stronger thunderstorms and heavy rain end up occurring, potential
for at least minor flooding would further increase on many rivers,
especially as many northern areas will still have snow cover at
that point.

&&

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

&&

$$

UPDATE.........JLA
DISCUSSION.....JLA
AVIATION.......JLA
HYDROLOGY......JLA