NWS-Green Bay Forecast Discussion
FXUS63 KGRB 061203
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
703 AM CDT Mon Apr 6 2026
Updated aviation portion for 12Z TAF issuance
.KEY MESSAGES...
- Scattered snow showers today. Some of the snow showers may be
heavy and cause brief visibility reductions/minor travel
impacts.
- Next potential for precipitation Tuesday night through Wednesday
night. Probabilities for at least 0.50 inch of liquid
precipitation between 20-50%, and for at least 0.5 inch of snow
between 20-40% mainly north and west of the Fox Valley.
- Potential is increasing for additional heavier precipitation
late this weekend into early next week. Probabilities for at
least 1 inch of rain between 50-70%.
- Minor flooding will continue along some rivers this week due to
recent rainfall. Additional precipitation over the next week may
exacerbate flooding in some areas.
&&
.DISCUSSION...
Issued at 356 AM CDT Mon Apr 6 2026
Scattered Snow Showers Today...This morning's surface
observations and satellite and radar imagery indicated flurries or
sprinkles were falling from a low stratus cloud deck at times,
which coincided with a 500mb vort max over the area. This 500mb
vort max will exit the region later this morning, but another one
is progged to move into the area by midday in addition to a
surface boundary beginning to drop south over the area. Paired
with steep low-level lapse rates and some surface instability,
CAMs remain on track with diurnally driven scattered snow showers
developing over the area. Inverted-V forecast soundings would also
indicate these bursts of snow would produce gusty winds of 25 to
30 mph, with slightly higher gusts to 35 mph over the Door
Peninsula. Given these favorable parameters, the snow showers may
become briefly heavy with visibility reduced to under a mile
through the early evening, which may impact the evening commute.
Warmer roads may limit travel impacts, but as air temperatures
fall below freezing into this evening some cooling of the roads
should still occur. Some slippery spots on untreated roads,
bridges, overpasses, and sidewalks may still occur during the
evening. Any of the snow showers will come to an end a few hours
after sunset with the loss of daytime heating and as high pressure
moves into the area. Snow accumulations will remain on the lighter
side with a dusting to a couple tenths of an inch in most spots,
but upwards of an inch in Vilas County due to this morning's
lingering lake-effect snow showers.
Colder air will trail behind this boundary tonight causing
temperatures to fall into the single digits in far north-central
WI and the teens to low 20s farther south.
Midweek Precipitation...Low-level southwest flow ahead of a low
pressure system/cold front looks to generate some WAA driven
precip over the area Tuesday night into Wednesday. Forecast
soundings indicate there may be a brief period of a wintry mix at
the onset of this precipitation before surface temps/boundary
layer temps warm above freezing. By Wednesday morning, locations
north and west of the Fox Valley could see some snowfall as probs
for at least 0.5 inch of snow are between 20-40% in these areas.
This will be follows by pre-frontal rain occurring between
Wednesday afternoon and Thursday morning. Probabilities for at
least 0.50 inch of liquid precipitation are between 20-50%, with
lower chances in far north-central WI.
Rest of the forecast...High pressure will be dominant over much of
the area on Friday, but there are indications of the southern
portions of the forecast area seeing some precip from a system
tracking south of the area. An unsettled pattern looks to set up
late this weekend into early next week, causing the potential for
heavier precipitation to increase, which long-range ensembles
support with probabilities for at least 1 inch of rain between
50-70% area-wide. Given the saturated conditions and elevated
river levels, this will be a period to watch.
&&
.AVIATION...for 12Z TAF Issuance
Issued at 702 AM CDT Mon Apr 6 2026
While some clearing occurred in east-central WI this morning, a
mix of VFR and MVFR cigs prevailed over central WI. Across north-
central WI, isolated snow showers were producing IFR cigs/vsbys.
These snow showers will remain isolated this morning with periods
of MVFR cigs and IFR vsbys moving across the region. By this
afternoon, the snow showers will become more scattered and heavier
with possible IFR cigs and LIFR vsbys at times. Multiple TEMPO
groups have been used at all TAF sites since the lower cigs/vsbys
will occur at times. Outside of any snow showers, VFR or high-end
MVFR conditions will prevail. Flying conditions will improve as
the snow showers come to an end late this evening.
Northwest winds will prevail through the TAF period. Gusty winds
are expected from this morning through this evening, peaking
around midday with gusts of 20 to 25 kts. However, within the
heavier snow showers, winds may gust up to 35 kts. Winds subside
late this evening.
&&
.HYDROLOGY...
Issued at 356 AM CDT Mon Apr 6 2026
Many area rivers across central and eastern WI remain at/near
bankfull or in minor flood stage this morning due to runoff from
recent rounds of rainfall and melting snow/sleet. The Yellow,
Peshtigo, Oconto, Embarrass, and other rivers/streams in eastern
WI will level off and slowly fall the next couple of days. The
Wolf, especially near Shiocton, will continue to slowly rise into
mid-week. No rivers are forecast to reach moderate flood stage. No
river flooding is expected across north-central WI, where less
rainfall fell and some snow is still on the ground.
The isolated rain/snow showers today will not have any impact on
the flooding. The Tuesday night and Wednesday system will bring a
little more substantial rain, but current probabilities of over
0.5" of rain (or liquid equivalent) are only between 30-50%
(highest in central WI). We will have had at least a couple days
to dry out, which will allow more water to push through the
rivers. So while the additional rainfall could slow the fall of
some river levels slightly and possibly create some minor low-
land flooding, no additional significant flooding is anticipated.
Will need to keep an eye on next weekend and/or early next week
as the flow turns southwesterly again, ushering in PWATs over an
inch and possible rounds of heavier precip, which could bring a
more substantial flooding threat.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Kruk
AVIATION.......Kruk
HYDROLOGY......Bersch