282
FXUS63 KGRB 060004
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
704 PM CDT Sun Apr 5 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Scattered rain/snow showers this afternoon and tonight with
  additional snow showers Monday. The snow showers on Monday may
  cause brief visibility reductions/minor travel impacts.

- Next potential for widespread precipitation Tuesday night
  through Wednesday night with 20 to 50% chances for at least
  1/2 inch of rain.

- There is medium potential (40 to 60%) for additional heavier
  precipitation late next week or early the following week.

- 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 120 PM CDT Sun Apr 5 2026

This Afternoon-Tonight: Scattered rain/snow showers

GOES water vapor imagery late this morning showed a shortwave trough
diving into eastern North Dakota and northwest Minnesota. As this
wave quickly moves southeast late today and tonight, scattered rain
and snow showers (30 to 60% chance) with precipitation type
dependent on low-level boundary layer thermal profiles. Amounts will
be quite light with less than 20% chances for 0.1 inches of liquid
precipitation.

Monday-Monday Night: Scattered Snow Showers

Another quick moving shortwave trough will drop southeast Monday
into Monday evening with additional snow showers. Forecast soundings
show a relatively deeply mixed boundary layer with steep low-level
lapse rates. Cooler boundary layer profiles/steep lapse rates would
favor predominantly snow as the precipitation type. With weak
destabilization possible through the day, the snow showers may
become briefly heavy with visibility reduced to under a mile. Short-
lived travel impacts may occur within heavier snow showers and gusty
winds Monday afternoon, including during the evening commute across
the Fox Valley.

In addition, colder air will infiltrate the area Monday night with
temperatures falling into the single digits across parts of northern
Wisconsin and the teens to low 20s farther south. This will be the
coldest night on the horizon over the next week. Any water on
roads/sidewalks may freeze before temps climb back above freezing on
Tuesday.

Tuesday-Thursday: Widespread rain, starting as snow/mix.

There will be a very short break in the active weather on Tuesday as
high pressure impacts the area. However, another strong Pacific
shortwave trough will move from the northern plains to the Great
Lakes through mid-week with additional periods of precipitation
likely (60-90% chances) Tuesday night through Wednesday night. The
first round of warm advection precipitation is expected Tuesday into
Wednesday with additional precipitation with the front later
Wednesday into early Thursday. Winter impacts look minor at
this time. Precipitation may begin as snow (or a mix) Tuesday
night, but probabilities for 2 inches or greater of snow are low
right now (less than 25%) across central Wisconsin. After, rain
becomes the favored precipitation type. Through Wednesday
night, chances for at least 1/2 inch of liquid precipitation
are 20 to 50% with even lower chances for exceeding an inch.

Overall trends support the low-level boundary shifting south of the
area late in the week, which would result in drier conditions
locally. However, low (20 to 40%) precipitation chances continue
Thursday and Friday for central into east-central Wisconsin with the
uncertainty in the flow evolution and boundary placement.


Late Week: Unsettled weather continues

Looking towards next weekend, there is a signal in the global
ensemble suite for another widespread rain event across portions of
the Midwest. Southwest flow aloft is forecast to develop with
building 500 mb heights across the Great Lakes by Sunday. Mean
precipitable water values from the GEFS/ECMWF Ensemble/Canadian
Ensembles reach the 99th percentile by this time. Thus, mild
and wet conditions are supported, but confidence in more
specific details is low at this time range. CPC has highlighted
the area in a moderate risk for heavy precipitation (40 to 60%)
for next Sunday/Monday. Given the saturated conditions and
elevated river levels, this will be a period to watch.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 704 PM CDT Sun Apr 5 2026

VFR flying conditions prevailed area-wide early this evening. As a
shortwave feature moves through Wisconsin mid to late evening,
expect lowering CIGs to MVFR along with scattered rain and snow
showers to accompany this feature. Looking upstream, many of the
returns observed on current radar are not reaching the ground,
therefore continued with TEMPO groups for precip this evening,
rather than prevailing. The exception is far north-central WI
(KRHI) where snow may prevail longer. After ~06/07Z precip
dissipates, with dry weather for the rest of the night.

On Monday, another round of snow showers, some briefly heavy with
lower VSBYs, are likely.

Winds will be from the NW throughout the TAF period, with gusts of
20 to 25 kts throughout Monday morning and afternoon.

&&

.HYDROLOGY...
Issued at 120 PM CDT Sun Apr 5 2026

Many area rivers remain at/near bankfull or in minor flood stage due
to runoff from recent rounds of rainfall and melting snow/sleet.
Although additional significant precipitation is not forecast
through Tuesday, an overall wetter pattern will continue over the
next week with widespread precipitation for mid-week and potentially
another impactful rain event over the weekend or early next week.
Chances for 1 inch of rain or more are low (less than 20%) across
central Wisconsin for the mid-week system.  Given the saturated
conditions, additional rainfall will exacerbate already high water
levels.

&&

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

&&

$$

DISCUSSION.....JM
AVIATION.......KLJ
HYDROLOGY......JM/Kruk

NWS GRB Office Area Forecast Discussion