673
FXUS63 KGRB 100722
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
222 AM CDT Fri Apr 10 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Periods of heavy rainfall and thunderstorms expected late this
  weekend through the middle of next week. There is a 85-95%
  chance of rainfall greater than 1 inch, and a 35-60% chance of
  greater than 2 inches.

- A round or two of strong to severe thunderstorms are possible
  during the early to mid part of next week, with the best chance
  occurring Monday evening.

- Minor flooding continues along the Wolf River, though combined
  runoff from melting snow in the Upper Peninsula and heavy rain
  will likely result in more widespread and significant flooding
  next week.

&&

.DISCUSSION...
Issued at 221 AM CDT Fri Apr 10 2026

Light rain associated with strong mid-level FGEN was moving
through the southeast half of the forecast area early this
morning, and should be east of the region by around 12z/Fri.

High pressure brings dry weather and low relative humidity today.
The dry conditions persist into early Saturday afternoon, with a
chance of showers arriving in NC/C WI later in the day.

A prolonged period of active weather arrives Saturday night into
Sunday and continues through the middle of next week. Periodic
showers and thunderstorms, and potential for heavy rainfall, can
be expected through the period.

The first batch of heavy rainfall arrives Saturday night into
Sunday, as a warm front lifts north into the region and a 45 to
55 knot southerly low-level jet brings a surge of Gulf moisture
(PWATs 1-1.5 inches) and marginal instability. Not seeing much
potential for severe storms during this first episode. Models
support a lull in the precipitation later Sunday night into
Monday, as H8 flow turns westerly (parallel to the baroclinic
zone), PWATs drop to less than 1 inch and instability wanes.

The front sags south and stalls across the area Monday into
Tuesday, and potentially lifts back to the north as a strong low
pressure system approaches Tuesday night into Wednesday. This
front will interact with a persistent flow of Gulf moisture and
marginal to moderate instability. Instability peaks across the
southwest half of the forecast area Monday afternoon and evening,
as MUCAPE increases to 1-2k j/kg. This instability, combined with
the frontal boundary and deep layer shear of 45-55 knots, supports
potential for severe thunderstorms. Models are not very robust
with convection Monday afternoon, but ramp up storms quickly
during the evening. Additional strong to severe storms could
develop as the front starts to lift back to the north Tuesday
afternoon and evening. If the surface low tracks far enough west
on Wednesday, we could see a surge of instability across eastern
WI as the cold front moves through in the afternoon, so cannot
rule out additional severe potential (especially damaging winds)
then. See the Hydrology section for possible flooding impacts.

Milder temperatures are expected through the period, with highs
reaching into the 70s in parts of the area Sunday-Tuesday, and
possibly even on Wednesday.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1059 PM CDT Thu Apr 9 2026

Scattered light rain will work its way from west to east through
the early overnight hours, before ending late. Conditions will
start off VFR, but will trend to MVFR overnight. MVFR ceilings
will linger into Friday morning after the precipitation ends. A
gradual return to VFR is expected on Friday afternoon as dry air
moves into the region. However, recent models show another wave
moving through, which will result in scattered to broken clouds.

Variable winds become light from the N/NW overnight into Friday,
then light again on Friday night. However, a boundary dropping
south across the bay/northern Lake Michigan will switch winds to
NE at GRB/ATW/MTW for a time later tonight. There is a low potential
(

NWS GRB Office Area Forecast Discussion