NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 081153
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
653 AM CDT Wed Apr 8 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Light mixed precipitation may bring slippery roads in parts of
  central, north-central and far northeast WI for the morning
  commute. Moderate rain overspreads the region late this
  afternoon and evening.

- Gale Warning in effect on Lake Michigan late this morning
  through this evening.

- Potential for heavy rainfall and thunderstorms late this weekend
  into early next week. Probabilities for 1 inch or more of rain
  are 50-80%, with a 15-35% probability of 2 inches or more.
  Strong to severe storms possible Monday afternoon and evening.

- Minor flooding continues along a few rivers this week, but
  runoff from melting snow in the Upper Peninsula and heavy rain
  may result in more widespread and significant flooding by the
  early to middle part of next week.

&&

.DISCUSSION...
Issued at 231 AM CDT Wed Apr 8 2026

Radar returns have been increasing across the southwest third of
WI early this morning, in response to increasing WAA/isentropic
lift on the nose of a 40-50 kt low-level jet. Lingering dry air
(dew points in the middle teens to lower 20s) and lack of deep
saturation was inhibiting precipitation development, with ground
truth reports of precipitation only seen in far southern WI and
northern IL. Surface temperatures were in the upper 20s and lower
30s, leading to precip type concerns.

RH timesections show deeper saturation occurring from SW to NE
across the area between 08z-11z/Wed, so would expect to start
seeing some precip reports in the next hour or so. Overall, the
forecast has not changed much, with a light mix of snow/sleet
changing over to freezing rain/rain this morning. Like last night,
there was enough evidence to warrant an increase in sleet
probabilities in the forecast. Still expecting most areas to get
a dusting to a half inch of combined snow/sleet, with a light
glaze of ice occurring over central, north central and far
northeast WI. Though we don't have much road temperature data to
work with, it is expected that ice accumulations will be spotty
on area roads, with minor threats occurring on bridges,
overpasses and secondary roads. This may result in locally
hazardous travel conditions for the morning commute in C/NC/far NE
WI. Surface temperatures look to warm enough for all rain by late
morning, as this first round of precipitation exits northeast WI.
A second round of moderate rainfall arrives with a cold frontal
passage and short-wave trough during the late afternoon in north
central and central WI, and the evening across northeast and east
central WI. There may be just enough forcing and instability for
a few rumbles of thunder in eastern WI this evening.

Mainly dry weather returns late Wednesday night through Saturday,
with the exception of a 30-60 percent chance of light rain
over the southern half of the forecast area Thursday night. The
main forcing mechanism with this event will be strong mid-level
FGEN.

A prolonged period of potentially significant rainfall arrives
Saturday night into early next week, with deep southerly flow
leading to an influx of Gulf moisture. PWATs increase to 1.2-1.4
inches across the region Sat night into Sunday, with marginal
instability (MUCAPE of 500-1000 j/kg) arriving Sunday into Sunday
night. Perhaps the most impactful period occurs Monday afternoon
and evening, as a strong cold front moves through. MUCAPE of 1-2k
j/kg and strong deep layer shear (45-55 kts) will be in place,
setting the stage for a round of strong to severe thunderstorms.

Milder temperatures are expected through the period, with highs
possibly reaching into the 70s Sunday into Monday.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 646 AM CDT Wed Apr 8 2026

A light mix of snow, sleet, freezing rain and rain will change to
all rain and end by mid to late morning. Localized MVFR flight
conditions will accompany the precipitation, but a return to VFR
is expected for the late morning and afternoon. A swath of
moderate rain will shift west to east across the area late
Wednesday afternoon and evening, accompanied by MVFR conditions.
Most places will see a return to VFR after the rain ends, but MVFR
ceilings may continue across north central WI overnight.

Strong LLWS will continue across the region until the cold front
moves through this evening. Ahead of the front, strong south
winds will gust to 25 to 35 knots, then veer SW-W and decrease
after the frontal passage.

&&

.HYDROLOGY...
Issued at 231 AM CDT Wed Apr 8 2026

Minor flooding continues on the Wolf River early this morning.
Precipitation amounts of a quarter to half inch today and tonight
will maintain saturated conditions and high water levels and fast
flows on area rivers for a few days. A mainly dry period is
anticipated from Wednesday night through Saturday, but potential
for heavy rain and thunderstorms arrives later in the weekend
through early next week. During this upcoming period,
probabilities for rainfall in excess of 1 inch are 70-90%, and
15-35% for amounts in excess of 2 inches. Runoff from this
rainfall, combined with snowmelt from the Upper Peninsula and far
northern WI, is expected to bring potential for more widespread
and significant flooding issues heading into the middle of next
week. Right now, it appears the most significant flooding impacts
may occur on the Menominee River and its tributaries.

&&

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

&&

$$

DISCUSSION.....Kieckbusch
AVIATION.......Kieckbusch
HYDROLOGY......Kieckbusch