356
FXUS63 KGRB 251937
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
237 PM CDT Sat Apr 25 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Another round of moderate to heavy rain with embedded storms
  is forecast for Monday into Tuesday. Locally heavy rainfall
  between 1 and 2" will be possible.

- Rivers are expected to rise next week after a round of moderate
  to heavy rain early in the week.

- Stronger storms are possible Monday afternoon and evening. A few
  of the storms could produce hail.

&&

.DISCUSSION...
Issued at 237 PM CDT Sat Apr 25 2026

Fairly tranquil pattern expected through Sunday evening, although
a few sprinkles are possible into this evening based on latest
radar trends. Models showing weak upper level feature moving with
the mean flow to trigger the elevated showers. For later tonight,
low clouds across Lake Michigan are expected to spread
northwestward due to southeasterly low level flow. This is
supported by the MET/LAV guidance showing low clouds moving into
the area after midnight. The biggest question is how far northwest
the low clouds will make it. Any low clouds should erode by mid to
late morning with ample sunshine allowing temperatures warming
into the 60s away from the bay and Lake Michigan.

Meanwhile, low pressure developing across the central plains
Sunday afternoon will move northeast toward the state Sunday
night. The chances of rain will be on the increase late Sunday
night and Monday, then come to an end Monday night as a cold
front moves across the area. Highest rain chances are set at
90-100% Monday afternoon into Monday evening. There is a 60-70%
chance of 1" or more along and south of Highway 29. There is a
20-30% chance of 2" or more across central WI. The Storm
Prediction Center has portions of central and east-central WI
in a Marginal Risk Monday afternoon and evening. Dry conditions
should prevail Tuesday through Saturday, with cool night and
temperatures at least a few degrees below normal each afternoon.
With the drying conditions, fire weather concerns could develop
late in the week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1204 PM CDT Sat Apr 25 2026

Areas of MVFR/IFR CIGS near the bay and Lake Michigan should erode
during the afternoon with VFR conditions into this evening.
However, low clouds IFR/MVFR are likely to develop again later
tonight across northeast WI, especially from KGRB/KATW/KOSH east
to Lake. Low confidence the low clouds would making it to
KAUW/KCWA/KRHI. Otherwise, VFR conditions should prevail over
the rest of the area through Sunday evening.

&&

.HYDROLOGY...
Issued at 237 PM CDT Sat Apr 25 2026

Minor flooding continues on several rivers, namely the Wolf and
Menominee. Minor flooding was occurring on the Fox River at
Oshkosh. Dry conditions should prevail through Sunday evening,
with increasing chances of rain late Sunday night into Monday.
Widespread rainfall amounts of 0.75 to 1.25 inches is expected
with locally higher amounts. There is a 60-70% chance of 1" of
rain along and south of Highway 29. There is a 20-30% chance of
2 inches of rain across central WI.

Per RFC forecasts and HEFS guidance, it appears that the
Menominee River could return to moderate flooding at Mc Allister
where the probably of this occurring at 10%. Continuing snow melt
from the Upper Peninsula would lend some confidence for at least
a return to moderate flood stage.

Due to less rainfall, the Wolf River is no longer expected to get
back to major or even moderate flood stage, even with the expected
rainfall. Levels on the Lake Winnebago system continue to rise
due to inflow from the Wolf and Fox Rivers, with minor flooding
already occurring from Lake Poygan to Winnebago and minor flooding
forecast to occur through the weekend. Those living near rivers
or streams should continue to monitor the latest Flood Warnings
and statements from the National Weather Service in Green Bay.

&&

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

&&

$$

DISCUSSION.....Eckberg
AVIATION.......Eckberg
HYDROLOGY......Eckberg

NWS GRB Office Area Forecast Discussion