NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 290600
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
100 AM CDT Wed Apr 29 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Chance (25 to 50%) of showers today and Thursday, with rainfall
  totals generally under a quarter inch through the weekend.

- Minor flooding persists on the Wolf River and Winnebago system.
  Water levels should gradually recede as the week progresses due
  to a lack of significant rainfall.

- Below normal temperatures expected through the weekend.
  Frost/freeze potential toward the end of the week.

&&

.DISCUSSION...
Issued at 1117 PM CDT Tue Apr 28 2026

Radar continues to show weak returns percolating across northeast
Wisconsin early this morning, though any evidence of showers
making it to the surface remains well off to our south. Chance
showers (25 to 50%) then return later this morning into this
afternoon as shortwave energy and attendant surface wave pivot
over the Great Lakes. A rumble or two of thunder would not be out
of the question this afternoon due to meager daytime instability
(100 to 300 J/kg MUCAPE), though remains unlikely.

The remainder of the week will be characterized by afternoon
shower chances as a blocking upper low sits and spins over Quebec,
bringing a train of shortwaves to the Great Lakes within
northwest flow regime. However, QPF should easily be held down to
a quarter of an inch or less each day. No thunder is expected due
to a lack of instability. Some CAA snow flurries cannot be ruled
out Thursday afternoon as 850 mb temps drop between -4 and -8C,
though will remain unimpactful. Weak high pressure then builds in
for the weekend, before a potent cold front brings more widespread
precip chances early next week.

Temperatures... Expect temperatures to remain below normal through
the end of the week as a cold Canadian airmass streams into the
Midwest. Highs will read primarily in the 40s and 50s during this
time. Frost/freeze concerns then come into play toward the end of
the work week as lows fall into the mid 20s to mid 30s. Will
likely necessitate headlines across portions of central Wisconsin
to the lakeshore, where the growing season/greenup have begun.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1042 PM CDT Tue Apr 28 2026

VFR cigs have gradually been filling in across much of the region
this evening. Expect that trend to continue overnight with VFR OVC
cigs expected across the region by early Wednesday morning. There is
a chance (30%) for scattered showers to develop across east-central
WI early Wednesday which may cause brief periods of MFVR cigs/vsbys
at ATW, GRB, and MTW as any showers pass over a terminal. Another
short-wave will then bring a second round of showers to much of the
region during the afternoon as it swings south over MN. Again
periods of MVFR cigs/vsbys will be possible, but the likelihood of
any IFR conditions is low (less than 10%). Forecast soundings do
show weak elevated instability (100-300 J/kg) across east-central WI
which may be enough for a few lightning strikes so did include
PROB30 groups at ATW, GRB, and MTW for -TSRA. Showers should come to
an end Wednesday evening (after about 3Z) with a mostly dry night
expected Wednesday night.

&&

.HYDROLOGY...
Issued at 1117 PM CDT Tue Apr 28 2026

Minor flooding remains limited to the Wolf River basin and the
Winnebago system, and is forecast to continue through the middle
to end of the week per RFC guidance. With a notable lack of
significant rainfall in the forecast, river levels should be
allowed to gradually recede through the weekend, with hydro/flooding
concerns becoming little to none by early next week. However,
those living near rivers or streams should continue to monitor the
latest river forecasts.

&&

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

&&

$$

DISCUSSION.....Goodin
AVIATION.......GK
HYDROLOGY......Goodin