NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 212323
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
623 PM CDT Tue Apr 21 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Dry weather is forecast through Thursday, which will continue
  the gradual drop on area rivers.

- Temperatures will be well above normal through Friday, with
  highs in the 70s to around 80 degrees on Thursday.

- Scattered showers and thunderstorms are expected Thursday night
  into Friday. Heavy rainfall may accompany any thunderstorms,
  with a 15-35% chance of exceeding an inch of rain.

&&

.DISCUSSION...
Issued at 247 PM CDT Tue Apr 21 2026

Hard to find a cloud across the forecast area this afternoon as
most locations have clear blue skies. Satellite imagery at 19Z
showed a few daytime cu starting to pop up in far northeast WI.
Expect a similar trend across east-central WI over the next few
hours. Any place with scattered cu development will see these
dissipate after sunset.

Dry weather continues through Wednesday and Thursday with upper
level ridging over the western Great Lakes and surface high
pressure to the northeast. Mostly sunny skies persist on
Wednesday, but warm advection clouds will start to stream in on
Thursday. Temperatures will also trend upward, peaking on Thursday
with highs in the mid 70s to around 80 degrees, aside from near
the bay and lake which will be cooler.

With the warmer/drier weather in place RHs today and tomorrow
are/will be in the 20-30 percent range, resulting in a slight
uptick in wildfire potential. However, winds remain light.

The next opportunity for rain and thunderstorms is late Thursday
evening into Friday as a cold front moves across the state. The
timing has slowed down slightly, making conditions unfavorable
for strong or severe storms as instability starts to wane. Most
models show precip arriving after 06Z, at which time soundings
show a long, skinny elevated CAPE profile of 600 J/kg at most.
However, pwats will be increasing to 1.2 to 1.4 inches Thursday
night, which means locally heavy rain will be possible within any
shower or thunderstorm. NBM probabilities remain about the same,
with a 15-35% chance of more than 1" of rain. Probabilities for
more than 2" of rain are around 5-10% in central WI, and near zero
elsewhere. Lingering showers will end Friday afternoon and
evening, followed by another stretch of dry weather through the
weekend with temperatures slightly above normal.

Looking ahead, a low pressure system could bring another round of
showers and thunderstorms Monday into Tuesday. Probabilities of
exceeding 1" of rain are similar, around 15-35%.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 615 PM CDT Tue Apr 21 2026

VFR flying conditions will persist through the TAF period.

Scattered high-based cumulus and cirrus clouds will move through
eastern WI this evening, otherwise clear skies are anticipated.
Moderate NW-N winds will impact our western TAF sites early this
evening, while E-SE winds prevail in eastern WI due to lake
breeze boundaries. Winds will become light and variable overnight,
then increase again from the SE late Wednesday morning and
afternoon.

&&

.HYDROLOGY...
Issued at 247 PM CDT Tue Apr 21 2026

Minor to moderate flooding continues on many rivers, with major
flooding expected to persist on parts of the Wolf River through
tonight. Most of the river levels have crested, and with a
prolonged stretch of dry weather anticipated through Thursday,
water levels should gradually subside through the week.

Those living near rivers should continue to monitor the latest
Flood Warnings and statements from the National Weather Service
in Green Bay.

&&

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

&&

$$

DISCUSSION.....KLJ
AVIATION.......Kieckbusch
HYDROLOGY......Kurimski/KLJ