NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 181901
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
201 PM CDT Sat Apr 18 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

-Minor to moderate flooding continues on many rivers, with major
 flooding expected on the Wolf River through Tuesday. Water levels
 have crested in most areas, and due to an extended period of dry
 weather, a gradually drop is anticipated through the week.

-Showers and thunderstorms are likely Thursday night into Friday.
 There is a 40-60% chance of a quarter inch of rain, and a 20-30%
 chance of a half inch.

-Temperatures will be be below normal through Monday, with much
 above normal temperatures in the 60s and 70s expected Tuesday
 through Friday.

&&

.DISCUSSION...
Issued at 201 PM CDT Sat Apr 18 2026

A deep upper level trough was moving through the region, and was
supporting BKN-OVC stratocumulus and cool temperatures in the 30s
and lower 40s across the forecast area. Northwest winds were
gusting to 25 to 35 mph regionwide. Cool temperatures in the
upper 30s and

Winds will subside this evening, with skies briefly scattering
out. Increasing mid-level clouds are expected overnight as a
short-wave trough approaches the region. This wave, which looks
fairly potent, will bring a chance of light snow showers or
flurries to parts of central and east central WI Sunday morning.
At best, we are expecting a light dusting of snow.

High pressure builds into the region Sunday night. As the high
shifts east on Monday, increasing south winds will will bring
moderating, but still slightly below normal temperatures to the
forecast area. A weak low pressure system and cold front will move
through the region with little or no precipitation on Tuesday.
Much warmer gets drawn into the region ahead of the front, with
high temperatures rising into the 60s and lower 70s. High pressure
returns Tuesday night into Wednesday, with continued dry and mild
conditions.

Gusty south winds develop Wednesday night into Thursday, and start
to draw Gulf moisture into the region. There is a small chance of
showers in our western counties by Thursday afternoon, but showers
and thunderstorms become more likely Thursday night into Friday,
as a cold front moves through. With PWATs increasing to 1.00-1.25
inches and marginal instability (MUCAPE of 500-1000 j/kg), would
anticipate fairly widespread showers and embedded storms, with
potential for locally moderate to heavy rainfall. Current
probabilistic forecasts show a 40-60% chance of amounts in excess
of 0.25 inch and 20-30% chance of greater than 0.50 inch.

The cold frontal passage brings some modest cooling for the
weekend.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1203 PM CDT Sat Apr 18 2026

VFR stratocumulus with ceilings of 3500-4500 ft AGL will
gradually rise during the day and scatter out by this evening.
Increasing mid-level clouds will arrive ahead of a short-wave
trough later tonight into Sunday morning. The short-wave may
combine with steep mid-level lapse rates to produce scattered
light snow showers or flurries over central and east central WI
Sunday morning.

Northwest winds will continue to be blustery this afternoon with
frequent gusts to 20 to 25 kts and peak gusts around 30 kts.
The winds will subside early this evening, then increase again
mid-morning Sunday, though they will not be as strong as today.

&&

.HYDROLOGY...
Issued at 201 PM CDT Sat Apr 18 2026

Minor to moderate flooding continues on many rivers, with major
flooding expected to persist on the Wolf River through Tuesday.
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.....Kieckbusch
AVIATION.......Kieckbusch
HYDROLOGY......Kieckbusch