NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 192303
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
603 PM CDT Sun Apr 19 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

-Minor to moderate flooding continues on several rivers, with
 major flooding expected on parts of 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 scattered thunderstorms are expected late Thursday
 afternoon through Thursday night. Heavy rainfall may accompany
 any thunderstorms. There is a 50-70% chance of rainfall in excess
 of 1/2 inch, but localized amounts to 1-2 inches could occur.

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

&&

.DISCUSSION...
Issued at 203 PM CDT Sun Apr 19 2026

A deep upper level trough was shifting east of the region, but
steep low-level lapse rates were contributing to SCT-BKN cloud
cover and lingering light sprinkles or flurries (north). Northwest
winds were also gusting to 20 to 25 mph in most areas.

High pressure builds into the region tonight, with clearing skies
and light winds leading to a chilly night. Low temperatures will
be in the teens and 20s, with localized single digit readings
possible in the typical cold spots of NC WI. As the high shifts
east on Monday, increasing south to southwest winds will bring
moderating, but still slightly below normal temperatures to the
forecast area. A weak low pressure system and cold front 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. Throughout this period, low afternoon humidity is
anticipated, which may result in an uptick in wildfire potential.

Gusty south winds develop Wednesday night into Thursday, and
start to draw Gulf moisture into the region. There is a chance of
showers and thunderstorms in our western counties by Thursday
afternoon, but showers and embedded storms become more numerous
Thursday night, as a cold front moves through. With PWATs
increasing to 1.20-1.50 inches and marginal instability (MUCAPE of
500-1000 j/kg), would anticipate locally strong storms and
potential for heavy rainfall. Current probabilistic forecasts call
for a 50-70% chance of rainfall amounts in excess of 0.50 inch.
The 90th-95th percentile forecasts show rainfall totals in the
1-2 inch range, and offer a glimpse of the higher-end potential
for this event. The frontal showers taper by Friday morning, with
scattered light showers lingering into the weekend.

Above normal temperatures persist through the mid to late part of
the work week, and the cold frontal passage only brings modest
cooling for the weekend.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 602 PM CDT Sun Apr 19 2026

Fair weather cumulus should dissipate by 02z as winds
should go light and variable during the evening. On Monday,
southerly winds will develop during the morning, and then increase
during the afternoon from 10 to 20 knots with gusts up to 30 kts.
Low level wind shear is possible Monday night.

&&

.HYDROLOGY...
Issued at 203 PM CDT Sun Apr 19 2026

Minor to moderate flooding continues on many rivers, with major
flooding expected to persist on parts of 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.

See the discussion section above for information pertaining to
precipitation forecasts for the Thursday to Friday period.

&&

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

&&

$$

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