213
FXUS63 KGRB 221103
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
603 AM CDT Wed Jul 22 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Tranquil and comfortable weather returns today through Friday.

- Warmer temperatures and higher humidity return over the weekend,
  with high temperatures climbing into the upper 80s to near 90
  and heat indices reaching into the 90s.

- Periodic chances for thunderstorms return Saturday through late
  Sunday, though timing, coverage, and severe weather potential
  remain uncertain.

&&

.DISCUSSION...
Issued at 119 AM CDT Wed Jul 22 2026

The latest RAP analysis and satellite/radar imagery show a cold front
stretching from southern Minnesota into northern Illinois early this
morning. A lingering 5000 ft cloud deck over northeast Wisconsin has
mostly dissipated, leaving mostly clear skies across north-central and
northeast Wisconsin. Upper-level troughing remains anchored over the
Great Lakes, while a broad high-pressure system over the northern
Plains is gradually dropping southeast toward the northern Mississippi
Valley.

As the surface high pushes closer to the region, winds and waves
will gradually subside early this morning. There is still a few
gusts to 25 kts over the tip of the Door Peninsula. Will let the
small craft advisory continue to expiration to ensure winds have
comfortably diminished.

For today through Friday, the high-pressure system will drift
across the northern Mississippi Valley into the southern Great
Lakes, bringing quiet and pleasant weather to north-central and
northeast Wisconsin. The western Great Lakes will sit downstream
of a strong upper ridge over the Intermountain West, placing the
area within dry northwest flow aloft. This persistent flow will
keep the deeper instability suppressed well to the south through
Friday. Expect high temperatures near or slightly below normal in
the mid-70s to lower 80s, along with cool overnight lows falling
into the 40s and 50s. Diurnal fair-weather cumulus clouds with
bases around 4000 to 6000 feet will develop each late morning and
dissipate near sunset.

For the extended period from Saturday through Tuesday, the upper-
level ridge over the western states will expand eastward toward
the Plains and Great Lakes. Return southerly flow around the
departing surface high will draw a hot and humid airmass northward
into Wisconsin. High temperatures on Saturday and Sunday will
climb into the upper 80s to near 90 degrees in central Wisconsin,
with dewpoints surging into the lower 70s. This combination will
yield afternoon heat indices approaching the mid 90s across
central and east-central Wisconsin. Positioned on the northeast
fringe of the mid-level heat dome, northeast Wisconsin will be in
a favorable corridor for periodic thunderstorm chances (20 to 50
percent) from Saturday through late Sunday. Confidence regarding
the timing, tracks, and organization of potential convective
complexes remains low at this time range. Machine learning
guidance indicates low overall probabilities for organized severe
weather, but thunderstorm trends will continue to be monitored in
future forecast updates.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 603 AM CDT Wed Jul 22 2026

High pressure building into the region today will bring quiet
aviation weather and prevailing VFR conditions across all
terminals. Clear skies early this morning will yield to scattered
fair weather cumulus around 4 to 5 kft developing between 15z and
16z. Cloud bases are expected to lift to 6 to 7 kft this
afternoon before dissipating early this evening, leaving mostly
clear skies for the remainder of the forecast period. Northwest
winds will remain light overall around 5 to 10 kts with occasional
gusts to 15 kts during the afternoon, though slightly stronger
gusts up to 20 kts remain possible near Door County. High
confidence in VFR conditions continuing through Thursday morning.

Outlook...VFR conditions will persist through Friday under dry
high pressure. Thunderstorm potential returns over the weekend.

.KOSH...
Clear skies will start out the taf period, but expect fair weather clouds
to build with daytime heating between 15-16z. Cloud bases will
initially be around 5 kft before lifting to 6-7 kft this
afternoon. Kept a tempo group for a period of broken ceilings from
16-19Z. These clouds are forecast to dissipate early this
evening, leaving mostly clear skies for the remainder of the
forecast period.

Northwest or north winds will mostly be 5-10 kts. Occasional gusts
to 15 kts are possible, most likely late in the morning.

&&

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

&&

$$

DISCUSSION.....MPC
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion