259
FXUS63 KGRB 290335
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1035 PM CDT Tue Jul 28 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Small chances (10-20%) for pop-up showers or storm Wednesday
  afternoon and Thursday afternoon. No strong storms are
  expected.

- Greater chances (50-80%) for showers and storms return Friday
  into Saturday. At this time, severe weather risk is low.

&&

.DISCUSSION...
Issued at 216 PM CDT Tue Jul 28 2026

Looks quiet through Thursday as heights aloft rise. Weak
instability could yield a few pop-up showers or a storm
Wednesday afternoon, then again Thursday afternoon. No strong
storms are expected. A stronger shortwave trough is agreed upon
Thursday night through Friday. This will be the next chance for
widespread showers and some storms. Elevated mixed layer remains
well to the west though as shown by weaker mid-level lapse
rates overhead. Thus, severe weather risk looks low. Some heavy
rain potential centered on Friday with wave overhead (weaker
winds aloft) leading to slower storm motions, and since PWATs
are up to 1.75 inches which is the 90th percentile. WPC has put
the majority of our area within a marginal excessive rainfall
risk (level 1 of 4), with isolated spots in central WI into a
slight risk (level 2 of 4).

After this wave pushes through, could still see some lingering
showers on Friday. High pressure building in this weekend
results in dry weather later Saturday into Sunday.

Nothing too notable in terms of temperatures. Highs rise into
the upper 80s to near 90 on Thursday, with a moderate heat risk
showing up as heat indices will only rise to around 90. As the
upper trough is overhead on Friday with clouds and
showers/storms, temps cool into the upper 70s/lower 80s.
Temperatures will remain similar for the weekend behind the
system, then temperatures return back well into the 80s early to
mid next week.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1035 PM CDT Tue Jul 28 2026

VFR conditions are expected through the TAF period. Skies will
remain mostly clear tonight with light and variable winds. Wednesday
a scattered cu field based around 5-6kft may develop during the mid
to late morning with some isolated showers possible during the
afternoon, mainly across northern and central WI. Winds Wednesday
will gradually turn to the southwest with sustained winds of 5-10kts.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......GK

NWS GRB Office Area Forecast Discussion