734
FXUS63 KGRB 020350
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1050 PM CDT Tue Jul 1 2025

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Next chance for rain and a storms will be Wednesday afternoon
  and evening. A few storms may become strong.

- Additional chances for rain and storms will be possible Thursday
  through the holiday weekend, with the best chance for widespread
  active weather moving through sometime on Saturday.

- Temperatures will be above normal through the week, with very
  warm and humid conditions arriving for the 4th of July.

&&

.DISCUSSION...
Issued at 234 PM CDT Tue Jul 1 2025

Weak ridging will keep conditions dry across the region through
the rest of the day today and should allow for clear skies again
overnight.

Attention then turns to the next chance for rain which will
arrive Wednesday afternoon and evening. Diurnal heating is
expected to hit convective temperatures in the early to mid
afternoon, producing around 1000-2000 J/kg surface based CAPE
ahead of a relatively weaker upper shortwave. Hodographs show
relatively some modest speed shear around 30-40 knots through the
column by the afternoon and evening, which may assist any
convection in the area. Would expect some rain and thunderstorms
to cross the region, with the best potential still focused around
central to north-central Wisconsin during the peak heating hours.
This may pose a brief severe weather concern, with damaging winds
posing the main concern followed by hail. A few meso models do
sustain any showers and thunder into the early overnight hours,
but would expect any severe potential to drop off rapidly as
surface based instability wanes with sunset.

A warm front will lift into the region Thursday, bringing with it
a warm, muggy, and unstable airmass that will last into Saturday.
As a result, diurnal heating may produce some isolated to
scattered convection again Thursday and Friday, but more organized
storms seem unlikely at this time. Instead, the best potential
will arrive along the next cold front on Saturday. Model timing
remains uncertain at this time, but general consensus continues to
focus on the latter half of the day. If the timing of
the wave coincides with peak heating, strong to marginally severe
storms could develop, though weaker deep layer shear of 20 to
25 kts remains a mitigating factor. Active weather then appears to
again depart the region around the end of the weekend into next
week.

A very warm holiday weekend lies ahead as well. Temperatures will
rise back into the upper 80s by Thursday, with low 90s possible
both Friday and Saturday. As a result, heat indices could get into
the middle 90s.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1049 PM CDT Tue Jul 1 2025

Good flying conditions with clear skies and light westerly winds
are expected through Wednesday morning. By midday Wednesday, a
scattered cu field will develop with cloud bases around 5000-7000
ft AGL. Scattered showers and isolated thunder are also
anticipated to drop south/southeast during the afternoon. Given
the scattered nature of the convection, continued PROB30 groups at
all TAF sites, except RHI where confidence remains higher. A
brief wind shift from the west to the northwest will accompany
the convection and the potential to produce gusts to 25 kts.
Models are showing signs of another wave of convection tracking
southeast across the area after sunset. With less confidence in
this evolution, have only included PROB30 groups at the central
and north-central WI TAF sites.

&&

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

&&

$$

DISCUSSION.....Uhlmann
AVIATION.......Kruk