137
FXUS63 KGRB 072356
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
656 PM CDT Fri Aug 7 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- There is a slight (2/5) to marginal (1/5) risk for severe
  weather this afternoon through this evening. Gusty winds and up
  to 1" hail will be the main hazards with any stronger storms.

- Several rounds of showers and storms are expected this weekend
  through early next week, though confidence in storm timing and
  severity remains low.

- Near normal temperatures in the low 80s through most of next
  week.

&&

.DISCUSSION...
Issued at 128 PM CDT Fri Aug 7 2026

Rain/storm chances...Risk for severe weather has been upgraded to
a slight risk for north-central Wisconsin, with a marginal risk
for the rest of the region this afternoon as compact shortwave
and weak cold front traverse the upper Mississippi Valley. CAM
consensus continues to show a broken line of convection developing
over northwest Wisconsin along the front during peak heating
(1,500 to 2,000 J/kg MLCAPE), progressing over the Northwoods
through the evening. However, biggest question will be whether or
not the brunt of the severe action splits us to the north, where
better deep-layer shear resides closer to the shortwave, and to
the southwest where better moisture return is. NCAR ML guidance
shows higher probs over these areas as an artifact of previous CAM
runs. Given the general consensus of the CAMs bringing these
storms through north-central Wisconsin, the higher risk for severe
weather appears appropriate. Any strong to severe storms would
mainly be a wind threat due to stout inverted-V profiles tapping
into 30+ knot winds at the top of the dry layer, with a lesser but
non-zero threat for large hail. Severe threat and confidence
diminishes further east where the marginal risk resides.

Not many changes to speak of beyond tonight as several embedded
shortwaves riding the 500 mb wave train bring multiple rounds of
showers and storms Saturday night through early next week. Most of
the moisture/instability look to remain holed up to our southwest
under western ridge; as such, better chances for more organized
convection remain where better thermodynamics are. However, period
to keep an eye on will be Sunday into Monday as surface low spins
up over the Plains and signal for better instability exists over
the western Great Lakes. ML guidance currently shows 15 to 30%
prob severe into portions of central Wisconsin during this time.
Likewise, heavy rain threat remains conditional and will likely
hinge on training storms where the boundary stalls out. As it
appears now, axis of heaviest precip Sunday into Monday looks to
target southern Wisconsin, with more of a glancing blow to our
southern tier of counties. WPC carries Marginal ERO on days 4 and
5.

Temperatures/smoke...Temperatures to read near seasonal norms in
the low 80s through the better part of next week. Elevated smoke
plume works into northeast Wisconsin preceding cold FROPA tonight,
though no significant impacts to visibility or air quality are
expected. Elevated smoke to return late Saturday into Sunday.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 637 PM CDT Fri Aug 7 2026

Scattered showers and storms across north-central and far northeast
WI should exit the region later this evening. VFR conditions
should prevail through the night as gusty southerly west winds
veer to the northwest overnight. Wind gusts up to 15 knots from
the west/northwest are expected on Saturday, then winds back to
the south/southwest late in the day. Fair weather cumulus clouds
around 4,000 feet will develop during the morning, rising to six
to eight thousand feet during the afternoon.

&&

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

&&

$$

DISCUSSION.....Kurimski
AVIATION.......Eckberg

NWS GRB Office Area Forecast Discussion