779
FXUS63 KGRB 161753
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1253 PM CDT Thu Jul 16 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Air quality and visibility will continue to be degraded by smoke
  from wildfires burning across northern Minnesota and southwest
  Ontario through at least Friday.

- There is a 20-25% chance for isolated showers and storms across
  central Wisconsin late tonight; no severe storms are expected.

- Isolated to scattered thunderstorms are expected Friday
  afternoon and evening (60-80% chance). A few storms could become
  strong to severe, mainly across northern WI, with threats of
  damaging wind gusts, hail, and locally heavy rain.

- Another round of thunderstorms is possible (40-60% chance)
  Monday. Predictability of any of these storms becoming severe is
  low.

&&

.DISCUSSION...
Issued at 1252 PM CDT Thu Jul 16 2026

Smoke Trends...Widespread smoke from wildfires burning across
northern Minnesota and Ontario will continue to affect the region
through at least Friday as light winds remain north to
northeasterly. Visibility may drop as low as 1 mile at times. An
Air Quality Advisory from the Wisconsin DNR also remains in effect
until at least noon Friday, and may need to be extended for at
least parts of the forecast area.

With upper-level flow remaining predominantly northwesterly
through this weekend and into next week periods of smoke will be
likely over the next several days. However, surface winds will
briefly become southerly Friday which could shove much of the
smoke east allowing for at least some improvement to visibility
and air quality.

Thunderstorm chances...A nearly stationary surface boundary
generally along the I-94 corridor is currently in place.
Southwest of this boundary moderate to strong destabilization is
expected to develop this afternoon. This will create at least a
low-end (20-25% chance) for a few isolated thunderstorms across
central Wisconsin tonight. However, with weak forcing/surface
convergence and lack of stronger deep layer shear the risk for any
stronger storms is low.

Storm chances do uptick on Friday (60-80% chance) as a series of
short-waves are progged to pass over the region. This activity
will draw the aforementioned stalled boundary northward as a warm
front during the day Friday. CAMs generally show this warm front
advancing as far north as Lake Superior by Friday afternoon with
strong destabilization (MLCAPE 1500-2000 J/kg) to its south.
Recent CAMs generate showers and thunderstorms ahead of the warm
front across north-central Wisconsin Friday morning. These storms
are expected to remain below severe limits as instability will be
fairly limited.

Forcing for ascent and deep layer shear are expected to increase
late Friday afternoon into the evening as a more dynamic short-
wave dives across Lake Superior and drags a cold front across the
forecast area. This will create at least a marginal environment
for strong to possibly severe storms to develop, mainly across
northern Wisconsin and the UP. Storm mode is relatively uncertain
at this point, but if any discrete supercells are able to develop
up to one inch hail, damaging wind gusts, and locally heavy
rainfall would be possible. Forecast hodographs from north-
central WI also show enough low-level curvature to support a low
probability tornado threat. That threat is expected to decrease
with eastward extent as storms may tend to grow more into a
cluster. One note for this period is smoke trends will be import
to monitor Friday in regards to the degrees of destabilization
that is able to occur.

Ridging will return largely dry conditions to the region for this
weekend. Another chance (40-60%) for showers and storms arrives
Monday with the passage of another front and upper level speed
max. Predictability on if any storms become severe is low.

A surface ridge will then generally bring dry conditions to the
region for the rest of next week.

Temperatures...Temperatures will remain above average into early
next week, although cooler than prior days. Peak heat indices at
times may reach 90 in spots but thicker smoke may limit daytime
temperatures and heat indices to some degree over the next few
days.

A cooler, drier airmass is favored by the middle of next week
within the deeper northwesterly flow aloft.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1228 PM CDT Thu Jul 16 2026

Smoke remains the main impact to aviation throughout the forecast
period. The smoke continues to create IFR vsbys at most terminals
late this morning. Minor improvement of vsbys is possible this
afternoon and evening as the boundary layer become more mixed, but
some deterioration is then expected again late tonight. Finally
there are some indications that more pronounced visibility
improvements will occur from southwest to northeast on Friday
afternoon.

Surface obs may also continue to show MVFR ceilings at times,
however, these ceilings are tied to smoke rather than clouds.

The latest models indicate that showers and isolated storms are
forecast to develop over southwest Wisconsin late this afternoon
before moving northeast across the region after midnight into
Friday morning. Confidence is very low with this scenario due to
smoke impacts, but will continue to monitor trends.

Light southeast winds through tonight will veer to the southwest
on Friday and generally remain 10 kts or less through the end of
the TAF period.

.KOSH...

IFR visibilities from smoke will continue to impact KOSH through
the TAF period. It`s possible that visibilities will rise to MVFR
for a time this afternoon and evening, but confidence is rather
low if/when that will occur.

Surface obs will also continue to show MVFR ceilings at times,
however, these ceilings are tied to smoke rather than clouds.

The latest models indicate that widely scattered light showers
and isolated storms are possible after midnight through Friday
morning. The highest probabilities seem to occur in the time
periods from 08-11Z and 15-18Z. Probabilities are generally 20% or
less, so will refrain from adding a prob 30 group into the TAFs.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion