201
FXUS63 KGRB 160643
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
143 AM 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 today.

- There is a 20-25% chance for isolated showers and storms across
  central WI this evening, 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 143 AM CDT Thu Jul 16 2026

Smoke Trends...Widespread smoke from wildfires burning across
northern Minnesota and Ontario will continue to filter over the
region today as light winds remain north to northeasterly.
Visibility may drop as low as 1 mile at times today. An Air Quality
Advisory from the Wisconsin DNR also remains in effect until at
least noon today, 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 will be in place today. 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
this evening. 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. 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 WI 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.

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 06Z TAF Issuance
Issued at 819 PM CDT Wed Jul 15 2026

Smoke will be the main impact to aviation throughout the forecast
period. Near-surface smoke will continue to cycle over northeast
Wisconsin through at least Thursday, bringing periods of MVFR to
IFR vsbys to all of the TAF sites. An Air Quality Advisory remains
in effect through noon on Thursday. Obs are likely to pick up on
MVFR/IFR cigs as well, though this will likely be due to smoke
and not cloud cover.

Winds will eventually veer to east/southeasterly overnight, though
should remain light at around 5 to 10 knots at all terminals.

.KOSH...

Winds have continued to shift to the northeast late this evening
as a frontal boundary sinks south of OSH. Subsidence behind the
front has brought near-surface smoke to the OSH terminal, which
will persist for the duration of the TAF period. Smoke may reduce
vsbys into MVFR and even IFR territory at times, especially
Thursday morning into Thursday afternoon when smoke will be
thickest. MVFR to locally IFR cigs are forecast through Thursday
afternoon, though brief improvements to VFR will be possible
depending on smoke density.

Winds will gradually veer to east/southeast tonight into Thursday
morning, though should remain under 10 knots throughout the
forecast period.

&&

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

&&

$$

DISCUSSION.....GK
AVIATION.......Goodin

NWS GRB Office Area Forecast Discussion