077
FXUS63 KGRB 131747
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1247 PM CDT Sun Jul 13 2025

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- Near-surface Canadian wildfire smoke will continue to result in
  poor air quality and reduced visibilities through Monday
  morning. An Air Quality Advisory remains in effect.

- Next round of more widespread active weather arrives Tuesday
  afternoon into Wednesday.

&&

.DISCUSSION...
Issued at 257 AM CDT Sun Jul 13 2025

Rain chances... Some CAMs hint at a weak surface boundary passing
over northern Wisconsin this afternoon, which could produce an
isolated shower. This being said, just as many CAMs keep us dry
throughout the day, though have opted to retain slight chance
PoPs in the forecast. Similarly, a wrung-out frontal boundary and
shallow mid-level shortwave may be enough to squeeze out a shower
or two on Monday, although any resultant rainfall would be trivial
compared to what we`ve seen over the past week. Next chances for
more widespread precip then look to arrive sometime on Wednesday,
accompanying a quasi-stationary front that sets up over central
Wisconsin. Instability and moisture build along/south of the
boundary during the afternoon as several transient shortwaves ride
along predominantly zonal flow, although heavier rain or thunder
potential would likely hinge on any north/south wobbles of the
front. Will continue to monitor in the coming days.

Smoke trends... Overnight obs show visibilities gradually rising
in response to a lull in near-surface smoke activity. This brief
reprieve will not be long-lived, however, as RAP/HRRR smoke
guidance shows another bout of elevated smoke arriving later this
morning. Some of this smoke may make it down to the surface
provided some mixing occurs, with highest concentrations across
northern Wisconsin. Westerly winds will then usher in yet another
plume from out over Minnesota Monday morning. An Air Quality
Advisory remains in effect until noon on Monday.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1247 PM CDT Sun Jul 13 2025

Smoke from Canadian wildfires will continue to move across the
region at times through the TAF period, bringing poor air quality
and mainly MVFR visibilities. The first batch will move through
this afternoon into tonight, with a break in the thicker smoke
(and the MVFR visibilities) expected to slowly work west to east
across the area later today into tonight. Another batch of thicker
smoke is forecast to move into northern WI Monday morning.
Otherwise, look for daytime cu to continue through the afternoon
then fade this evening. As a weak frontal boundary sags into and
across the area overnight into Monday morning, a stray shower will
be possible, but chances are under 20% and no impacts are
expected, so will not include. Some mid-clouds will also likely
accompany this boundary.

A period of LLWS is possible over northern WI (RHI) overnight
into early Monday as 2000 ft winds increase to 30-35 kts. It looks
marginal and short-lived, so have confined it to just a few hours
at RHI late tonight.

&&

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

&&

$$

DISCUSSION.....Goodin
AVIATION.......Bersch