Plainfield, Wisconsin Weather Forecast Discussion

402
FXUS63 KGRB 101657
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
1157 AM CDT Wed Sep 10 2025
Updated aviation portion for 18Z TAF issuance
.KEY MESSAGES...
- Showers gradually taper off today.
- Areas of fog, locally dense, possible the next couple nights.
- Chances for showers and thunderstorms arrive for the start of
  the weekend, but dry weather returns Saturday night and Sunday.
- Above normal temperatures from Friday through next Wednesday.
&&
.DISCUSSION...
Issued at 406 AM CDT Wed Sep 10 2025
A cold front stretched from SW MN to NW WI to the western U.P.
early this morning. Ahead of the front, showers were ongoing
across GRB CWA, in response to short-wave energy and PWATs of
1-1.3 inches. Widespread low stratus and fog had formed along and
behind the front, including in far NC WI.
Initial negatively-tilted short-wave over GRB CWA will bring
showers before departing early this morning. A positively-tilted
short-wave will drift across the forecast area for the rest of the
day, as the weakening cold front sags slowly southeast across the
forecast area. This will bring additional isolated to scattered
showers into the afternoon. Little instability is expected, so
have pulled any mention of thunderstorms out of the forecast. With
abundant cloud cover anticipated through the day, have lowered
high temperatures into the middle 60s to lower 70s for today.
High pressure builds into the region tonight and lingers until
Friday, when it begins to shift northeast. The surface ridge will
reside over the northwest half of the forecast area late tonight,
and this will be an area of concern for possible dense fog
development, especially in the climatologically favored
Wisconsin River Valley. A repeat performance for fog, possibly
dense is anticipated over northern WI Thursday night.
The high pressure system will edge east Friday night into
Saturday, allowing the front to return as a warm front. Scattered
showers and thunderstorms are expected to develop as this occurs.
The best chance will be across C/EC WI Friday night, as a short-
wave trough tracks through the region. Additional convection could
occur in our southwest counties Saturday afternoon as surface
based instability develops near the warm front. Dry weather
should return late in the weekend as strong ridging aloft builds
across the western Great Lakes. The chance of showers and storms
returns as the upper ridge shifts east next week and southwest
flow brings a more moist and unstable air mass and periodic short-
wave energy to the western Great Lakes. Suspect that the current
low-end blended model pops will come up a bit with subsequent
forecasts.
Temperatures will remain close to normal through Thursday, then
rise above normal from Friday through next Wednesday, with highs
reaching the upper 70s and lower 80s in most areas.
&&
.AVIATION...for 18Z TAF Issuance
Issued at 1157 AM CDT Wed Sep 10 2025
Scattered very light showers and drizzle continue along a weak
cold front early this afternoon. Most locations north of the front
have LIFR/IFR conditions, while VFR conditions persist south of
the boundary. Widespread low stratus remains solid over northwest
Wisconsin, the Upper Peninsula, and Lake Superior.
Have extended the chance of very light rain (20-30%) into early
this evening from north-central to far northeast WI. RHI/AUW/CWA
have the highest chances of seeing a very light shower, but no
impacts are expected.
The front will gradually drop southeast tonight and lose
definition in the process as high pressure builds in from the
north. But because winds are so light, there is no push of dry air
into the region. The high pressure, light winds and remnant
moisture will result in potential for widespread fog development
over much of NC/C/NE WI late tonight. The fog will likely become
dense in spots, with LIFR/VLIFR flight conditions.
Lowering ceilings and IFR/MVFR visibilities will be possible over
the Fox Valley and lakeshore as well, but confidence is lower as
5-7 kft clouds are expected to linger along the front into late
tonight. Did add IFR visibilities to GRB/ATW based on RAP cross-
sections.
Fog and low stratus will begin lifting in the 14-15z timeframe.
Slow improvement of flight conditions is expected on Thursday
morning.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Kieckbusch
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion