Cassian, Wisconsin Weather Forecast Discussion

660
FXUS63 KGRB 101153
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
653 AM CDT Wed Sep 10 2025
Updated aviation portion for 12Z 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 12Z TAF Issuance
Issued at 642 AM CDT Wed Sep 10 2025
The combination of a weak cold front, short-wave trough and
abundant moisture resulted in scattered shower development
early this morning. Most locations had VFR/MVFR conditions, but
low stratus and fog (LIFR) had formed in NC WI, in the vicinity
of the cold front.
The foggy conditions should improve across NC WI this morning, but
low clouds will persist there through much of the day. Showers
will gradually taper off later this afternoon, and partial
clearing is expected during the evening.
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. The southeast part of the forecast
area will probably see a mix of VFR/MVFR conditions.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Kieckbusch
AVIATION.......Kieckbusch

NWS GRB Office Area Forecast Discussion