Seneca Cors, Wisconsin Weather Forecast Discussion

464
FXUS63 KGRB 272305
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
605 PM CDT Sat Sep 27 2025
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- An extended period of dry and low-impact weather is forecast
  through Saturday. Above average temperatures are expected during
  this time.
- Patchy frost is expected in north-central Wisconsin late
  tonight into early Sunday morning. Patchy fog may also occur
  in central and north central Wisconsin.
&&
.DISCUSSION...
Issued at 319 PM CDT Sat Sep 27 2025
A cold front was moving through the forecast area this afternoon,
accompanied by a narrow band of stratocumulus clouds. Ahead of the
front, temperatures had warmed into the lower to middle 80s, while
temperatures were only in the upper 60s and lower 70s in its wake.
Dew points also dropped off rapidly behind the front, with
locations in north central down into the 30s and lower 40s.
High pressure will build into the region in the wake of the
front, with clear skies, light winds and a very dry air mass
supportive of cool overnight temperatures tonight. Have kept
cooler Min temperatures in the forecast tonight, with lows in
the middle 30s in parts of north central WI, where patchy frost
is expected overnight into early Sunday. Patchy fog may also
develop in the Wisconsin River Valley areas of north central and
central WI, but given the dryness of the air mass, it should
develop later (09z-13z/Sun) with less visibility restriction than
recent nights. Dry and warm conditions, along with low relative
humidity, can be expected Sunday into Monday.
Another cold front drops south across the region Monday night,
with Canadian high pressure ridging across the region through the
rest of the week. This will result in briefly cooler, but still
above normal temperatures mid-week, and continued dry conditions
as the high persists through the end of the week. A couple
tropical systems off the East Coast of the U.S. will only serve
to block the eastward progression of the high, which may delay
precipitation chances until next Saturday night or Sunday.
Winds will pick up a bit out of the southeast Wednesday night
into Thursday, leading to possible marine concerns (Small Craft
Advisories) on Lake Michigan, especially south of Two Rivers.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 604 PM CDT Sat Sep 27 2025
High confidence in VFR conditions prevailing across all terminals
for most of the TAF period. A cold front will exit northeast
Wisconsin this evening, ushering in a very dry continental
airmass. High pressure building in from the west will create
ideal radiational cooling conditions overnight after a narrow band
of clouds along the front departs.
THROUGH 14Z SUNDAY...
Clear skies and light surface winds are expected across the area.
The primary forecast challenge revolves around fog potential
overnight. However, with a very dry airmass moving into the region
(dewpoints in the 30s and 40s), the risk for widespread fog is
minimal. Model guidance shows little to no signal for fog
development. While patchy ground fog cannot be entirely ruled out
at KRHI, KAUW, KCWA, impacts should be relatively brief as any fog
should mix out at or around 13Z.
AFTER 14Z SUNDAY...
Continued VFR with widespread sunshine throughout the day on
Sunday. Surface winds will become north to northeast around 5 to 8
knots as high pressure centers over the state. No aviation
hazards are anticipated.
OUTLOOK...
Clear skies are expected to continue into Sunday night, with no
significant weather events impacting aviation anticipated through
Monday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Kieckbusch
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion