Greenleaf, Wisconsin Weather Forecast Discussion

167
FXUS63 KGRB 300300
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
1000 PM CDT Mon Sep 29 2025
Updated aviation portion for 06Z TAF issuance
.UPDATE...
Issued at 737 PM CDT Mon Sep 29 2025
Dewpoints have crept up late this afternoon and early this
evening and range from the middle 50s to middle 60s across the
region. Many locations across north- central WI and a few
locations across far northeast WI are already approaching 100%
relative humidity with nocturnal cooling setting in. It`s
possible that a Dense Fog Advisory will be needed later this
evening or overnight, and trends will be monitored.
&&
.KEY MESSAGES...
- Areas of fog, locally dense, will impact the region tonight into
  early Tuesday morning. The fog may result in locally hazardous
  travel conditions for the early morning commute on Tuesday.
- Dry conditions prevail through at least Friday, with a chance
  of showers and isolated thunderstorms arriving Friday night into
  Saturday, and continuing at times through Monday.
- Above to much above normal temperatures anticipated through the
  next week.
&&
.DISCUSSION...
Issued at 243 PM CDT Mon Sep 29 2025
Mostly sunny skies covered the region this afternoon, with
temperatures ranging from the middle 70s near Lake Michigan to the
upper 70s and lower 80s elsewhere. The latest surface analysis
showed a Canadian cold front sagging south through northern
Minnesota and northern Lake Superior.
A weak back door cold front will drop south across the region
tonight, with greater potential for areas of fog and patchy dense
fog as a shallow cooler air mass arrives and winds become light
from the east to northeast overnight. The fog could pose localized
travel hazards for the Tuesday morning commute. Lows are expected
to drop into the upper 40s to middle 50s in most areas.
Canadian high pressure will ridge across the Great Lakes region
through the rest of the work week, and will be slow to shift east
due to the blocking influence of a couple tropical systems in the
western Atlantic. Tonight`s cold frontal passage will bring a
minor cooling trend mid-week, followed by much above normal
temperatures for the end of the work week and the weekend.
Dry conditions persist until Friday night or Saturday, when a
chance of showers and isolated thunderstorms arrive in conjunction
with a weakening cold front. Another more significant cold front
is expected to move through late Sunday night into Monday, so
periodic showers and isolated storms should continue into early
next week.
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 06Z TAF Issuance
Issued at 1000 PM CDT Mon Sep 29 2025
Confidence is increasing for areas of IFR/LIFR conditions
developing overnight.
Most locations remain VFR late this evening, but a few locations
have seen ground fog develop already. Expectations remain that conditions
will deteriorate after 06Z as fog develops and spreads. Areas of
IFR/LIFR conditions for both visibility and ceilings are expected
through sunrise. Conditions will improve to VFR between 13Z and
14Z Tuesday as fog dissipates. VFR is expected for the remainder
of the afternoon with light E/NE winds.
Outlook...
VFR conditions are expected to continue into Tuesday night.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.........MPC
DISCUSSION.....Kieckbusch
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion