Dewey, Wisconsin Weather Forecast Discussion

494
FXUS63 KGRB 132019
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
319 PM CDT Sat Sep 13 2025
Forecast discussion for routine afternoon forecast issuance
.KEY MESSAGES...
- Areas of fog late tonight into early Sunday morning. Fog may be
  dense at times, resulting in locally hazardous travel.
- Mainly dry with above normal temperatures through early this
  week. Chances of showers and thunderstorms during the mid to
  late part of the week, with a significant cool down possible
  Friday and Saturday.
&&
.DISCUSSION...
Issued at 317 PM CDT Sat Sep 13 2025
Pesky stratus that formed on north edge of outflow from morning
storms over southern Lake Michigan is lingering from the Fox
Valley to the lakeshore. These clouds will scatter out later this
afternoon. High pressure settling overhead along with mostly clear
skies and light east winds will lead to areas of fog overnight.
Greatest risk for dense fog per HREF probabilites is over northern
WI where temps are expected to fall into the lower 50s. Farther
south and east, may be just enough wind in the boundary layer to
lead to stratus with patchy fog instead of widespread fog.
Additionally a lot of guidance is showing marine fog re-developing
and moving onshore. Not enough confidence to issue dense fog
advisory, but at least for some areas, certainly could be needed.
Fog and stratus will diminish by mid morning Sunday, though based
on recent trends if marine fog does form, it would probably take
longer to dissipate.
Dry weather then should hold through Tuesday as sharp ridging builds
aloft. Temperatures Monday and Tuesday will be well above normal,
with readings in the low to mid 80s. Nighttime lows will also be
well above normal, with readings in the upper 50s to lower 60s.
Beyond Tuesday, a low pressure and stronger cold front will gradually
work across the plains, crossing the Great Lakes Thursday into Friday.
The upper trough is positively tilted throughout, so winds aloft are
not strong and thus shear ahead of the front remains weak at best.
MLCAPES up to around 1000J/kg are likely on Wednesday afternoon and
evening, so scattered thunderstorms are possible, but limited shear
ultimately lowers the severe threat. Additional chances for showers
and storms occurs on Thursday as the front moves through. After well
above normal temperatures early in the week, decent signal that readings
fall back to normal or at least slightly below normal by Friday on into
next weekend.
&&
.AVIATION...for 18Z TAF Issuance
Issued at 1247 PM CDT Sat Sep 13 2025
Rain cooled air flowing north out of earlier storms over southern WI
and Lake Michigan has resulted in scattered to broken low MVFR stratus
developing over much of east-central WI, including the Fox Valley.
Expect this stratus to scatter out the rest of the afternoon. VFR
conditions will prevail this evening, but areas of fog and stratus
should redevelop in the late evening and overnight hours, resulting
in IFR/LIFR conditions in many areas. The fog and low stratus
will diminish by 14z-15z on Sunday, leaving VFR conditions the
rest of the day.
SE winds of 5 to 10 kts are expected this afternoon, becoming light
from the E tonight into Sunday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....JLA
AVIATION.......JLA

NWS GRB Office Area Forecast Discussion