Montello, Wisconsin Weather Forecast Discussion

028
FXUS63 KMKX 251937
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
237 PM CDT Thu Sep 25 2025
.KEY MESSAGES...
- Patchy fog in river valleys and other low lying areas possible
  again tonight.
- Above normal temperatures return late week into the weekend.
&&
.SHORT TERM...
Issued 237 PM CDT Thu Sep 25 2025
Tonight through Friday night:
Clear skies, high pressure, and lows dropping toward the
dewpoint values tonight will allow for areas of dense, shallow
fog again. This should occur in the usual low lying areas,
marshes and river valleys.
A weak mid level shortwave will track southeast through
northern MN and central WI tonight, with the associated surface
low dropping across Lake Superior and northern Lower Michigan.
This feature may help prevent or break apart any fog that has
developed toward central WI. A weak surface cold front is
expected to reach Sheboygan around 10 AM, Milwaukee around 12
PM, and Kenosha by 3 PM. The timeline may accelerate with this
back door cold front, rushing down the lake quicker than inland
areas. It should reach Madison between noon and 3 PM, although
diffused in strength.
The steep low level lapse rates behind this cold front should
give us an area of low clouds along and behind the front for the
afternoon and evening, and possibly through the night. That
cloud layer looks fairly shallow on forecast soundings, so
sprinkles are possible, but showers unlikely. Northeast winds
along and behind this front may have a few gusts up to 20 mph,
and persistent onshore winds could build wave heights up to 3
feet, but a beach hazards statement does not look necessary at
this time (moderate swim risk). High temps tomorrow will be
impacted by the front and these associated clouds, with
lakeshore temps only in the lower 70s and southwest WI temps in
the upper 70s.
The cloud cover is uncertain for Friday night. Where it is
clear, fog is possible once again.
Cronce
&&
.LONG TERM...
Issued 237 PM CDT Thu Sep 25 2025
Saturday through Thursday:
Another trough of low pressure will swing across the Upper Great
Lakes Saturday afternoon. Expect slightly breezy southwesterly
winds ahead of this trough, along with a push of warmer air.
Highs over southern WI Saturday will be in the lower 80s. Expect
northerly winds behind the front Saturday evening, with temps
falling back into the lower 50s for most areas. An area of
clouds is likely along this front, but probably no showers since
the deeper forcing is way farther north.
High pressure will sit over the Upper Great Lakes Sunday and
Monday. Temperatures will continue to be well above normal for
late September, around 80 inland from Lake Michigan. Plenty of
sunshine, light winds and a lake breeze can be anticipated each
day. This will also continue to be a good setup for morning fog.
By Tuesday afternoon, surface high pressure sitting over
Ontario and Hudson Bay will push cooler air across Lake Michigan
on a northeast breeze. The forecast remains dry for southern WI
Tuesday through Thursday. A low pressure trough approaching from
the Northern Plains may bring precip to us next weekend.
Cronce
&&
.AVIATION...
Issued 237 PM CDT Thu Sep 25 2025
The afternoon diurnal cumulus clouds will diminish quickly this
evening. Areas of fog, locally dense, are expected once again in
the favorable low spots and river valleys. A weak cold front
will spread into east central WI Friday morning, race down the
lake through late morning, and gradually spread inland as well.
Expect a period of MVFR ceilings along and behind this "back
door cold front" from mid Friday morning through mid Friday
afternoon. There should be improvement to cloud bases up to VFR
by mid afternoon. Clouds may linger into the overnight hours,
but there is uncertainty. If clouds clear, especially for areas
inland from Lake Michigan, then areas of dense fog are possible
once again.
Cronce
&&
.MARINE...
Issued 237 PM CDT Thu Sep 25 2025
Westerly winds are expected tonight as high pressure slides
across Illinois and Indiana. Areas of fog are possible again
tonight. A frontal boundary associated with a surface trough
will then drop through Lake Michigan from the north on Friday,
with winds becoming northerly behind the front. Wind gusts up to
20 kt are possible, along with building waves up to 3 feet
along the WI and IL Lake Michigan shoreline. This is not high
enough for a Small Craft Advisory.
Light southerly winds will prevail on Saturday as the weak high
departs and a low pressure trough crosses Manitoba and Ontario.
Winds will become northerly Saturday night. High pressure  will
set up over the Upper Great Lakes Sunday and Monday, leading to
light and variable winds with a lake breeze each day.
Cronce
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&
$$
Visit us at weather.gov/milwaukee
Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee

NWS MKX Office Area Forecast Discussion