154
FXUS63 KMKX 240532
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1232 AM CDT Mon Aug 24 2026

.KEY MESSAGES...

- Crisp, fall-like conditions tonight. Some fog is possible
  after midnight.

- Comfortable & pleasant afternoon weather conditions today
  through Tuesday & Thursday-Friday.

- Windows for showers & thunderstorms Tuesday night through
  Wednesday & next weekend.

&&

.SHORT TERM...
Issued 1232 AM CDT Sun Aug 23 2026

Tonight through Monday Night:

With high pressure overhead, skies are clear and winds are
light. Temperatures in the low 50s to low 60s across southern
Wisconsin will continue to fall throughout the night with
overnight lows expected to fall into the upper 40s to mid 50s.
Generally warmer temperatures will be along Lake Michigan. A
nice crisp night and a taste of fall for those of us that are
looking for it. As temperatures fall there is a potential for
fog to develop tonight but there in some uncertainty in how
much fog will develop. Available moisture will be the one
competing factor for whether or not fog develops. If moisture
is lacking then dew is more likely to form than fog. Still a
bit to early to tell, but should be something that shows itself
in the next couple of hours or so as the dew point depression
drops to 1-2 degrees at multiple sites. Any fog that develops is
expected to burn off/mix out shortly after sunrise.

High pressure will slowly begin to shift east of the state,
Monday. Fair weather cumulus clouds are likely to develop again
this afternoon. Likewise under the light winds, a lake breeze is
should develop and a few miles inland. Quiet conditions are
expected through Monday night. As winds become southwesterly
behind the departing high, WAA should slowly return ahead of the
next incoming system for Tuesday.



Patterson

&&

.LONG TERM...
Issued 1232 AM CDT Sun Aug 23 2026

Tuesday through Sunday:

Heading into Tuesday, high pressure will be moving east into the Mid
Atlantic and New England states as a low pressure system travels
across southern Canada into the northern Great Lakes Region. The
upper level trough is expected to follow the exact same track as
this system becomes stacked. The surface low is expected to occluded
as it moves east before reaching the Great Lakes Region. For
southern Wisconsin, the best chance for precipitation is expected to
be with some WAA behind the warm front and with the passage of a
cold front. There is some uncertainty on how much if any rain/storms
we get with the push of WAA and any we do get will just eat away at
any instability we would have gained in the afternoon/evening. The
main concern here is the lack of any low level forcing. As temps and
moisture increases diurnally there will be instability, but nothing
to force convection. Which reflects why there are only a few model
runs with any after convection so low chance but non zero.
Especially if one shower goes, its outflow could trigger many
more. Now with the passage of the cold front there is expected
to be better upper level lit from the trough, but the timing of
this looks to occur during the overnight hours into Wednesday
late morning. This separates the best instability with the best
lift and forcing. So while rain and storms are expected due to
this confidence on any strong to severe storms are low. Its a
low but non zero chance situation. Shear looks to be the one
category that is persistent from the WAA to the passage of the
cold front in support of stronger storms. It will just come down
to timing and when our best forcing and instability resides.

The low pressure system and front are expected to clear southern
Wisconsin by Wednesday afternoon. High pressure is then
expected to return to southern Wisconsin from Manitoba on
Thursday and Friday. This area of high pressure will be exciting
to the east Friday night as another low pressure system
approaches from the Plains. This will bring rain chances back
for the weekend. An upper level trough is expected to move
through Canada with a few short wave troughs moving through the
larger flow across the Great Lakes Region. These storms chances
seem to largely be driven by the shortwave aloft and the LLJ.
Which when aligned can lead to rain and storms, but there are
some meso scale features that can throw that off or take a day
of storm potential and turn it into mostly with little
lightning. A lot of it will come down to where the best shear
and instability reside which global models seem to be washing
out and spreading out over a generous portion of the state. This
is then reflected in the low chances around 10-30%. More
details will shake out as we get closer to the weekend.

Patterson

&&

.AVIATION...
Issued 1232 AM CDT Sun Aug 23 2026

Largely VFR conditions through the period. With clear skies and
light winds tonight, there is a small potential for lower
ceilings and visibilities for any fog that develops after
midnight. There is uncertainty in how widespread the patchy fog
could become so kept mentions out of the TAFs for the time
being. If fog develops visibilities could fall to 2-4 SM.
Terminals in low lying areas or river valleys (LNR and JVL) will
have the best potential for fog development. VFR conditions are
expected to return shortly after sunrise. Fair weather cumulus
clouds are expected to return late morning through the evening
Monday. The few to scattered cloud deck is expected to be around
4-6 kft.

Light and variable winds tonight will become light northwesterly
winds Monday. A Lake breeze is expected to develop during the
early evening hours which will turn winds to the northeast then
east for lakeshore terminals. Light and variable winds are
expected again Monday night.

Patterson

&&

.MARINE...
Issued 1232 AM CDT Sun Aug 23 2026

Low pressure across eastern Ontario will linger through Monday
night which will result gusty winds across the northern third of
the lake during this time. Gusts will approach gale force at
times. As high pressure moves overhead Monday winds will become
light and variable across Lake Michigan. South to southwest
winds will set up across the lake as the high departs and ahead
of the next incoming low pressure system. The low pressure
system is expected to move through the northern Great Lakes
Region and drag a cold front across the Lake Wednesday
afternoon. Rain and thunderstorms will be possible across the
entire lake from Tuesday evening through Wednesday afternoon. A
brief period of Small Craft Conditions will be possible Tuesday
afternoon and evening ahead of the approaching low pressure
system.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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