NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 201100
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
600 AM CDT Thu Aug 20 2026

.KEY MESSAGES...

- Dry and pleasant conditions today with drier air in place.

- Shower/storm chances return early Friday morning through the
  day.

&&

.UPDATE...
Issued 600 AM CDT Thu Aug 20 2026

Some patchy fog this morning for low-lying areas and river
valleys. Otherwise, previous forecast remains on track with
high pressure working its way across the area today and shower
and storm chances return by early Friday morning and continuing
through the day Friday.

Wagner

&&

.SHORT TERM...
Issued 1100 PM CDT Wed Aug 19 2026

Tonight through Friday night:

Given some weak high pressure overhead tonight we should see
some fog develop over parts of southwest and south central WI
with models generally pointing toward those areas as a focus for
fog development. Dense fog is not expected at this time.
Thursday looks to be on the quiet side overall with that weak
high pressure remaining in place long enough to keep things dry
through the day. Thursday night and into Friday we expect a
weak surface low to swing through with instability to bring some
storms though likely to be weak given weak shear. The forcing
with this seems largely focused along the a shortwave with
enough forcing for showers and weak storms the only real concern
is whether the moisture will be widespread enough to make
precip chances more widespread. Right now on Friday chances have
been somewhat limited in southwest extent with better chances
toward central WI and as the front pushes east moisture seems to
improve into Friday afternoon and evening. This likely pushes
out for the most part some time Friday night.

Kuroski

&&

.LONG TERM...
Issued 1100 PM CDT Wed Aug 19 2026

Saturday through Thursday:

Models suggest a weak chance for precip chances to linger into
Saturday as weak low pressure pushes out particularly on the
eastern side of the CWA but generally models push the moisture
and the vast majority of forcing from the upper level wave
having already pushed out. Generally Saturday should feature
high pressure nudging into the region keeping things for the
most part on the drier side. Sunday and Monday the high pressure
further builds into the region keeping things dry through
Monday. By late Monday night into Tuesday we will see our next
best chance for showers and storms as and 850mb front and upper
level shortwave swing through with some WAA. Still some
uncertainty in track and such but models generally agree on this
pushing through bringing precip with likely some storms as well.
In addition, deep layer shear appears to be strong in the
40-50kt range which would bring some severe risk if the timing
of storms is into the evening.

After Tuesday, uncertainty increases quite a bit though in
general higher pressure seems to be pushing in with drier
conditions overall more likely.

Kuroski

&&

.AVIATION...
Issued 600 AM CDT Thu Aug 20 2026

Outside of some patchy fog for inland terminals for another
hour or two, expect VFR conditions to prevail across southern WI
with light and variable winds as high pressure works trough the
area today. Then will see more southwesterly winds develop
overnight into Friday as shower and thunderstorm chances
increase from the northwest after 07-10z. Any shower and
thunderstorm activity will bring lower visibility and light to
moderate rainfall through Friday morning and then scattered
chances for the rest of the day.

Wagner

&&

.MARINE...
Issued 1100 PM CDT Wed Aug 19 2026

Light to modest winds are expected into Thursday, as high
pressure around 30.0 inches tracks through the western Great
Lakes region. As the high exits to the southeast later Thursday
into Thursday night, south to southwest winds will develop.
Gusty southwest winds, as well as shower and thunderstorm
chances, return Friday into Friday night, as low pressure around
29.8 inches moves across the region and drags a cold front
through. Gusty winds will shift to the northwest later Friday
night into Saturday after the front moves through. High pressure
around 30.2 inches moving toward the region later in the
weekend may help maintain gusty north winds.

Kuroski

&&

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

$$

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