NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 061047
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
547 AM CDT Sun Sep 6 2026

.KEY MESSAGES...

- A Dense Fog Advisory is in effect for Sauk County until 9 AM
  this morning. Areas of dense fog have formed in the Baraboo
  and WI River Valleys, reducing visibility to 1/4 mile or less
  at times.

- Mild and pleasant weather today and Labor Day.

- Warmer temps and high humidity return for Tuesday and
  Wednesday along with 50-80% chances for showers and
  thunderstorms Tuesday night.

&&

.UPDATE...
Issued 545 AM CDT Sun Sep 6 2026

A Dense Fog Advisory is in effect for Sauk County until 9 AM
this morning. Areas of dense fog have formed in the Baraboo and
WI River Valleys, reducing visibility to 1/4 mile or less at
times. Some patchy fog has also been observed in the Rock River
valley (near Janesville Airport) and portions of Dane county.
All of this fog should erode rapidly after sunrise given the
current lack of high-altitude cloud cover.

Some scattered clouds around 4,000 ft AGL managed to prevent fog
formation over much of eastern WI overnight.

Sheppard

&&

.SHORT TERM...
Issued 1000 PM CDT Sat Sep 5 2026

Today through Monday night:

Patchy dense fog will be possible late tonight into Sunday
morning as high pressure to the north builds in but for the
most part most of this potential should be primarily for the
western part of the CWA with lesser chances for the eastern
half. Overall outside of some fog chances overnight into the
morning over the next few days expect partly cloudy skies with
no chance for precip as we remain under high pressure with upper
level ridging overhead. While there will be a few shortwaves
passing through the overwhelming dry air in the low to mid
levels should keep things quiet though some clouds would be
expected to accompany these shortwaves.

Kuroski

&&

.LONG TERM...
Issued 1000 PM CDT Sat Sep 5 2026

Tuesday through Saturday:

Quiet start to the extended period is generally expected for
Tuesday with high pressure likely holding on through the day
Tuesday though conditions suggest that hotter and humid
conditions should return as a southerly moist flow returns.
Into Tuesday evening expect a low pressure system lifting
through south central Canada to drag a front through southern
WI. An additional low pressure forming over the southwest US
will also likely extend a warm frontal feature creating somewhat
of a stationary front slowly progressing east. There is
uncertainty on exactly where things line up and the timing and
progression but most models suggest the impact of this system is
not expected to persist beyond Wednesday. This should bring
storm chances and rain to the region especially given the decent
upper level shortwave energy in combination with some help from
the LLJ at least for Tuesday night. Into Thursday, uncertainty
increases in the surface fields but in general given dry upper
level fields despite a shortwave rolling through we could
potentially see another dry day though the moisture trends are
worth watching given that increase moisture aloft could allow
for precip. Into Friday and beyond weak flow will potentially
yield active weather possibly through the late week period into
the weekend depending on how the forcing and moisture unfold but
it will be worth monitoring through the midweek period when we
should expect a better idea of how things will go.

Kuroski

&&

.AVIATION...
Issued 545 AM CDT Sun Sep 6 2026

Areas of Dense Fog impacting KLNR, and KDLL (Baraboo and WI
River Valleys) early this morning, with some patchy fog in the
Rock River Valley (KJVL) and into Dane county (KMSN) as well.
Fog should erode rapidly after sunrise.

Otherwise, dry weather and VFR expected through the TAF period,
with light east winds today and nearly calm winds tonight. A
slight chance for fog to redevelop late tonight into early
Monday morning, mainly west of Madison.

Sheppard

&&

.MARINE...
Issued 1000 PM CDT Sat Sep 5 2026

Light to modest east northeast winds are expected into tonight.
High pressure around 30.1 inches will build into the northern
Great Lakes tonight and Sunday, shifting to the lower Great Lakes
for Monday. Light and variable winds are forecast for Sunday and
Monday.

Increasing south to southwest winds are possible Tuesday into
Wednesday, shifting west to northwest Wednesday night into
Thursday, as a cold front moves toward and through the region.
Cannot rule out a few isolated gales Tuesday/Tuesday night.

Kuroski

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Dense Fog Advisory...WIZ056 until 9 AM Sunday.

LM...None.
&&

$$

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