Madison, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

720
FXUS63 KMKX 271450
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
950 AM CDT Sun Jul 27 2025

.KEY MESSAGES...

- Hot and humid today and Monday; a Heat Advisory may eventually
  be needed for Monday.

- Uncertain chance for MCS activity to affect the region late
  tonight and again Monday night/early Tuesday.

- Cold frontal passage Wednesday will bring cooler and much less
  humid weather to the region Thursday into the weekend.

&&

.UPDATE...
Issued 947 AM CDT Sun Jul 27 2025

Widespread fog have diminished and the Dense Fog Advisory has
been allowed to expire. Otherwise, no changes to the prior
forecast with low to mid 90s heat indices today.

Wagner

&&

.SHORT TERM...
Issued 312 AM CDT Sun Jul 27 2025

Today through Monday:

Light winds, clear skies, and plenty of low level moisture is
resulting in areas of dense fog this morning. Fog will dissipate
between 8 and 9 AM. Hot and humid conditions are expected
thereafter, with highs today warming to around 90. Heat index
values look to remain just below Advisory levels, with readings
in most locations topping out between 95 and 100.

Thunderstorms are expected to develop across northern Minnesota
this afternoon and evening, within an environment of moderate
deep layer shear and high to extreme instability. These should
form into a complex later this evening and begin to dive
southeastward into eastern Minnesota and northwestern Wisconsin.
The exact track will depend on where exactly convection forms
and at what point cold pools are able to congeal into an MCS,
but right now, the most favored track takes the MCS more or less
down the Mississippi River. This scenario would bring storms
into at least the western portion of the forecast area early
Monday morning, with frequent lightning, gusty winds, and rain.
The severe threat should decrease with time/southeastward
extent, but some stronger gusts are possible. There is quite a
bit of uncertainty with how things will play out, and details
likely won`t become evident until convection starts to take
shape this afternoon.

The potential for MCS activity also plays into the heat
situation for Monday. Right now, it looks like much of the area
will reach Advisory levels (and mainly stay just below Warning
criteria), with highs in the low 90s and heat index values
between 100 and 105. That said, more or less MCS impact could
move the needle either direction.

Boxell

&&

.LONG TERM...
Issued 312 AM CDT Sun Jul 27 2025

Monday night through Saturday:

A warm front should set up from southern South Dakota into
northern Iowa or southern Minnesota Monday evening, slowly
retreating to the south later Monday night into Tuesday morning.
There is a southwesterly low level jet nose that develops as well
into this area, shifting east during the night but weakening. A
possible mesoscale convective system may develop near these
features by late afternoon or early evening Monday, then shift
east southeast through southern Minnesota/northern Iowa and
perhaps into Wisconsin by later Monday night or early Tuesday
morning.

A couple of CAMs that go this far out are generally trying to
weaken this system as it shifts toward and into the area, as the
low level jet weakens, so there is some uncertainty with what may
occur. Have lower end (20 to 30 percent) PoPs in the forecast for
now for later Monday night into Tuesday. There is a good amount of
elevated CAPE and deep layer bulk shear, so if anything can hold
together, some stronger storms could occur. However, this complex
may weaken, so keep up with the forecast for this period.

If enough cloud cover moves out of the area by Tuesday afternoon,
there looks to be another very warm and humid day. Highs in the
middle to upper 80s with heat index values in the middle to upper
90s inland may occur. This will depend on the remnant cloud cover
from any morning precipitation moving out of the area.

A weak cold front sags southward through the area later Tuesday
into Wednesday, with the main 500 mb shortwave trough remaining to
the southwest of the area. It appears that the best upward
vertical motion may be to the southwest of the area, as high
pressure building into the region from the northwest brings
northeast winds into Wednesday and helps shunt the better
instability and moisture to the south and southwest. For now,
still have 20 to 40 percent PoPs in the forecast for Tuesday
afternoon into Wednesday, but those may need to be reduced in
later forecasts, if the drier look continues.

High pressure is then expected to settle over the region Thursday
into Friday, lingering into next weekend. This should bring more
pleasant temperatures and lower dew points and humidity, along
with dry conditions. Ensembles have been showing this trend for
several days now, so confidence is above average for this somewhat
cooler and less humid trend to occur.


&&

.AVIATION...
Issued 947 AM CDT Sun Jul 27 2025

Fog has diminished this morning and VFR conditions will prevail
through much of the period. Some mid-level cumulus (3.5-6kft)
is already developing late this morning and continue into the
afternoon. Winds will be lighter out of the south, but areas
closer to Lake Michigan may see a southeasterly wind shift and
briefly higher winds this afternoon as a lake breeze may develop
and push inland. Overnight into Monday morning there is a
potential (20-30%) to see showers and thunderstorms roll
southward down the Mississippi River Valley and may clip areas
west of MSN. However, timing and exact track remain uncertain at
this time.

Wagner

&&

.MARINE...
Issued 312 AM CDT Sun Jul 27 2025

Light to occasionally moderate south to southwest winds will
prevail into Monday. There will be additional round of showers and
thunderstorms to track across the region Sunday night into Monday
and again by the middle of the week. There may be more variable
winds accompanying any storm complex that traverses the lake
through early next week. A cold front looks to push across the
lake by Wednesday, bringing increased north to northeast winds.
High pressure around 30.3 inches should then move into the region
for the end of the week.

Boxell

&&

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

$$

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