525
FXUS63 KMKX 081948
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
248 PM CDT Tue Jul 8 2025

.KEY MESSAGES...

- Periods of showers and thunderstorms anticipated this morning into
this evening, though an all-day washout is not expected.

- Warm & largely dry conditions expected Wednesday through Thursday.

- Heat and humidity ramp up Friday into Saturday, accompanied by
periods of showers and thunderstorms.

- Drier and more comfortable conditions forecast Sunday into the
  beginning of next week.

&&

.SHORT TERM...
Issued 249 PM CDT Tue Jul 8 2025

Tonight and Wednesday:

Isolated showers are just starting to develop across portions of
southern Wisconsin this afternoon. The upper level and middle
level troughs are moving through to the east providing some good
lift. Diurnal heating has brought us an nicely uncapped
environment with around 2000 J/kg CAPE. There is not much shear
to speak of for most of southern Wisconsin. The best shear is
currently located along the lakeshore where the effective warm
front still resides. The shear along the lake shore is roughly
30 to 35 kts and quickly drops off to the east. Storm motion is
going to be slow as well with motion around 10 to 15 kts at
best. So a good environment for a few showers and storms.
Lightning, heavy rain and brief gusty winds are the main
concerns with any storm that develops.

The two best areas for any additional development are visible
on satellite with two bands of agitated cumulus from northwest
Dane through southeast Columbia and into Dodge and the second
line from Rock, to Jefferson and Waukesha counties. Over the
next hour or so those areas will be the place to watch for any
storms for additional rain development. Later this afternoon
into early tonight a cold front will slowly move east into the
area providing just a bit more forcing. So there could be more
scattered convection along the frontal boundary.

Rain and storm chances will end from west to east overnight
tonight as the low pressure system moves into the New England
States. High pressure will be right on its heels moving in from
the Northern Plains and into the northern Great Lakes Region.
Drier and pleasant weather for Wednesday.

Patterson

&&

.LONG TERM...
Issued 249 PM CDT Tue Jul 8 2025

Wednesday through Tuesday:

An upper level ridge will move into the Great Lakes Region Wednesday
and begin exiting to the east early Thursday. There will be some
transient mid level and sfc level features that will move
around the state. For Wednesday, low pressure will be exiting to
the east in the morning. Thursday, a stationary front will be
to our south. Large scale subsidence is winning out in the most
recent runs of guidance. Which means both features should be far
enough away from Wisconsin to keep conditions dry and pleasant.


Friday into Saturday the ridging breaks down and moves eastward as a
stronger trough and sfc low pressure system advect toward the state.
Friday afternoon into Friday night will be the best chance for rain
through the extended with POPs of     . There should be decent upper
level support as Wisconsin will be on the leading edge of this
stronger upper level low. There will be some interesting
phasing as a shortwave tries to move out ahead of the main
trough. So no shortage of upper level support, but phasing
issues could weaken the overall effectiveness for stronger
storms and broaden the window for rainfall. There is alot of
uncertainty on the track of the sfc low with some models trying
to bring it through southern Wisconsin and other opting for a
more northward track. The farther north the track goes the more
likely our forecast area is to end up in the warm sector and get
good instability for storms. Another thing to keep an eye on
for this system is moisture will be increasing and so to will
PWATs. Heavy rain will be possible with high PWATs, but this
system is expected to be more transient and move through
quicker. While no day will be a washout of rain, its a good week
to keep an eye on the forecast.

Through the rest of the weekend and into next week there is still a
lot of uncertainty so low chance POPs sneak in yet again. As
the upper level trough and sfc low exit Saturday, models are
split on the timing and strength of another trough/low right on
the heels of the first. The GFS seems to be the most amplified
and fastest, but too much uncertainty to draw meaningful
conclusions on rain/storms. Temperatures will remain consistent
through the extended with highs in the mid 70s to mid 80s.

Patterson

&&

.AVIATION...
Issued 249 PM CDT Tue Jul 8 2025

Isolated thunderstorms will be possible throughout the day and
into tonight across southern Wisconsin. The best chances for
rain and thunderstorms will be during the peak heating of the
day and as the cold front moves through later this evening into
the overnight hours. Due to the sporadic nature of
precipitation, limited the number and duration of PROB30s and
TEMPO Groups to the most likely times. VFR to MVFR conditions
are expected today. MVFR conditions with ceilings around 1-3 kft
and visibilities around 4 SM or better will be possible with
any shower or thunderstorm. A cumulus cloud deck will develop
across southern Wisconsin this afternoon with heights around 1-4
kft. Areas where the cumulus field starts to look agitated this
afternoon will likely be were we see additional development.
After the cold front has moved through, high pressure will build
in leading to dry weather Wednesday and Thursday.

Light and variable winds early this morning will become
southwesterly from the southwest to the northeast. Tonight
southwest winds will become northwesterly and then quickly
become light and variable again. Wednesday as sfc heating
increases winds will shift to northerly.

Patterson

&&

.MARINE...
Issued 249 PM CDT Tue Jul 8 2025

Low pressure is moving east along the Wisconsin- Upper Michigan
border today. The low will continue east into Lower Michigan
tonight, dragging a cold front across Lake Michigan in the
process. The front`s passage will result in a northerly wind
shift across the open waters by Wednesday morning. Periods of
showers and thunderstorms are anticipated today through tonight.
Northerly winds will be become breezy Wednesday afternoon, but
should remain below Small Craft Criteria. Northerly winds will
persist into Thursday morning, becoming light and variable
Thursday afternoon as high pressure moves across Lake Michigan.
South to southeast winds will re- establish on Friday as a
broad area of low pressure moves into the northern Great
Plains. Additional showers and thunderstorms are forecast Friday
through Saturday.

Patterson

&&

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

$$

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