978
FXUS63 KMKX 300358
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1058 PM CDT Tue Sep 29 2026

.KEY MESSAGES...

- Rounds of moderate rain will spread into southern Wisconsin
  tonight into Wednesday morning, with rounds of moderate to
  heavy rain at times Wednesday night into Thursday. A few
  rumbles of thunder may occur as well. The heaviest rainfall
  should occur toward the Illinois border. Rises in rivers and
  ponding of water in low lying areas are expected.

- High swim risk conditions are expected for the Lake Michigan
  beaches in Sheboygan County from middle morning to middle
  evening Wednesday. Stay out of the water during this period
  and away from dangerous areas like piers and breakwalls.

&&

.SHORT TERM...
Issued 1058 PM CDT Tue Sep 29 2026

Today through Thursday night:

A passing trough with good PVA, great mid level WAA and a LLJ,
all the items needed for a good rain here in Wisconsin. Rain is
expected to persist through much of the night and into Wednesday
morning. The LLJ is slowly tilting and moving in from the west
and so too is the mid level moisture. Dewpoints have slowly
risen across far eastern Wisconsin this evening and will
continue to do so as virga moves in and WAA continues. So while
there is rain on radar its not making it to the ground
everywhere yet, but that will come with time. We will be missing
our chemical X (instability) during the overnight hours, so
there will be a distinct lack of any thunder. With the presence
of the low level jet, we can`t completely rule out that the
forcing could be enough for a erroneous rumble or two.
Thankfully this wont mess with our perfect recipe for rain.

As the LLJ continues to tilt over the state, it will eventually
move out (topple over), running along the WI/IL border. This is
expected to happen during the late morning and afternoon hours
Wednesday which will move the forcing out of southern Wisconsin.
This should effectively bring an end to the rainfall for
southern Wisconsin as we watch it all pass just to the south.
This is expected to be temporary as the rain will return in the
evening as the forcing and lift return ahead of the next round
of rain Wednesday night into Thursday. For many it may feel as
if the day is saved... from more rain, but rest assured it will
return.

For much of Thursday, moderate to heavy rain is expected. While
this wont be much of change from Wednesday with PWAT values what
they are (1.5 to 2). What will be different is the mid level
trough axis is expected to be across southern Wisconsin and
northern Illinois and there will be added frontogenesis to help
fuel the rain machine. Soundings support this well with some
nice moist adiabatic profiles. With a lot more forcing in play
here, there is a better chance for some thunderstorms. Better
but not guaranteed, so will have to wait for the call. Rain and
any isolated storms are expected to come to an end Thursday
night as the cold front moves through the area. Drier air will
move into the state behind the cold front.

The same can be said for any flooding concerns. There is still
a fair amount of spread among guidance on where exactly the
heaviest rainfall will lie. Generally speaking were looking from
an area along or south of Interstate 94 into northern Illinois
for the axis of highest rainfall. Generally speaking rainfall
north of I-94 is expected to be less than inch with areas along
and south of I-94 around 1-3 inches. If that axis of higher
rainfall remains in southern Wisconsin its not out of the
question to see locally higher amounts up to 4 inches. As things
stand now, the best/highest chances for totals up to 4 inches
are expected along the WI/IL border. Now a saving grace in all
of this is that these are rainfall totals from tonight through
Thursday night, so this isnt coming all at once. Can`t rule out
some urban impacts with any heavier rain, of which we are
expecting. Anything larger than that we will have to keep an eye
on training and rainfall rates.

Otherwise the only other note worth item in the short term is
the high swim risk across Sheboygan County for Wednesday.
Onshore winds and building waves will pose a risk to anyone on
the beach and the subsequent Small Craft Advisory will pose a
risk to those in the nearshore waters. Stay out of the water and
away from dangerous areas (piers and breakwalls).

Patterson

&&

.LONG TERM...
Issued 1058 PM CDT Tue Sep 29 2026

Friday through Monday:

As the cold front exits to the southeast late Thursday, drier
air and high pressure is expected to move into Wisconsin. This
will bring a period of dry and cool weather across the area
through Saturday. High temperatures are expected to be in the
low to mid 60s with overnight lows in the lower to upper 40s.
Friday night will have the best potential for a chance at see
some upper 30 degree temperatures overnight.

Late Saturday into Sunday guidance as a low pressure system
passing just to the north of the forecast area. The better lift
and forcing look to remain across northern Wisconsin and Canada.
Moisture return looks to be very weak too which will further
limit the potential for any rain. While very low, opted to keep
the 10-15% chance for rain across central Wisconsin as a few
members of guidance do have the sfc low a bit further south.
Then high pressure returns keeping things cold and dry through
the rest of the extended.

Patterson

&&

.AVIATION...
Issued 1058 PM CDT Tue Sep 29 2026

VFR conditions this evening are expected to fall to MVFR to IFR
conditions tonight. Rain is slowly moving in from the west this
evening and should continue through the overnight hours into
Wednesday morning. A lull in the rain is possible Wednesday
afternoon with additional rain expected Wednesday evening into
Thursday. Ceilings and visibilities are expected to gradually
drop to around 500-800 feet tonight. Ceiling should remain at
this level through the rest of the period. Visibilities are
expected to be around 1-4 SM during the rain tonight and again
Wednesday night.

South to southwest winds are expected through the period. Winds
are expected to be breezy at times with gusts of 15-20 kts
(17-23 MPH). As a low level jet moves into tonight, LLWS will be
possible tonight into early Wednesday morning. LLWS is expected
to be out of the southwest around 40 kts at 2kft. Its marginal
and the scope will be a bit limited at times with the
occasionally breezy winds near the sfc.


Patterson

&&

.MARINE...
Issued 1058 PM CDT Tue Sep 29 2026

Southerly winds will increase tonight into Wednesday and then
become southwesterly Wednesday night into Thursday. Gusts to 30
knots will be possible over the open waters, particularly the
central and northern portion of the lake. A cold front will pass
southeast down the lake Thursday turning winds to to the north
to northeast. A Small Craft Advisory is in effect Wednesday
morning through Wednesday evening for the breezy winds and
building waves.

Strong high pressure around 30.4 inches will overspread
the Great Lakes Friday night. A fast-moving low pressure system
around 29.8 inches should move across or north of Lake Superior
Saturday night, with high pressure around 30.4 inches moving
southeast into the region by early next week. Northwest to north
winds should result across Lake Michigan. Waves may reach Small
Craft Advisory levels Friday into Saturday.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052...10 AM Wednesday to 10 PM
     Wednesday.

LM...Small Craft Advisory...LMZ643...10 AM Wednesday to 10 PM
     Wednesday.

&&

$$

Visit us at weather.gov/milwaukee

Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee