NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 241100
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
600 AM CDT Fri Apr 24 2026

.KEY MESSAGES...

- Showers are expected to redevelop on Friday especially over
  southeastern Wisconsin. Isolated storms still possible.

- Dry weather with highs in the 60s this weekend; cooler by Lake
  Michigan due to easterly winds.

- Widespread showers (80-90 percent chance) and isolated
  thunderstorms return late Sunday night through Monday night.
  Chances are fairly high for an inch of rainfall.

&&

.UPDATE...
Issued 600 AM CDT Fri Apr 24 2026

Storms have dissipated across the region, with only a few
showers lingering across southwestern Wisconsin this morning. A
cold front is currently draped across southeastern Minnesota and
eastern Iowa, and will progress eastward through southern
Wisconsin by mid-afternoon. The exact timing of this front will
dictate how high today's temperatures will be able to get, since
temperatures behind the front this morning are approximately
10-15 degrees lower than immediately ahead of it. Areas closer
to Lake Michigan stand the best chances of seeing highs in the
upper 60s today, while temperatures farther west may struggle
to get above 60 degrees today. Going into the midday hours as
temperatures in southeastern Wisconsin remain in the mid to
upper 60s, a chance for isolated thunderstorms develops.
However, this will be short lived as the front works offshore.
Severe weather is currently not expected.

MH

&&

.SHORT TERM...
Issued 1111 PM CDT Thu Apr 23 2026

Tonight through Friday night:

The line of storms is has just moved into southern Wisconsin
here this evening. Storms continue to move north northeast along
a line stretch from roughly the UP of MI through La Crosse into
eastern IA and back down to MO. MUCAPE, SBCAPE and the effective
shear are all on a downward trend here this evening as this line
of storms moves into a much weaker environmental set up. MUCAPE
is hovering around 500 J/kg with SBCAPE around 100 J/kg. Shear
is not much better around 20-30 kts at best. The scattered
storms that developed ahead of the line earlier in the night
have since merged with the line which did add in some higher
reflectivities for a bit, but this has since subsided.

Can't rule out a few stronger storms yet this evening. Until we
lose out SBCAPE the potential for a brief spin up still exists
but this chance is incredible small. Its more likely that
strong winds and heavy rain are the primary threat at this
point. This is especially true as the line of storms become
more outflow dominant over time. The window for any brief spins
ups will be over the next hour or so. The mid level lapse rates
are slowly coming down which will favor heavy rain as the night
drags on. Give the slow storm motion and current training given
the storm motion (near perpendicular to the line at this
point), urban and small stream impacts are growing. This line of
rain and storms is still expected to weak becoming more broken
with scattered to isolated storms expected. Once this happens
the flooding threat will diminish.

The cold front will slowly move down the state late tonight into
Friday morning bringing an end to any lingering showers through
the early morning hours. Severe weather is not anticipated
through Friday morning. A few rumbles of thunder will be the
primary concerns by this point. As winds turn to northwesterly
behind the front slightly cooler and drier conditions will move
into the state. Given the timing of the cold front, temperatures
may still make it into the 60s Friday. High pressure will then
slowly build into the region Friday night into Saturday.

Patterson

&&

.LONG TERM...
Issued 1111 PM CDT Thu Apr 23 2026

Saturday through Thursday:

Looking dry and quiet pattern across southern WI through the weekend
as our neck of the woods sits in between low pressures in the
Canadian Plains and Central Plains while high pressure meanders to
the northeast east of the Great Lakes. This pattern will result in
more season temps, but easterly flow off of Lake Michigan will help
keep things cooler along the lakeshore.

A more active pattern is taking shape for the start of next week as
an upper-level ridge axis pushes across the region bringing in
increasing low-level WAA later Sunday into Monday while an upper-
level trough digs across the Rockies and across the Plains. While
there is agreement on this upper-level trough lifting across the
Midwest for the start of next week, there continues to be variations
of solutions in the ensembles when it comes to timing and track
of the surface low associated with the upper-level wave. EPS is
favoring a more northward track while GEFS is a bit more south.
Depending of where this low tracks along with where the warm front
lifts/sets up will play a role in any stronger storm potential.
Otherwise, at this time expect at least increased PoPs for the
start of next week.

Then looking at a cooler pattern with potentially below normal temps
toward the middle of next week as the upper-level trough meanders
over the Central CONUS with high pressure bringing in the cooler
Canadian airmass through the end of the week.

Wagner

&&

.AVIATION...
Issued 600 AM CDT Fri Apr 24 2026

A scattered to broken deck of IFR clouds has developed in
southwestern Wisconsin, with areas outside this deck remaining
at VFR at 10k to 25k ft. A few showers have developed within the
IFR deck, with this activity expected to progress eastward
through the morning. By midday, expect any lingering IFR clouds
to have lifted to MVFR, and showers to have become scattered. An
isolated thunderstorm is possible near Lake Michigan. All
precipitation will end by mid-afternoon as a cold front exits
into the lake. Ahead of the cold front, expect southwesterly
winds. Behind the cold front, expect a rapid wind shift to
west-northwesterly. Winds will gradually shift to northerly
overnight tonight, then to northeasterly Saturday morning.

MH

&&

.MARINE...
Issued 1111 PM CDT Thu Apr 23 2026

Areas of fog are likely to continue over the lake into Friday
due to the mild, moist air flowing over the colder water of the
lake. This fog and mild air will be along modest south to
southeast winds. A warm front will stall across the far northern
edge of the lake failing to reach the UP of Michigan. This will
create a tighter pressure gradient just north of the front and
will result in winds approaching gales across the narrow area.
An occasional gale force gust will be possible until the low
pressure system around 29.2 inches and an associated cold front
pass the lake Friday afternoon/evening. A few thunderstorms will
be possible across the lake until the cold front clear to the
east. Severe weather is not anticipated at this time.

Light north winds on Saturday will then become easterly Saturday
night and Sunday before increasing into Monday. 29.4 inch low
pressure is forecast to track northeastward from the central Great
Plains (Sunday night) near or over Lake Michigan (Monday night),
with gusty east to southeast winds ahead of its arrival and gusty
west winds behind it (into Tuesday). Not seeing widespread gale
potential with this system, though trends will be monitored.

A Small Craft Advisory remains in effect through early Friday
afternoon north of Port Washington for building waves.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643 until 1 PM Friday.

&&

$$

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