973
FXUS63 KMKX 190753
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
253 AM CDT Thu Jun 19 2025

.KEY MESSAGES...

- Isolated to scattered storms possible (15-30%) this afternoon
  into the evening.

- Overnight shower and storm chances will increase into Friday
  morning with remnant MCS moving through (50-70%).

- Additional shower/storm chances Friday afternoon (15-30%).

- Hot and humid conditions are expected for the weekend into
  early next week. Maximum heat indices of 100 to 105 degrees
  are forecast each day.

&&

.SHORT TERM...
Issued 255 AM CDT Wed Jun 18 2025

Today Through Friday night:

Early this morning some lingering showers will push out with the
low pressure system in eastern lower Michigan. Clearing skies
expected during the morning hours with drier conditions.
Into the afternoon today we will start to see a weak surface
low develop in northeast WI with some shortwave activity sliding
down the ridge behind the departing trough. While there may be
some weak WAA the main question with this will be whether there
will be enough moisture to get convection into southern WI. Most
large scale models actually keep the mid to upper levels fairly
dry. This would seem to at least prevent much in the way of
precip developing over southern WI. However, CAMs definitely
leave the door open for some development in northern WI tracking
through parts of southern WI, primarily east central WI. Any
convection pushing through southern WI looks likely to be
isolated to scattered at best but with deep layer shear around
30-40 kts we cannot rule out a stronger storm with this. The
best potential with this will be the mid afternoon through the
mid evening.

Into the late evening and overnight period things will get a
little interesting as models seems to point toward a late
evening developing MCS in central MN with this tracking
southeast overnight. The primary driver for this appears to be
the strengthening LLJ stretching into central MN. The LLJ will
swing east across southern WI into Friday morning. There will be
some shortwave activity as well but the LLJ is the primary
feature. So storms are expected to track through southern WI
late overnight into Friday morning. By the time things reach the
CWA it may very well be largely just showers with some embedded
weak storms as it encroaches on drying air and lower
instability. Linger storm potential is more likely where better
instability will be on the western fringes of the remnant MCS,
likely west of the CWA. However given the forcing and shear from
the LLJ (0-6km shear of 50+ kts) we certainly cant rule out
storms being stronger when they push in but the lack of
instability looks to be the main drawback with potential. This
appears likely to clear out by late Friday morning with another
period of clearing skies. It is worth noting that MCS formation
can be a bit uncertain with models and how things evolve is
still uncertain so it is certainly worth monitoring this as
additional model runs come in. The most uncertain aspect at this
time appears to be the timing of this remnant MCS.

Friday afternoon and evening will feature additional rain and
storms chances as strong low over the Central Plains stretches a
warm front over parts of the western Great Lakes region. In
addition we may see some shortwave energy riding down the
ridge moving overhead. Overall, models largely agree that the
best chance for activity will be further north perhaps nicking
parts of east central WI again. However, given strong deep layer
shear its worth monitoring as we could certainly see stronger
storms should any develop over the area but at this juncture
that potential seems limited in southern WI.

Kuroski

&&

.LONG TERM...
Issued 255 AM CDT Wed Jun 18 2025

Saturday through Tuesday:

The upper-level ridge axis will settle over WI this weekend
contributing to heat concerns. Model trends continue and
consistently show daytime temps in the 90s with very humid
conditions as dewpoints climb into the upper 60s and even low
70s. The combination of hot temps and muggy conditions will
likely result in heat indices climbing into the upper 90s and even
toward/exceeding the triple digits each afternoon. The hottest
temps/heat indices continue to favor southeastern WI as the stiff
southwesterly wind paired with a bit of downslope off the Kettle
Moraine will warm things up a bit more. Also it is not entirely
out of the question to see temps approach triple digits in a few
locations, but confidence remain very low at this point with
ensembles potential less than 10%. Given the consistent in the
temp and heat indices trends, will need to keep an eye on
potential headlines highlighting the heat related impacts.

Ridge axis slides a bit east for the start of next week and may
not be quite a hot, but still looking at temps in the upper 80s to
lower 90s for Monday before a cold front works its way into the
region. Timing/progression and precip associated with the
boundary will play a role on the temps for Monday and Tuesday.
However run to run variability in the frontal progression remains
in question and looks to continue to waffle around this far out on
the models. Nevertheless will be some increase PoP chances with
it and cooler temps compared to this weekend.

Wagner

&&

.AVIATION...
Issued 255 AM CDT Wed Jun 18 2025

Continue to see lower ceilings and visibility in southeastern WI
but this is projected to move out over the next few hours.
Some showers in southwest WI up toward central WI will continue
east this morning gradually dissipating with some potential
impacts to VSBYs for brief periods. Looking dry into the
daylight hours with clouds generally pushing out from west to
east during the morning become clear by the afternoon. Into the
afternoon we are looking at isolated shower/storm potential across
east central WI into the evening. This potential will continue
into the overnight period ahead of models now showing increased
potential for a dying storm system overnight into Friday
morning. This remains a bit uncertain but some storms would be
possible though likely weak given timing. Impacts to VSBYs are
the most likely especially further west where better potentially
for heavier rains and weak storms exist. CIGS are a bit more
uncertain but some MVFR CIGS would certainly be possible with
this though they are not expected at this time.

Kuroski

&&

.MARINE...
Issued 255 AM CDT Wed Jun 18 2025

Low pressure over lower Michigan will continue to track across
the eastern Great Lakes region early this morning. Expect
lighter northwest winds this morning as low pressure pushes
further east then will back to southwesterly later this
afternoon into Friday. Will continue to see stronger southerly
winds through the weekend as a deepening low pressure develops
over the Dakotas and slowly move into the Upper Midwest early
next week. Gales are not expected with this system at this time.
However, we should expect Small Craft Advisory conditions from
Saturday through most of Sunday for breezy southwest winds with
a chance on Monday as well.

Kuroski

&&

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

$$

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