811
FXUS63 KMKX 101513 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1013 AM CDT Thu Jul 10 2025

.KEY MESSAGES...

- Chances (~30-60%) for showers and storms primarily west of
  I-41 this afternoon, with storm potential overspreading all
  of southern Wisconsin this evening. Locally heavy downpours,
  gusty winds, and cloud to ground lightning are the main
  hazards.

- Active weather continues Friday into Saturday, with
  additional periods of showers and storms likely (~60-75%
  chances). Additional heavy downpours will accompany storms,
  which could lead to minor rises on area rivers and streams. A
  few strong storms with gusty winds are also possible.

- Quieter conditions prevail Sunday into the beginning of next week.

- Next storm chances return Tuesday through Wednesday.

&&

.UPDATE...
Issued 913 AM CDT Thu Jul 10 2025

An area of showers and storms approaching from the west
continues to diminish in strength this morning. It does look
like it will survive in to at least the far southwest forecast
area, so bumped precip chances up there. Storms may not make it
much past there, but redevelopment is still expected this
afternoon. Confidence has increased for afternoon storm chances
across southern Wisconsin, so nudged up forecast precip chances.

DDV

&&

.SHORT TERM...
Issued 359 AM CDT Thu Jul 10 2025

Today and Tonight:

Synopsis/Mesoanalysis: A surface ridge remains entrenched over east-
central and southeast Wisconsin this morning, resulting in light and
variable surface winds across the eastern half of the area. Given
the light winds, areas of patchy fog are possible once again through
daybreak, particularly in low-lying spots. 3 AM surface observations
show a warm front weaving from central Iowa into northwest Illinois.
Said boundary is forecast to work north into southern Wisconsin
today, allowing for a more humid air mass to overspread the region
by this evening. Widespread showers and storms are ongoing from
southwest Minnesota into the Missouri Valley, and will continue to
progress east through the early morning hours. The broad area of
convection has modified the broader environment, with satellite and
radar imagery showing an affiliated MCV currently rotating over the
Sioux Falls, SD vicinity. The MCV is expected gradually move east
today, pulling close enough to the area to support shower and storm
development by this afternoon. Expect most shower and storm activity
to remain west of Interstate 41 through the afternoon hours, with
precip chances overspreading all of southern Wisconsin this evening.
Lift from the remnant MCV will be reinforced by increasing 850 mb
winds & warm advection tonight, supporting additional shower and
thunderstorm potential areawide through daybreak Friday. A few
storms developing this afternoon could be strong to severe, with
damaging wind gusts being the primary concern. Heavy downpours will
be possible in any storms that develop this afternoon through
tonight, which could lead to isolated urban/small stream flooding &
minor rises on area rivers and creeks. Stay weather-aware if
planning to be outside this afternoon and evening.

Rest Of Overnight: Patchy fog remains possible through sunrise,
though current trends suggest coverage will be smaller compared to
last night. Thus anticipate that the best fog potential will remain
confined to low-lying spots & within the Wisconsin River Valley.
Slow down & use low beam headlights if encountering areas of fog on
the road through sunrise.

Today: The warm front currently to the southwest of the region will
gradually work in from late morning through the afternoon, allowing
a muggy and unstable air mass to build in from west to east. The
returning/unstable air mass will be intersected by the MCV currently
to the west of the area, resulting in shower and storm development
by the early afternoon hours. Expect that activity will remain
largely confined to south-central and southwest Wisconsin through
most of the afternoon, as this will be where the overlap of
instability and MCV-related lift will be greatest. Storms will be
developing within a moist environment characterized by 1.3-1.5"+
precipitable water values, making heavy downpours a possibility in
any activity. Deep layer shear is expected to be modest at-best in
the near-storm environment, with forecast soundings generally
showing 10-15 kts. Thus expect storm organization to be messy in
this afternoon`s activity, making gusty winds in collapsing cores
the primary severe weather impact. Will nevertheless be monitoring
the progression of the warm front & its interaction with any storms,
as forecast hodographs do show some elongation & enhanced curvature
in the vicinity of the boundary. If a storm were able to interact
with the front, there`s a low chance (~2% within 25 miles of a
point) that it could briefly begin to rotate. This potential would
be far secondary to that of gusty winds, and would remain confined
to areas southwest of Madison, where the warm front will arrive
during peak heating. Thus anticipate that gusty winds, heavy
downpours, and cloud to ground lightning will be the main concerns
in this afternoon`s thunderstorms.

Tonight: Afternoon thunderstorms will work into portions of east-
central and southeast Wisconsin during the evening hours, with
additional thunderstorm development anticipated areawide through the
overnight hours. Deep layer shear will be a touch higher (~15-25
kts) relative to this afternoon, though strong/severe hazards will
become limited by a stabilizing boundary layer. Thus anticipate that
heavy downpours and cloud to ground lightning will be the primary
hazards in overnight storm activity. The continued heavy downpour
potential could lead to minor hydro impacts (urban/small stream
flooding & small rises on rivers/streams), particularly in any
locations experiencing training or multiple rounds of activity from
the afternoon and overnight rounds.

Quigley

&&

.LONG TERM...
Issued 359 AM CDT Thu Jul 10 2025

Friday through Wednesday:

Uncertainty does still exist for the Friday and Saturday system, but
certain details are starting to gain more confidence. An upper level
trough and shortwave will advance from the Plains and southern
Canada for the start of the weekend. Guidance has been consistent on
the shortwave pulling out ahead of the larger trough and moving
through Friday. As the shortwave moves in a sfc warm front is
expected to lift north over southern Wisconsin Friday morning. A few
showers and storms will be possible along the leading edge of the
warm front, but the better chances around 50-70% are expected to be
with a stronger push of mid level WAA and when the upper level
shortwave moves in Friday late afternoon.
The elongated trough will be right on its heals bringing PVA into
the state through Friday night and into Saturday.

The upper level trough will swing through Saturday and at the sfc a
low pressure system is expected to move east into the northern Great
Lakes Region. As the sfc low moves east a cold front will move
through Wisconsin, bringing more rain and thunderstorm chances. The
frontal boundary is expected to be slow moving and could move in as
early as the wee hours Saturday for the northwest corner of our CWA.
The slower this front moves in and progresses east southeast the
more the higher the chances for some environmental destabilization
for eastern Wisconsin. If we get some more warm air and instability
out ahead of the cold front then there will be a higher chance for
thunderstorms and the potential for more than one round of
rain/storms for eastern Wisconsin. If movement is that slow then
rain could linger through Saturday afternoon for eastern Wisconsin.

Less humid and quieter conditions will move in behind the front for
Saturday night and Sunday. Temperatures will remain in the upper 70s
to mid 80s through the weekend. Heading into early next week another
warm front is expected to approach Wisconsin and winds will shift to
southwesterly. WAA will start up again bringing a return of hot and
humid conditions. Uncertainty grows on the timing of this front, how
strong WAA is and the track of an approaching low pressure system
from roughly the Central Plains.
Will have to keep an eye on the chances for more precipitation for
early to mid next week.

Patterson

&&

.AVIATION...
Issued 913 AM CDT Thu Jul 10 2025

An area of showers and storms approaching from the west
continues to diminish in strength this morning. It does look
like it will survive in to at least the far southwest forecast
area, so bumped precip chances up there. Storms may not make it
much past there, but redevelopment is still expected this
afternoon. Confidence has increased for afternoon storm chances
across southern Wisconsin, so nudged up forecast precip chances.
Periods of showers and storms may then persist through the
evening and overnight hours. Locally heavy rain and stronger
winds will be possible with any stronger storms that develop.

Light south to southeast winds will persist through tonight,
becoming more easterly near the lake this afternoon as a lake
breeze pushes in. Southerly winds will pick up a bit Friday.

VFR conditions will largely persist through Friday, though
models do show a potential period of lower ceilings late tonight
into early Friday.

DDV

&&

.MARINE...
Issued 359 AM CDT Thu Jul 10 2025

1015 mb high pressure continues to linger across Lake Michigan this
morning, resulting in light and variable winds across the waters.
Winds will shift out of the south-southeast this evening as a broad
area of 1004 mb low pressure moves into the northern Great Plains.
Southerly winds will persist through Friday as low pressure moves
into the upper Mississippi River Valley. Periods of showers and
thunderstorms are forecast from this evening through Friday. A few
storms could produce strong wind gusts. The aforementioned area of
low pressure, along with an accompanying surface front, will move
across Lake Michigan Friday evening through Saturday afternoon,
bringing additional shower and thunderstorm chances. Similar to
storms developing today through Friday, a few stronger storms are
possible, with gusty winds being the primary hazard. Winds will
shift out of the west Saturday evening behind the departing frontal
boundary. Generally west winds will continue through Sunday
afternoon as 1015 mb high pressure moves into Iowa.

Light and variable winds continue into this afternoon in nearshore
zones. Winds will turn southeasterly this evening ahead of low
pressure moving into the northern Great Plains. Periods of showers
and thunderstorms are forecast from this evening through Friday
afternoon as the low moves into the upper Mississippi Valley. A few
strong storms with gusty winds are possible. The surface low will
progress across Lake Michigan Friday night through Saturday,
dragging a cold front across nearshore zones in the process.
Additional periods of showers and storms will are forecast during
this time frame. A few additional strong storms are possible, with
gusty winds being the main concern. Keep tabs on the forecast
through Saturday afternoon if planning to take to the water.

Quigley

&&

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

$$

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