900
FXUS63 KMKX 120817
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
317 AM CDT Sat Jul 12 2025

.KEY MESSAGES...

- Lingering showers this morning gradually diminish.

- Another chance (20-45%) for a broken north to south line of
  showers and thunderstorms this afternoon/early evening,
  especially east of I-39/90.

- Dry weather expected Sunday into early Tuesday, then turning
  warmer and more active with precip chances returning midweek.

&&

.SHORT TERM...
Issued 315 AM CDT Sat Jul 12 2025

Today and Tonight:

Showers with a few embedded rumbles of thunder continue across
southern WI early this morning as the mid-level shortwave trough
gradually works its way out of the area. Will continue to see
this shower activity through daybreak, but as the trough shifts
further east, will see coverage gradually diminish as well.
Behind the showers, likely to see cloudy and misty conditions
linger through the morning as well. A drier window is expected
mid to late morning, but another upper-level trough is progged
to swing through the Upper Midwest through the day. This will
be accompanied by a weak cold frontal boundary moving through
the region.

Ahead of the cold frontal passage will see southerly winds and
lingering moisture with PWATs around 1.5 inches across southern
WI. As the trough and cold front move through, could see a north
to south orientated broken line of showers develop along the
front early this afternoon into early evening hours. 00z HREF
does show a narrow swath of modest SBCAPE (500-1200 J/kg) build
in behind the morning activity and ahead of the frontal passage.
Thus may be enough for a few showers to grow tall enough to
produce thunder/lightning this afternoon as well. While the
potential for stronger storms is limited (SPC risk 1 out of 5)
given the favorable upper-level dynamics remaining north and
east of southern WI, cannot rule out seeing an isolated storm or
two tap into the 30-40 kt 0-6km shear expected to work its way
into the region and produce localized gusty winds and small
hail. While today does not look to be a washout with plenty of
dry time, the 00z CAMs support a quick window for this activity
along the cold front this afternoon generally between 20z-00z.
Drier conditions expected behind the frontal later this evening.

Otherwise, looking a near normal if not slightly cooler
conditions today given the cloud cover and scattered
shower/storm chances. Looking at highs today in the upper 70s
and lower 80s with overnight temps behind the cold front
falling into the upper 50s and lower 60s.

Wagner

&&

.LONG TERM...
Issued 315 AM CDT Sat Jul 12 2025

Sunday through Friday:

An upper trough will exit into southeastern Canada and the
overall pattern will trend more zonal to start the next
workweek. Surface high pressure will dominate our weather
regime, though only for a brief time as the western CONUS ridge
begins to break down toward midweek. A series of shortwaves will
ride the remnant, flat ridge over the northern tier of states,
opening our low level flow back to the southwest and bring a
seasonably warm/muggy airmass back into the region. High
temperatures Monday through Wednesday will trend a few degrees
above average, with highs in the mid to upper 80s and heat
indices getting into the 90s.

Timing midweek rain chances is rather futile given typical
differences within the guidance, though the main idea is to
expect a few bouts of showers/storms from later Tuesday through
Thursday. There is broad agreement that the main upper trough
passage looks to be on/around Thursday (give or take). As is
typical for the time of year, any heavy rainfall and severe
storm hazards will be more of a mesoscale challenge. High
pressure enters from the northwest to end the week delivering
lower dewpoints and cooler temperatures.

Gagan

&&

.AVIATION...
Issued 315 AM CDT Sat Jul 12 2025

Showers are gradually diminishing across southern WI this
morning, but lower MVFR/IFR stratus will remain in its wake.
Expect these lower flight conditions to continue through the
first half of the morning, but is progged to gradually
lift/break up later this morning. VFR conditions and southerly
winds expected into the afternoon. There will be another window
for a broken line of showers and thunderstorms to develop this
afternoon and evening along an approaching cold front. Main
window will be between 20z-00z today. While coverage remains
spotty, any terminal impacted by this activity will likely see a
brief window of lower ceilings and drop in visibility. Also
cannot rule out a stronger gust or two with any activity that
may develop, especially for MKE, UES, and SBM. Otherwise, the
cold front will continue to work its way across southern WI this
evening bringing lighter westerly winds overnight into Sunday.
Drier weather and lighter winds are expected for Sunday as high
pressure skirts south of the region.

Wagner

&&

.MARINE...
Issued 312 AM CDT Sat Jul 12 2025

A broad area of low pressure continues to gradually lift
northeastward across WI and Lake Michigan this morning. It
looks to eventually merge with a deeper low pressure tracking
across Ontario through the morning. Expecting to see increasing
southerly winds along with scattered thunderstorm activity
across Lake Michigan this morning/afternoon. Then a cold front
extending off the low pressure tracking across Ontario will push
across Lake Michigan later this afternoon and evening resulting
in more westerly winds tonight. Then high pressure will move
across the southern tip of Lake Michigan on Sunday, with winds
turning southerly and southwesterly as the high moves east.
Southerly flow is then expected into at least Monday, before a
front becomes stationary over the central portion of the lake
through midweek.

Wagner

&&

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

$$

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