092
FXUS63 KMKX 240946
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
446 AM CDT Tue Jun 24 2025

.KEY MESSAGES...

- Cooler today with highs near 80, but still remaining muggy
  with dew points near 70.

- Scattered thunderstorms will be possible today, with a
  marginal (1 out of 5) risk for severe weather. Any strong
  storms today will feature gusty winds and heavy downpours.

- Multiple rounds of thunderstorms and a level 2 out of 4 risk
  for excessive rainfall will be present Tuesday through
  Thursday, as the surface front stalls overhead.


&&

.SHORT TERM...
Issued 407 AM CDT Tue Jun 24 2025

Today through Wednesday:

A nebulous frontal boundary will slowly sink south through
today. This front, coupled with low-amplitude wiggles in the
500mb flow, will drive scattered shower and thunderstorm
activity through today. It`s not expected to be a washout given
the somewhat nebulous forcing, but sct`d thunderstorm coverage
may peak with daytime heating this afternoon. Soundings show
skinny CAPE profiles with around 1500 J/kg of SBCAPE this
afternoon. Freezing levels and weak lapse rates will limit hail,
but some downburst potential does exist with any collapsing
storms, as DCAPE will be around 800 J/kg, surface Tdds will be
around 10 to 13 degrees, and effective shear of 25 to 30 knots
will only support marginal storm organization. Heavy downpours
still appear possible with storms today, as PWATS will still be
high at around 1.75 to 2 inches.

While it will be cooler today with highs near 80, dew points
will remain around 70, meaning higher relative humidity values
(even higher than the past few afternoons). This may make it
feel downright muggy today. Linger cloud cover will aid in this
mugginess, as dewpoints won`t mix out effectively.

The front is expected to pass this evening, bringing northeast
winds off of the lake. This will cool overnight lows into the
60s, with dew points in the 50s and low 60s. Be sure to open
those windows and enjoy the reprieve.

Wednesday, models depict a northward surge of the stationary
front as a warm front over Iowa. This warm advection may kick
off some showers and thunderstorms over Iowa Wednesday morning
that would then translate east, reinvigorate over central WI
during the afternoon, and then sag southeast into Wednesday
evening. Still a bit too early to pin down this evolution, given
some disagreement among the CAMs, but if this trend holds, our
next best chance to see another more widespread round of
thunderstorms in southern WI would be Wednesday evening.

CMiller

&&

.LONG TERM...
Issued 407 AM CDT Tue Jun 24 2025

Wednesday night through Monday:

Models are generally showing the surface boundary remaining near
or over the area Wednesday night into Thursday night, before low
pressure with the front shifts through and out of the area by
later Thursday night or Friday. The 500 mb ridge generally
flattens out during this period and remains relatively zonal
through the week, per cluster analysis. The southwesterly-
oriented low level jet should feed more moisture and upward
vertical motion into the area at times Wednesday night into
Thursday night. There may be some divergence from the right
entrance region of a jet streak moving over the region as well.

Thus, kept NBM PoPs as is through Friday, which are generally in
the 40 to 80 percent range with these features hanging out near
or over the area at times. The best probabilities from the
ensembles for one inch or more of rainfall in a 24 hour period
are generally over southwest to central Wisconsin. The EPS and
GEFS are generally showing at least 50 percent chances for at
least 0.50 inches of rainfall or more in a 24 hour period in the
northwestern half of the area. So, some uncertainty if the
heaviest rainfall would occur in or to the northwest of the
forecast area.

Still, given the boundary-parallel flow in the deep layer bulk
shear vectors, could see heavy rainfall occur with storms moving
over the same areas Wednesday night into Thursday night or
Friday. These storms would be feeding off of very moist air, with
precipitable water values around or over 2.00 inches at times.

Also, some strong to potentially severe storms may occur as well,
with bulk shear in the 25 to 35 knot plus range. Temperatures
will be more uncertain, depending on where the front sets up
through the period, and any clouds with the showers and storms
lingering. For now, expecting warm and humid conditions with highs
in the 70s north of the front and 80s to the south.

Trends over next weekend into Monday remain more uncertain, with
the potential for more rounds of showers and storms with passing
low pressure systems per ensemble member trends. Will keep NBM
PoPs (20 to 50 percent) as is in this period for now. Temperature
trends in the ensembles try to indicate warmer highs well into
the 80s during this period.

Wood

&&

.AVIATION...
Issued 415 AM CDT Tue Jun 24 2025

Scattered VFR cloud cover this morning will give way to MVFR
ceilings as a front sags south through this morning. MVFR
ceilings are then anticipated to hang around for much of the
day, with scattered thunderstorms possible at times through the
day and into tonight. Winds will be light and variable through
much of the day as the front slowly moves south. Northeast winds
are expected by this evening after the front moves south into
northern Illinois.

CMiller

&&

.MARINE...
Issued 407 AM CDT Tue Jun 24 2025

A cold front will gradually stall across the southern end of Lake
Michigan this morning. Scattered showers will linger through the
early morning hours, mainly over the middle third of the lake.

The front is expected to stick around through Thursday, waffling
back and forth from north to south over the southern third of the
lake. As a result, winds will be modest, and generally northerly
to northeasterly throughout the week. South winds may return on
Thursday over the southern portions of the lake, as the front
briefly lifts north ahead of approaching low pressure. With the
presence of the front, multiple rounds of showers and
thunderstorms are expected at times.

CMiller

&&

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

$$

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