NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 232347
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
647 PM CDT Tue Jun 23 2026

.KEY MESSAGES...

- Chances for thunderstorms tonight through Wednesday evening. A
  Marginal Risk for severe thunderstorms develops Wednesday
  afternoon and early evening, with the main hazards damaging
  winds and hail.

- On and off thunderstorms possible this weekend into the middle
  of next week.

- Slightly below normal temps continue through Friday with a
  strong warming trend early next week, potentially nearing Heat
  Advisory criteria next Monday and Tuesday.

&&

.UPDATE...
Issued 648 PM CDT Tue Jun 23 2026

An easterly lake breeze has progressed inland to Fond du
Lac/Jefferson/Whitewater, and will likely stall within the hour.
A decaying MCS will progress southeastward late tonight and
produce generally light to moderate rain and isolated lightning
across areas north of I-94 (60-80% PoPs). The south side of the
system may produce scattered storms across areas south of I-94
late tonight, but expected to be more scattered (20-40%
coverage). Precipitation will continue into Wednesday, with a
potential break around midday.

MH

&&

.SHORT TERM...
Issued 1259 PM CDT Tue Jun 23 2026

This afternoon through Wednesday night:

Latest short term models are showing a few sprinkles possible in
the east this afternoon, largely due to low level convergence
from prevailing light southerly winds away from the lake and
easterly winds near the lake. Models soundings are fairly dry
though, so will maintain a dry forecast for now.

Moisture and warm air advection are anticipated this evening
into tonight along with gradually increasing instability.
Precipitable water values around 0.75" this morning are expected
to increase to around 1.30" tonight. Forcing and moisture
should be plenty for a round of showers and isolated to
scattered thunderstorms as a weak wave moves through late this
evening into Wednesday morning. Latest models suggest this slow
moving wave should bring precip to all of southern Wisconsin, so
will maintain the high rain chances. Marginal shear,
instability, and lapse rates suggest any storms should stay sub-
severe for this first round of precip through Wednesday morning.

A weak surface low and associated front are expected to move
through later Wednesday afternoon into the evening. Given enough
of a break after the first round of precip, scattered storms may
fire as the low and front move through. 0-6 km bulk shear will
be in the 30-40 kt range, with surface based CAPE around 1500
J/kg if sufficient recovery occurs. Some organized storm
development will thus be possible, with a few strong to severe
storms not out of the question. Hail and damaging winds still
look like the main concern for any storms that do become severe.
The main window of opportunity for stronger storms tomorrow
currently looks like 4 to 10 pm. A few showers with isolated
thunder may hang on late evening into early night as the main
trough swings through, with dry weather then likely the
remainder of the night behind the trough.

DDV

&&

.LONG TERM...
Issued 1259 PM CDT Tue Jun 23 2026

Thursday through Tuesday:

A few showers will be possible in the east tomorrow along
surface convergence due to the lake breeze and as weak cyclonic
flow aloft lingers. Not out of the question for a rumble of
thunder as well. Otherwise, skies should be partly cloudy with
highs in the 70s once again.

The upper level flow is expected to be zonal on Friday, with
upper level ridging beginning to build in from the west on
Saturday. Dry weather is expected both days under surface high
pressure. Temps will remain a bit below normal Friday, warming
back to around normal Saturday as the upper ridge builds in.

Upper level ridging will continue to strengthen across the
Midwest and Northeast United States early next week, with
increasing temperatures likely for southern Wisconsin.
Dewpoints will increase as well, with a chance for Heat Advisory
conditions Monday and Tuesday, especially if it remains dry
through this period. That said, there is a chance that storms
could move through the top of the ridge and impact southern
Wisconsin once or twice from Sat night through early next week.
Confidence is on the lower end in any potential precip timing at
this point.

DDV

&&

.AVIATION...
Issued 648 PM CDT Tue Jun 23 2026

Easterly lake breeze all the way east to FLD/UES/BUU will weaken
within the next few hours, with light and variable winds
expected for the first half of the overnight hours. Winds shift
to become southerly by Wednesday morning, then southwesterly
gusting 15-20 kt Wednesday afternoon. Winds diminish Wednesday
evening into Wednesday night.

VFR conditions expected through late tonight, with MVFR ceilings
and visibilities moving in along with steady rain and embedded
lightning late tonight into Wednesday morning. Expecting storms
to become scattered south of the I-94 corridor during the
morning hours, with precipitation ending northwest to southeast
midday. During the afternoon and evening hours, expecting an
additional round of thunderstorms to progress northwest to
southeast, also with local visibility and ceiling drops to MVFR.
These storms may become capable of producing damaging winds and
isolated large hail. Storms gradually taper off from west to
east during the late overnight hours, with conditions improving
thereafter.

MH

&&

.MARINE...
Issued 1259 PM CDT Tue Jun 23 2026

High pressure around 30.2 inches over the Upper Midwest will
bring continued light and variable winds throughout the rest of
today and tonight. Low pressure 29.9 inches developing over the
northern Plains tonight and progressing into northern Wisconsin
on Wednesday will bring southwesterly winds and thunderstorms
to the lake. Winds shift northwesterly as low pressure exits
into Lower Michigan on Thursday, with isolated thunderstorms
remaining possible. Light northerly winds expected Thursday
night, continuing through Friday. Friday night into Saturday,
expect light and variable winds under high pressure around 30.1
inches, before winds shift to become southeasterly Sunday ahead
of developing strong low pressure in the northern Plains.

DDV

&&

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

$$

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