NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 151101 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
601 AM CDT Mon Jun 15 2026

.KEY MESSAGES...

- Showers (60-90 percent chance) and scattered thunderstorms on
  Tuesday. Small hail expected with the thunderstorms.

- Widespread showers (80-90 percent chance) and scattered
  thunderstorms Wednesday and Wednesday night. Heavy rain and a
  conditional threat for severe thunderstorms is forecast.

- Next chances for thunderstorms develop Saturday and Sunday.

&&

.UPDATE...
Issued 601 AM CDT Mon Jun 15 2026

High clouds across the eastern half of the forecast area early
this morning will continue to depart to the east, leaving
mostly clear skies across southern Wisconsin through at least
mid-morning. Mid to high level clouds will then push in from the
northwest by the afternoon hours ahead of an approaching
shortwave. In all, the forecast looks on track through the
upcoming day, with high temperatures warming back into the mid
70s.

DDV

&&

.SHORT TERM...
Issued 1037 PM CDT Sun Jun 14 2026

Tonight through Wednesday night:

Scattered cirrus clouds are expected to move across srn WI
during the overnight as the shortwave trough over ern SD and NE
tracks to north central IL by 12Z Mon. At the surface, calm
winds will become lgt wswly as a weak sfc ridge shifts south and
a west to east sfc trough moves swd across nrn Ontario. Good
radiational cooling conditions in an already cool airmass will
support low temps in the upper 40s inland from the lake.

The next upstream shortwave trough will track into the ern
Dakotas on Mon, then amplify as it moves to se MN by 12Z Tue.
The west to east sfc trough over Ontario will move to nw WI and
Lake Superior during this time.

Partly cloudy skies and weak warm advection on Mon should boost
temps into the middle 70s. By late Mon nt, a swly low level jet
around 35 kt and associated warm, moist advection will develop
into srn WI ahead of the amplifying upper wave. Rain chances
will increase to 20-40 percent, including chances for thunderstorms
as the Showalter Index falls to -1C. More widespread showers and
scattered thunderstorms will then develop on Tue as the low
level jet and warm, moist advection overspreads the area and is
quickly followed by the shortwave trough and cold frontal
passage. The 998 mb sfc low will be tracking from nw WI to nrn
Lake MI during this time. There is uncertainty with the timing
of the cold front of late morning into the early afternoon
versus just an afternoon passage. Either way believe showers and
clouds will keep temps down a bit, although tall, skinny CAPE
of 500-1000 J/KG could be achieved. Given low freezing levels
around 8 kft, any thunderstorms would likely have small hail
with just very low probabilities for large hail at this time. A
few showers will linger into Tue evening and briefly be followed
by a weak ridge of high pressure.

A positive tilt shortwave trough will then move across the nrn
Great Plains to srn WI Wed-Wed nt, with the sfc low to track
anywhere from central WI to nrn IL. A strong low to mid level
baroclinic zone will set up over srn WI with warm, moist advection
and frontogenesis producing widespread showers and storms.
PWATs will climb to 1.5 inches toward the IL border. Elevated
severe storms and heavy rainfall will be possible.

Gehring

&&

.LONG TERM...
Issued 1037 PM CDT Sun Jun 14 2026

Thursday through Sunday:

Cold advection will prevail on Thursday in the wake of low
pressure. Another shortwave trough will pass and maintain 20-30
percent chances for showers. Weak shortwave troughs will then
continue to bring small chances for showers and possibly storms,
more so for the weekend. Temps will remain a bit on the cool
side.

Gehring

&&

.AVIATION...
Issued 601 AM CDT Mon Jun 15 2026

Quiet weather is expected through at least the evening today,
with periods of mid to high level clouds moving through ahead of
an approaching trough. There will be a chance for showers the
second half of tonight into Tuesday morning, with a chance for
thunderstorms as well by Tue afternoon. Light westerly winds
this morning will pick up a little for the afternoon hours,
becoming southwest tonight into Tuesday as the trough continues
to approach.

DDV

&&

.MARINE...
Issued 1037 PM CDT Sun Jun 14 2026

Northwest winds will gradually diminish this evening, becoming
west to southwesterly over all of the lake late tonight, as a weak
wave of low pressure moves south across Ontario and high pressure
extends across the central portion of the country. Low pressure
is then expected to deepen to 29.5 inches over northern Wisconsin
on Tuesday, then move across northern Lake Michigan into the
early evening. This will bring breezy southerly winds to the lake
on Tuesday shifting west to northwest after the low passes.
Numerous showers and scattered thunderstorms are forecast over
central and southern Lake Michigan on Tuesday.

On Wednesday, low pressure around area 29.2 inches will move into
the Upper Mississippi River Valley from the Great Plains. This
will bring breezy southeasterly winds to central and southern
Lake Michigan Wednesday afternoon and evening, with the low to
then move across central Lake Michigan Wednesday night. As low
exits into Thursday morning, expect winds to become northwesterly
and remain gusty across all open waters into Thursday afternoon,
before gradually diminishing. Widespread rain and scattered
thunderstorms are forecast Wednesday and Wednesday night.

Gehring

&&

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

$$

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