NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 231152
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
652 AM CDT Tue Jun 23 2026

.KEY MESSAGES...

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

- On and off thunderstorms possible this weekend into early
  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 650 AM CDT Tue Jun 23 2026

No major changes to the going forecast from the 06z model
guidance. Dry and quiet weather expected through at least 9:00
PM CDT this evening. Shower and thunderstorm chances then begin
to slowly push from west to east into the region, with the
better chances (over 50%) holding off until after midnight
tonight.

Sheppard

&&

.SHORT TERM...
Issued 124 AM CDT Tue Jun 23 2026

Today through Wednesday night:

A few areas of patchy fog in river valleys this morning under
clear skies and low to calm winds. Any remaining fog will burn off
shortly after sunrise. Winds are expected to remain light and
variable throughout today, with an easterly lake breeze
developing during the afternoon hours and progressing inland
through much of southern Wisconsin through the evening. Expect
highs in the upper 70s inland, with highs in the low 70s to upper
60s near Lake Michigan and immediately inland. Cloud cover will
increase through the afternoon and evening as a developing low in
the northern Plains begins to build warm frontogenesis across
central Wisconsin. An isolated shower is possible along the
frontogenesis zone, but is not likely (~10% chance).

Overnight tonight, expect storms to develop upstream in Minnesota,
progressing southeastward through the warm frontal region into
central Wisconsin. Main hazard with these storms at this time is
expected to be lightning, as LLJ dynamics remain to the north and
MUCAPE values only increase to a few hundred J/kg. Temperatures
will remain in the upper 50s to low 60s through the overnight
hours.

Going into Wednesday, expecting showers and storms to linger
across central Wisconsin and spread into southern Wisconsin as low
pressure begins to propagate southeastward into northern
Wisconsin. The warm front from this low will finally progress
eastward through southern Wisconsin midday Wednesday, with strong
southwesterly winds developing behind it. This will allow for
destabilization across especially southwestern to south-central
Wisconsin as temperatures rise into the upper 70s to near 80
degrees. SBCAPE on mesoscale models is pushing 2000 J/kg with the
00Z runs, while globals remain modest around 1500 J/kg. With
instability and shear increasing (0-6 km shear around 45-50 kt and
0-3 km shear around 25 kt) in the afternoon hours, expecting some
storms to become severe as a final cold front sweeps through the
region late in the afternoon into the evening hours. With strong
offshore flow, severe potential exists all the way to Lake
Michigan. Main hazards at this time look to be damaging winds and
hail within stronger storms.

The cold front pushes south of the WI/IL border Wednesday night
as low pressure exits into Michigan. Expecting storms to weaken
around sunset, with drying conditions overnight. Winds may weaken
enough to allow for ground fog to develop, especially in
southwestern Wisconsin. Expect lows in the mid-50s.

MH

&&

.LONG TERM...
Issued 124 AM CDT Tue Jun 23 2026

Thursday through Tuesday:

Low pressure stalls over Michigan on Thursday, bringing a final
wave of isolated to scattered showers and storms (20-35% chances)
across southeastern to central Wisconsin. Meanwhile, low pressure
develops in the southern Plains while high pressure builds over
Ontario, bringing dry conditions to southern Wisconsin Thursday
night through Friday. Temperatures return to seasonal norms into
the weekend as low pressure deepens across the northern Plains and
brings additional warm frontogenesis to the Upper Mississippi
Valley. Precipitation chances return Saturday night into Sunday
night as well as low pressure lifts into Ontario, but models
diverge on coverage and intensity (20-40%). As low pressure lifts
farther north and high pressure builds across the Southeast U.S.
Monday into Tuesday, stiff southwesterly winds will bring rising
temperatures to southeastern Wisconsin. Potential for highs in the
upper 80s to low 90s, however, widespread cloud cover from WAA
precipitation (PoPs 20-35%) will likely modulate these
temperatures away from the 90s. Still, hot and humid conditions
are likely to start the work week.

MH

&&

.AVIATION...
Issued 645 AM CDT Tue Jun 23 2026

Dry weather and VFR conditions through today, with light and
variable winds. A localized lake-breeze circulation will develop
along the Lake MI shoreline midday, pushing inland through the
afternoon and evening (included in TAFs where applicable).
Expect predominantly easterly flow behind that lake breeze front
(northeast for the early phase of it, transitioning to due east
and eventually southeast). Some 5,000-8,000 ft diurnal cumulus
clouds might develop this afternoon; areas east of the lake-
breeze boundary may see these clear out.

Shower and thunderstorm chances expected across the region late
Tonight through Wednesday evening. Some locally stronger storms
may occur Wednesday afternoon through early evening. A light
south breeze develops tonight, veering southwest and
accelerating into Wednesday.

Sheppard

&&

.MARINE...
Issued 124 AM CDT Tue Jun 23 2026

High pressure around 30.2 inches over the Upper Midwest will bring
light and variable winds throughout 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 ahead of developing strong low pressure in
the northern Plains.

MH

&&

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

$$

Visit us at weather.gov/milwaukee

Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee