NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 221832
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
132 PM CDT Wed Jul 22 2026

.KEY MESSAGES...

- Dry & less humid through the rest of the work week. Muggy conditions
  return this weekend.

- Showers & thunderstorms return to the forecast Saturday
  evening. Rounds of storms, possibly severe, are possible into
  the middle of next week.


&&

.SHORT TERM...
Issued 132 PM CDT Wed Jul 22 2026

Rest of Today through Friday:

There were more widespread cumulus clouds and lightly stronger
winds across southern WI today than what was previously
expected, but our forecast highs remain on track at around 74
to 75 (except a degree or two cooler along the lakeshore due to
the lake breeze).

With surface high pressure over southern WI tonight, expect
efficient radiational cooling and another night with lows in
the lower 50s.

Light south-southwest winds are expected Thursday as the high
begins to exit. Inland highs will be in the upper 70s. Expect a
lake breeze to drop the afternoon temps a couple degrees near
the lakeshore.

Steadier southerly winds will develop Friday as a surface trough
approaches from the Northern Plains, but a lake breeze is still
expected. High temperatures will be around 80 with quiet weather
continuing.

Cronce

&&

.LONG TERM...
Issued 132 PM CDT Wed Jul 22 2026

Saturday through Wednesday:

A weak surface trough stemming from a broad upper low and
associated surface low crossing Ontario will sag through WI on
Saturday. This will mainly bring a wind shift from southwest to
west, but the 850-700mb warm air advection and weak surface
convergence (enhanced by the lake breeze) may help trigger a
few showers or thunderstorms in the afternoon and evening.
Saturday high temps will be in the mid 80s with dewpoints
creeping back into the 60s. It will feel warm and humid.

Sunday afternoon and night, and potentially into Monday, look to
bring some more unsettled weather into the area. Overall, there
will be another broad, warm and humid ridge over the center of
the country. This ridge should push into at least the southwest
half of WI on Sunday and bump our highs to around 90 with
dewpoints pushing 70 (very warm and humid). Meanwhile, a mid
level shortwave trough is expected to slide across the
US/Canadian border from MN to Lake Superior to Lake Ontario,
coincident with an 850mb baroclinic zone. It looks like
ingredients (moisture, instability, shear) will be in place over
at least central WI Sunday afternoon/night for the potential for
a round of severe storms. The forcing would be the nose of the
low level jet and shortwave trough. There is more uncertainty
for how far south the storms will get Sunday night.

The ridge will hang on over the central U.S. through much of the
next week. Several more shortwave troughs are expected to track
across the Upper Great Lakes from Monday through Wednesday, so
additional rounds of storms (possibly severe) are likely for
central and southern WI. Each round will depend on how the
previous day's storms panned out. This looks to be an active
weather pattern setting up for WI.

Cronce

&&

.AVIATION...
Issued 132 PM CDT Wed Jul 22 2026

VFR conditions are expected across southern WI through
Thursday, with the potential for MVFR and IFR conditions over
the Wisconsin River Valley Thursday morning if fog develops. As
a surface high pressure system moves into the region from the
Plains, winds are expected to become light and variable
overnight into Thursday, then becoming light westerly to
southwesterly in the afternoon. Diurnal cumulus cloud
development is expected to diminish this evening and return
Thursday afternoon with bases around 5 kft.

Zawlocki/Cronce

&&

.MARINE...
Issued 132 PM CDT Wed Jul 22 2026

Light and variable winds are expected tonight into Thursday as high
pressure around 30.1 inches crosses Wisconsin and southern Lake
Michigan. Look for southerly winds to develop by Friday as the
high progresses into the northeastern United States. A 29.5
inch low pressure will move quickly from the Canadian Great
Plains toward Quebec Friday through Saturday, maintaining south
to southwest winds over Lake Michigan. The low will attempt to
pull a cold front into the western Great Lakes on Saturday,
with the boundary slowly advancing south across the waters
through Saturday night, which will result in returning
thunderstorm chances. A stationary front is expected to sit
across Lake Michigan through the middle of next week, so there
will be switches between northerly and southerly winds at times.
This front will be the focus for several rounds of
thunderstorms, possibly severe.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

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