NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 051205
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
705 AM CDT Fri Jun 5 2026

.KEY MESSAGES...

- Increasing humidity and thunderstorm chances for late tonight
  through Saturday. A 1 out of 5 (marginal) risk for severe
  storms is forecast Friday. Hail, gusty winds, and lightning
  will be the main hazards.

- Trending less likely for storm chances through the rest of the
  weekend as a cold front pushes through and a Hudson Bay high
  pressure returns to the Upper Great Lakes.

- Next round of rain is expected early next week.

- Hot and humid conditions expected mid to end of next week with
  some potential for Heat Advisory conditions late next week.

&&

.UPDATE...
Issued 705 AM CDT Fri Jun 5 2026

Showers with some thunderstorms rolled into southern WI from
eastern IA this morning. The wind is light, even with the
heavier showers/storms. Cloud-to-ground lighting is our main
threat this morning, especially toward the IL border. Many
areas along and south of I-94 are getting beneficial rainfall.

The current area of showers/storms will continue to expand/shift
northeast through late morning. There is another area in
northeast MO, but this should track through northern IL.

While additional showers/storms could develop this afternoon
once this cluster exits, they would be isolated. We are still
watching for storms to roll in from central WI during the
evening.

Cronce

&&

.SHORT TERM...
Issued 1139 PM CDT Thu Jun 4 2026

Current Overnight through Friday Night:

A broken line of showers and a few rumbles of thunder have tried
to work into the area this evening but have largely been stymied
by very dry low level air. However, with time, the low levels
should begin to moisten as a shortwave trough aloft pushes east
into our area this morning and an 850mb moist advection axis
leans over into the state this morning. Rain and a few rumbles
of thunder will then linger over the area from 3AM through Noon
as the shortwave passes and the moisture axis slowly translates
eastward.

A lull is expected during the afternoon as subsidence occurs on
the backside of the shortwave, but a second shortwave over MN is
expected to kick off thunderstorm activity over northern WI
Friday afternoon. This storm activity should then track
southeast into our area Friday evening between 6PM and 10PM.
Provided the skies clear in the subsidence lull we'll have
behind the morning rain, moderate instability from 1800 to 2500
J/kg should build over southern WI ahead of the approaching
broken line of storms. Mid level lapse rates may approach 7 C/km
with effective shear of 30 knots, supporting sufficient storm
organization for some gusty winds and hail with the evening
storms.

These storms should then largely weaken after sunset as they
travel southward, growing more scattered with time, although a
few weaker pop-up storms may linger overnight Friday into early
Saturday morning.

CMiller

&&

.LONG TERM...
Issued 1203 AM CDT Thu Jun 4 2026

Saturday through Thursday:

Outflow from Friday's storms is expected to push a cold front
through the region Saturday morning. The front is then expected
to set up south of the area over IL, while high pressure slowly
builds into the region through the rest of Saturday. With the
front south of the state, rain chances are looking less likely
Saturday. High pressure continues to build Sunday, keeping
conditions dry. The familiar easterly wind pattern that plagued
us for most of May will briefly return, leading to cooler
conditions by the lake with highs in the 60s and 70s, while
highs will be in the low to mid 80s far inland. High pressure
will then begin to retreat east on Monday, allowing for
thunderstorm chances (50 to 80%) to return Monday afternoon and
evening.

A strong ridge is then expected to build over the upper midwest
mid to late next week, allowing a hot and humid air mass build
over the region. The NBM projects highs in the 90s by next
Wednesday and Thursday amid dewpoints in the low to mid 70s,
which would cause heat indices between 100 and 105. Model trends will
have to be monitored for potential heat headlines. Along with
the heat, global deterministic models depict a more summer-like
pattern, with nebulous chances for thunderstorms at times from
mid to late next week given the ample instability.

CMiller

&&

.AVIATION...
Issued 705 AM CDT Fri Jun 5 2026

Showers with some thunderstorms rolled into southern WI from
eastern IA this morning. The wind is light, even with the
heavier showers/storms. Cloud-to-ground lighting is our main
threat this morning, especially toward the IL border. Visibility
has dropped to 2 miles in brief heavy rain at a few locations
this morning.

The current area of showers/storms will continue to expand/shift
northeast through late morning. There is another area in
northeast MO, but this should track through northern IL.

While additional showers/storms could develop this afternoon
once this cluster exits, they would be isolated. We are still
watching for storms to roll in from central WI during the
evening.

The main question for mid morning through mid afternoon is the
ceiling heights. There are many observations upstream in
northern IA that are sitting at 400 ft. With daylight and some
subsidence behind this morning system, thinking the LIFR
conditions would be brief and the threat for them would diminish
this afternoon.

Cronce

&&

.MARINE...
Issued 705 AM CDT Fri Jun 5 2026

Low pressure over the Central Plains will connect with another
low over southwest Ontario. The Canadian low will track across
the northern Great Lakes today, bringing prevailing
southwesterly winds to Lake Michigan along with shower and
thunderstorm chances ahead of a cold front. Then expect the cold
front to push through the region this evening into Saturday,
bringing additional shower and thunderstorm chances along with a
more northwest to westerly wind shift behind it into Saturday.
Then winds weaken and become more variable as high pressure
around 30.0 inches builds across the region later Saturday into
Sunday. Looking ahead, the start of next week will bring an
additional low pressure system to develop over the Plains and
bring a return of southerly winds to the Upper Great Lakes.

Cronce

&&

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

$$

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