NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 021644
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1144 AM CDT Wed Sep 2 2026

.KEY MESSAGES...

- Unseasonably warm and muggy conditions continue through the
  end of the work week. Upper 90s to near 100 degree heat
  indices will be possible daily in areas experiencing ample
  sunshine, especially today.

- Occasional storm chances continue into the beginning of the
  weekend, with plenty of dry periods in between. Some storms
  could be on the stronger side.


&&

.SHORT TERM...
Issued 1144 AM CDT Wed Sep 2 2026

Tonight through Thursday night:

The hot and humid conditions continue across southern Wisconsin. A
stationary front is roughly along I-94 this afternoon which will
result in slightly cooler conditions for areas north of the
interstate. These slightly "cooler" conditions are the result of
lower dewpoint values more than anything which makes the feels like
temperatures more bearable in comparison to areas further
south. The result is dewpoints in the low to mid 60s near
central Wisconsin with dewpoints in the low 70s across far
southern Wisconsin. This means that the areas on the border line
of a heat advisory are those WI/IL border counties. Today as
already been a more bearable day in comparison to yesterday
with dewpoints well below the upper 70s to low 80s of yesterday
afternoon. This should keep conditions below the apparent
temperatures of 100 and away from heat headlines for today.
Through the rest of the work week heat index values in the 90s
are expected, but there is uncertainty on if we will be warm
enough to reach 100. Any rain/storms or cloud cover could impact
temperatures just enough to sway values a few degrees.

Given the hot and humid environment, southern Wisconsin is primed
for storms should we get any forcing or lift. The mid level WAA is
very strong which is resulting in a strong capping today and
Thursday. This will make it difficult for any storms to become sfc
based. There is a frontal boundary draped across southern
Wisconsin this afternoon that will linger in the area through
Thursday. This will provide some weak forcing for rain and
thunderstorm development. For this afternoon, there is a
noticeable lack of lift and synoptic support aloft. So its
unlikely that we will get any rain/storms until this
evening/tonight.

For Thursday, there will be a shortwave trough aloft which will help
provide lift for the CWA. The LLJ during the overnight into early
morning hours will also provide some forcing. Meso guidance suggests
that the rain and storms will likely follow a similar path to
the previous night where storms stay attached to the LLJ which
focuses across central Wisconsin. Unless an outflow starts to
move through its hard to see any rain or storms working through
the center of the CWA (low chances 10-15% but not impossible).
Across south central Wisconsin precipitation chances jump to
40-60% under the more favorable support. Given the high PWATs
and moisture as well as the 30-40kt wind shear. Organized
convection is not out of the question with the early morning
round. Its likely that the main threats will be wind with the
water loading.

For Thursday evening/night, there will be additional chances for
rain with another mid to upper level shortwave. The diurnal
instability for the day time and the presence of a that
aforementioned frontal boundary sagging south toward the state
boarder should all be more than enough for storm initiation. Rain
and storms chances in the evening will be low around 10-30% until
the frontal boundary starts to move south. Then precipitation
chances jump to 40-60%. Again with shear around 40 kts, there will
be a potential for organized convection. Strong winds will again be
the main threat, but can't rule out some small hail. Overall for
Thursday the early morning hours and overnight hours will be the
times to keep an eye on for rain/storms.

Patterson

&&

.LONG TERM...
Issued 1144 AM CDT Wed Sep 2 2026

Friday through Wednesday:

The warm and unsettled weather is expected to continue across
southern Wisconsin through the extended. With an upper level high
centered over the southern CONUS, south to southwest winds straight
out of the Gulf will remain through the extended. Therefore,
temperatures in the 80s and dewpoints in the upper 60s to 70s are
likely to continue. With that the high heat index is likely to
persist as well. With the sustained southwesterly flow, there will
be enough warm air and moisture for storms at any given time through
the extended. For Friday, there will be the combination of the LLJ
during the overnight hours with a lingering sfc boundary for day
time development. Similar to what we are seeing earlier in the week.

Once we get into the weekend the diurnal instability remains, but
there is a noticeable lack of sfc forcing. The LLJ shifts north and
west while the sfc frontal boundary sags to the south.
This will lead to more disorganized rain and storms chances. Shear
looks to weaken as well during this time which in turn limits the
potential for an pesky isolated stronger storms. Realistically it
should close the door on it, but if there is enough diurnally driven
instability then we don't want to count out any single cell pop up
thunderstorm just yet. A thunderstorm that gets tall enough or water
logged enough can always cause some downburst type winds. But that
should be very few and far between, more an exception that a rule in
the environment we should have.

Further ahead for early next week there is a signal for the ridge
aloft to weaken a bit. Meanwhile a low pressure system moving across
Canada looks to potentially clip the Great Lakes Region. From the
global deterministic models, the GFS looks to be the further south
with the low pressure system and tries to undercut the high, while
the Euro and CAN keep the low further north. This split in track
continues when looking at the cluster analysis and ensembles.
Regardless of track a cold front looks to move across the state with
this associated low. So this comes down to a timing and strength of
the front question as well. Overall just something to keep an eye on
as we head into the weekend.

Patterson

&&

.AVIATION...
Issued 1144 AM CDT Wed Sep 2 2026

VFR conditions are expected through the rest of the afternoon
and into the evening hours. Lower flight categories are not
expected to return until tonight across portions of south
central and east central Wisconsin when rain and thunderstorms
develop again. Fair weather cumulus clouds and some mid to upper
level clouds are moving east across southern wisconsin this
afternoon. Fair weather cumulus clouds will be the lowest around
3-5 kft and should be few to scattered. Winds will be light and
easterly for much of the day. Light and variable winds will be
possible at times, especially tonight.

The next chance for showers and storms will be around midnight
through early Thursday morning. The best chances (50-60%) for
storms will be for areas near central Wisconsin. Lightning and
strong winds will be a concern for any storms. Lower ceilings
around 2-4 kft and visibilities around 3-6 SM will be possible
with any storms. Thursday afternoon VFR conditions should
largely return with rain and thunderstorms expected to develop
again Thursday night. Light and variable winds Thursday morning
are expected to become predominantly east to southeast winds by
Thursday afternoon.

Patterson

&&

.MARINE...
Issued 1144 AM CDT Wed Sep 2 2026

A stationary front will remain across the Great Lakes region through
Friday. As this frontal boundary waffles north to south across the
lake from day to day, light and variable winds are expected across
the lake. Generally east to northeast winds are expected north of
the front with east to southeast winds south of the front. On and
off thunderstorms will be possible along and north of this frontal
boundary through at least Friday night.

Heading into Saturday high pressure around 30.1 inches builds over
the Hudson Bay and broad, while a low pressure of 29.6 inches moves
into the northern Great Plains. Similar to earlier week storms,
widespread severe weather isn't anticipated, though isolated
stronger storms with hail and gusty winds are possible.

Patterson

&&

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

$$

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