NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 091902 CCA
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
158 PM CDT Sun Aug 9 2026

.KEY MESSAGES...

- Thunderstorm chances again this evening. There is the
  potential for an evening round. Strong to severe storms will
  be possible.

- Any storms this evening will be capable of heavy rain.
  Localized flooding will be possible, especially where storms
  repeatedly track.

- Periodic chances for showers and thunderstorms are possible
  through the first half of the week.

&&

.SHORT TERM...
Issued 200 PM CDT Sun Aug 9 2026

Tonight through Monday night:

There will be some evening storm potential but there remains
higher uncertainty given the the day time convection and
uncertainty in how its progression will affect where the
boundary sets up tonight in addition to the questions regarding
recovery. The warm front will still remain well to the north and
bring some convection to northern WI where we will be focused on
the placement of the remnant boundary from daytime storms, but
the return flow should allow for a window of destabilization. In
addition effective bulk shear should be around 40-50 kts. Thus
the environment is capable of bringing severe storms provided we
get storms. In addition, where this boundary sets up may also
very well set up a significant heavy rain scenario given PWATs
around 2 in and largely west to east propagation. Fortunately,
corfidi vectors are a bit more progressive in the latest model
runs. Wherever this sets up though we should expect heavy rain
and potential for flooding. Latest models have generally trended
things further south with development with far southeast WI
having the greatest risk for evening storms.

Outside of light pockets of rain from WAA overnight into Monday
we will carry limited precip chances as the warm front sags
south out the area tonight. Most models have the front stalling
just south of the WI/IL border with Monday afternoon and evening
activity largely staying south of the CWA though if this front
is even slightly further north that would put us in a zone of
increased storm potential. Given plenty of instability over 2000
J/kg and effective bulk shear in the 40-55kt range there will be
potential for severe storms though forcing may not be strong
enough from just the front as several CAMs struggle to produce
convection at all Monday afternoon/evening. This will be a
period to watch but chances will be limited as there are
multiple pieces of model output that limited chances for storms
generally in addition to the location of any initiation likely
being focused south. We will be mentoring forcing and potential
initiation location closely over the next 12-24 hours.

Kuroski

&&

.LONG TERM...
Issued 200 PM CDT Sun Aug 9 2026

Tuesday through Sunday:

Early Tuesday morning a shortwave will be sliding through
southern MN into southern WI and/or northern IL into the day
with an instability gradient likely set up WNW to ESE in that
same general vicinity. This will likely be elevated given the
morning timing but we cannot rule out something surface based
and given deep layer shear around 40+ kts severe storms could be
possible through the early afternoon as this feature tracks
through the region. There is naturally quite a bit of
uncertainty with this given some much activity through Monday
that may affect Tuesday potential but the setup is favorable for
strong to severe storms with heavy rain. We do get a sneak peek
at some the end of the time range of CAMs for this period and a
there are several that develop organized convection tracking for
WI/IL border so that will be something to watch.

Beyond Tuesday uncertainty increases significantly though the
pattern remains the same with ridge to the west and trough to
the east that the upper levels indicate several shortwaves
swinging through throughout the remainder of the week. In
addition, the instability gradient will likely be in the region
throughout the week with decently strong shear. Cannot rule out
strong to severe storms at various points the rest of the week

Kuroski

&&

.AVIATION...
Issued 200 PM CDT Sun Aug 9 2026

Some scattered to isolated showers possible the next few hours
with pockets of MVFR CIGS though VSBYS should stay VFR. The rest
of the afternoon should otherwise remain quiet. Into the evening
some redevelopment of storms in southeast WI will be possible
with heavy rain and lightning the primary concerns though cannot
rule out stronger storms as well. By the late evening and early
overnight hours that should end with quieter conditions
overnight into Monday weather wise. However, we expect some low
MVFR/IFR CIGS and VYBYS from fog and low stratus overnight into
Monday before it starts to clear out Monday. Additional storms
chances Monday evening/night with additional MVFR CIGS and VSBYS
possible at night as well.

Kuroski

&&

.MARINE...
Issued 200 PM CDT Sun Aug 9 2026

Winds will become light and mostly variable ahead of a sagging
front. The front will move southward down the lake into Monday,
leading to light northerly winds through the morning on Monday and
light and variable winds Monday afternoon and evening. Light and
variable winds then persist into Tuesday as high pressure of 30.0
inches remains in place north of a frontal boundary parked over
the Corn Belt. Otherwise an unsettled weather pattern has set up
over the Upper Great Lakes this week where weak waves of low
pressure will cross the region and produce rounds of thunderstorms
at times primarily a risk for the south half. The first round of
weakening storms should arrive late morning and early afternoon,
and additional storms are possible there Sunday night and beyond.

Kuroski

&&

.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