NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 080103
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
803 PM CDT Fri Aug 7 2026

.KEY MESSAGES...

- Storms may roll through southern WI late Saturday night
  through Sunday night into mid-week.

&&

.UPDATE...
Issued 804 PM CDT Fri Aug 7 2026

The last of the rain and storms are starting to peter out here
this evening. Isolated pockets of light to moderate rain will
remain possible across far southeastern Wisconsin over the next
hour or so until the last of the rain ends. The threat of any
MCS type system to move through has largely ended here which is
to be expected with the rain we have already gotten. What
instability we did have has been tapped a bit and with the
lacking shear all that remains is low chances (20% or less) for
a pop up shower prior to midnight. Otherwise largely quiet
weather is expected until Saturday night into Sunday.

Patterson

&&

.SHORT TERM...
Issued 1200 PM CDT Fri Aug 7 2026

Tonight through Sunday:

A cold front is expected to approach the region from the west
late this afternoon pushing through during the evening. Some
storms should be expected along and ahead of the front well to
our west this afternoon, However, as the front slides east most
of the CAMs have really grabbed to the idea of a storm cluster
possibly developing into an MCS over far southern MN and
northern IA this afternoon. The trend is generally for this to
move due southeast and likely miss southern WI altogether with
the exception of some blowoff rain showers on the northeast side
of the system. While we cannot rule out this clipping parts of
our southwest CWA the trends do not favor this especially when
considering the northwest winds and the better CAPE gradient
setting up NW to SE in IA. This will be something to monitor
into the afternoon but this have trended fairly quiet for this
evening. If development of an MCS starts later and/or further
east the MCS track may shift over southern WI and the shear and
instability will be enough to bring some mild severe concerns.
This is the primary concern with this. Some lingering overnight
shower/weak storm potential will persist overnight but CAMs
have nixed a lot of that potential with the latest runs.

Saturday looks likely to stay largely quiet as the frontal
passage should usher in weak high pressure through the day and
evening though this will be short lived. In addition, it looks
likely to be quiet aloft as well for this period so a quiet
Saturday looks likely. However, late Saturday night through
Sunday looks a bit more active as a shortwave looks to pull
through with some morning LLJ nudging into southern WI (strong
WAA) with a warm front in play across the western Great Lakes.
While this timing does not scream severe, if we can manage
enough instability the shear should increase enough into the day
Sunday with the LLJ that should bring some severe concerns. The
real question is in the timing of storms. If things hold off
long enough to get some daytime heating before storms the storms
we see could easily become strong to severe with deep layer
shear increasing to 40-55kts.

Strong to severe storms may remain a concern through the rest
of the day though a lot more uncertainty exists in hold the rest
of the day will play out but the environment will maintain
favorable conditions but the location of the forcing may shift a
bit. Models do favor the warm front laying over southern WI
later Sunday. In addition to a potential severe risk with
strong deep layer shear and likely a continuous feed of moisture
from the LLJ there is an increasing concern that if that warm
front lays over southern WI for a prolonged period of time
(may persist into Monday) there will be a flash flooding risk.
PWATs around 2 inches, west to east forward propagating corfidi
vectors with light to variable corfidi vectors favors both back
building to some degree and most certainly training storms. The
combination of these factors is suggestive of repeated waves of
heavy rain and may pose an increasing flash flooding risk.
However, uncertainty remains on exactly where this will set up
and whether the front is progressive at all or if it becomes
stationary. If it is at least somewhat progressive it may yield
some flooding and heavy rain concerns but likely less impact
overall.

Kuroski

&&

.LONG TERM...
Issued 1215 PM CDT Fri Aug 7 2026

Sunday night through Friday:

Additional rounds of storms will be possible Sunday night into
the middle of next week as moisture lingers and a couple more
shortwaves move through. Shear looks plentiful through at least
Monday to keep an eye on the severe storm potential. The strength
of the storms for southern Wisconsin will likely in part depend on
the timing, as any overnight/early morning storms would likely be
weaker than afternoon/evening storms. Additionally, precipitable
water values of 1.5-2.0" the first half of next week could lead to
a heavy rain potential, especially the southern Wisconsin sees
repeated rounds of storms. Timing of individual rounds of storms
remains uncertain, but this does look like a potentially active
stretch given the door will be open to shortwaves while deeper
moisture and instability remain across southern Wisconsin.
Temperatures will likely remain within a couple degrees of normal
through this period.

DDV

&&

.AVIATION...
Issued 804 PM CDT Fri Aug 7 2026

VFR to IFR conditions are expected through the period.
Predominately VFR to MVFR conditions are expected. Rain and a
few thunderstorms are moving southeast through far southern
Wisconsin this evening. Ceilings with the storms are around 3-4
kft with visibilities around 4-6 SM with the rain. This will be
a fairly narrow area of rain/storms that will clip southeastern
terminals, mainly BUU, ENW, and RAC. Mid level clouds around
6-8 kft will linger into tonight clearing from west to east
during the early predawn hours. There will be a small chance for
fog to develop mainly for areas west of Madison once skies
clear. This will be the chance for MVFR to IFR visibilities
around 2-4SM. Confidence is low that any fog will develop at MSN
or other low lying areas to the east due to the cloud cover
still lingering around. Otherwise, VFR conditions are then
expected through the rest of the period. Heading into late
Saturday night rain and storms are expected to return (20-40%
chances).

Light southwest winds this evening will gradually become
westerly after dark. Light northwest winds are expected Saturday
with southwest to light and variable winds Saturday night.

Patterson

&&

.MARINE...
Issued 1200 PM CDT Fri Aug 7 2026

Low pressure of 29.8 inches over Lake Superior along a front
will swing through tonight across the lake. Scattered showers
and storms are possible tonight as this cold front crosses Lake
Michigan. West to northwest winds behind the front early
Saturday will quickly return to southerly by Saturday evening
ahead of the next approaching low pressure system. An unsettled
weather pattern will set up over the Upper Great Lakes next week
where weak waves of low pressure will cross the region and
produce rounds of thunderstorms at times.

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