NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 210359
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1059 PM CDT Thu Aug 20 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms (30 to 50 percent
  chances) with passing cold front mainly Friday afternoon and
  evening. Gusty winds and small hail may occur.

- Small chances (20 to 40 percent) for a shower or storm
  Saturday afternoon for portions of east central and southeast
  Wisconsin.

&&

.SHORT TERM...
Issued 1100 PM CDT Thu Aug 20 2026

Tonight through Saturday night:

Tonight should remain largely quiet outside of a few light
showers nudging into the region but despite some PVA pushing
through and low level WAA the low level moisture may be too dry
initially to bring showers to the ground. Around daybreak
Friday we expect some low level moisture to allow for precip
chances to increase for a brief period in the morning. The
forcing appears to be largely focused along the shortwave with
supplementary WAA and better moisture but CAMs do not seem to
favor widespread showers in the morning with better chances
focused further west closer to the surface front. As the front
pushes east moisture seems to improve into Friday afternoon and
evening. CAMs seem to favor some development of convection
Friday late afternoon on the western half of the CWA with a
secondary development potential into the early evening closer to
the lake. Given higher instability (>2000 J/kg) and enough
shear (30-35kts) we should see a stronger storm or two for a
brief period but the lack of better shear should limit the
potential to just a few storms at most with the primary concerns
being 1 inch hail and brief damaging winds.

Quieter conditions overnight Friday into Saturday morning as the
surface low pushes out. However, Saturday late morning and
afternoon we will likely see a backdoor cold front combined with
lake breeze convergence zone in the nearshore region bring
additional precip chances for eastern portions of the CWA. There
is some uncertainty for this primarily with respect to low to
mid level moisture and how widespread it will be but some
showers and perhaps a few storms will be possible with this. If
we can manage a few storms we could see some become strong
given a decent amount of deep layer shear though this differs
significantly between the CAMs and synoptic scale models so we
will have to monitor those conditions through Friday. This will
be worth monitoring Saturday afternoon given some potentially sneaky
conditions. Chances will rapidly decrease Saturday evening as
we lose instability and forcing pushes out.

Kuroski

&&

.LONG TERM...
Issued 1100 PM CDT Thu Aug 20 2026

Sunday through Friday:

Sunday and Monday will feature high pressure building into the
region keeping things dry through Monday. Things have trended
overall drier into Tuesday with the high pressure lingering a
bit longer with Tuesday night Wednesday becoming our next best
chance for showers and storms as and 850mb front and upper level
shortwave swing through with some WAA. Still some uncertainty
in track and timing but models generally agree on this pushing
through bringing precip with likely some storms as well. In
addition, deep layer shear appears to be strong in the 40-50kt
range which would bring some severe risk if the timing of storms
is into the evening.

After Wednesday, uncertainty increases quite a bit though in
general higher pressure seems to be pushing in with drier
conditions overall more likely.

Kuroski

&&

.AVIATION...
Issued 1100 PM CDT Thu Aug 20 2026

Quiet in large part tonight with VFR conditions generally
expected outside of a few showers potentially reducing VSBYs for
a brief period. Into Friday morning precipitation chances will
increase to the west with uncertainty as to where precipitation
with be for any period. Seems like a midday lull is expected in
precip with increased chances into the mid to late afternoon and
into the early evening. Storms chances are more likely in the
afternoon further west with increased chances further east into
the evening but continued uncertainty in location.

Kuroski

&&

.MARINE...
Issued 1100 PM CDT Thu Aug 20 2026

High pressure exits to the southeast tonight with south to
southwest winds developing. Theses winds will increase for
Friday, along with shower and thunderstorm chances, as low
pressure around 29.8 inches moves across the region and drags a
cold front through Lake Michigan. Gusty winds will then shift to
the northwest later Friday night into Saturday after the front
exits. Another high pressure system around 30.2 inches is expected
to build into the region later this weekend, which may maintain
gusty northerly winds as it moves in.

Kuroski

&&

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

$$

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