NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 070505
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1205 AM CDT Tue Jul 7 2026

.KEY MESSAGES...

- Patchy fog possible west of Madison overnight,especially in
  the Wisconsin River Valley.

- Shower and storm chances increase Wednesday into Thursday. Low
  chances possible Wednesday morning (15-30%) north of I-94,
  better chances (>50%) Wedensday evening into Thursday morning
  for all of southern WI.

- Cannot rule out an isolated stronger storm or two Wednesday
  evening. Also will be a potential for localized
  ponding/flooding due to increased moisture and slow moving
  nature of the system into Thursday morning.

&&

.SHORT TERM...
Issued 1201 AM CDT Tue Jul 7 2026

Today and Tonight:

Light and calm winds overnight into early morning hours will
continue as surface high pressure continues to work its way
southward across the area through the day. Could see some patchy
fog develop across portions of the Wisconsin River Valley as
temps drop through the early morning hours. Will be keeping an
eye on the line of thunderstorms trekking across MN and
northwest WI tonight as a few showers may clip the western
portions of the CWA, however, with the drier air and subsidence
from the surface high, most 00z CAMs have this activity
weakening before clipping our neck of the woods.

Otherwise, expect temps to climb into lo to mid 80s this
afternoon with mostly clear skies and plenty of sunshine. Winds
continue to remain light and given the increased thermal
gradient between inland temps and cooler Lake Michigan temps,
expect a lake breeze to develop and track inland through the
afternoon bringing cooler temps to lakeshore areas along with a
period of breezy winds. Overnight will remain mild with lows
only dipping into the low to mid 60s as the surface high
continues slide south and east of the area through early
Wednesday morning.

Wagner

&&

.LONG TERM...
Issued 1201 AM CDT Tue Jul 7 2026

Wednesday through Monday:

Will see the pattern turn a bit more active for Wednesday into
Thursday as mid-level shortwave trough is progged to traverse
across the region later Wednesday into Thursday. However, this
wave develops upstream across the northern Plains Tuesday and
looks to trigger convection across the Dakotas/MN. Some models
hint at this upstream activity lingering overnight tracking
eastward as an MCS into Wednesday morning and may clip portions
of central WI. Thus have added some low end PoP chances for
Wednesday morning for northwester portions of our CWA.

However, the better shower and storm potential for southern WI
will be later in the day Wedensday into the overnight hours as
the mid- level shortwave trough and associated mid-level
vorticity track across WI aligning with a slow moving cold front
and weak surface low feature under the right entrance region of
a sub-100 knot upper- level jet. The alignment of the forcing
paired with increasing PWATs of 1.5-2.0 inches supports 50-90%
PoPs. While timing of this activity remains in question as it
gradually trends slower and moving through more overnight into
Thursday timeframe, there is still models progging +1000 J/kg of
MUCAPE with minimal deep layer shear 20-30 kt Wednesday
evening. This would be enough to support thunderstorm
development with the initial activity and while a stronger storm
or two capable of producing small hail and localized gusty
winds cannot be rule out, the potential continue remain on the
lower side (5% chance per SPC convective outlook).

Overnight Wednesday will see the instability diminish, but slow
moving cold front and moisture is expected to persist, thus PoP
chances continue through Thursday morning. Given the moist
environment and slow moving nature of this activity, would not
be surprised to see some of the showers move over the same areas
for a period of time, which may lead to localized
ponding/flooding, especially if higher rain rates of +1"/hr
materializes, especially with any taller convection. But the
GEFS and EPS members probs of greater than 1" remain on the
lower side (<20%). Nevertheless, potential for heavy rainfall
will be there through Thursday morning and will have a better
idea as the CAMs come more into frame.

Then looking to see off and shower chances continue into
Thursday afternoon as the cold front sags through the area. Some
models prog additional development along the slow moving
boundary Thursday afternoon as an additional mid-level feature
tracks across the region. However, continue to see a deeper
shortwave trough take shape across the Central Plains track
into IA/IL/IN through the day Thursday, which may end up pulling
the cold front through faster than current forecast.

Otherwise, end of the week may start off drier as northwesterly
flow sets up across the region, but models disagree on upper-
level wave passages timing and strength. The 00z GFS is most
aggressive and faster of the models trekking a trough through
the area Friday which could bring additional shower/storm
chances, while the ECMWF is not as bullish and favors high
pressure settling across the area into the weekend.

Wagner

&&

.AVIATION...
Issued 1201 AM CDT Tue Jul 7 2026

Outside of some patchy fog west of MSN, mainly expecting VFR
conditions to prevail through the period with light and variable
winds through the day as high pressure moves overhead. Given
light flow and temp difference between land and Lake Michigan,
expecting a lake breeze to develop late morning/early afternoon
and push inland through the afternoon bringing breezy east-
southeasterly wind shift to the terminals near the lakeshore.
Then light and variable winds return overnight as high pressure
slide south and east of the area.

Wagner

&&

.MARINE...
Issued 1201 AM CDT Tue Jul 7 2026

High pressure continues to influence the pattern over Lake
Michigan today with north to northeast winds gradually becoming
light and variable as the high pressure moves over southern WI.
Then gradually see southwest winds increase into Wednesday
becoming gusty as weak low pressure and an accompanying cold
front slides in from the Northern Plains. Cold front will slowly
drag southward through the day Thursday with northerly winds
developing behind it. Then could see high pressure build into
the the Upper Great Lakes Region through the end of the week and
into the weekend.

Wagner

&&

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

$$

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