NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 030701
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
201 AM CDT Fri Jul 3 2026

.KEY MESSAGES...

- Scattered, non-severe showers & storms possible through the predawn
  hours. Flood Watch remains in effect in Sauk County through 7
  AM.

- Chances (~30-50%) for thunderstorms this afternoon & evening
  (~12-8 PM) if enough instability recovery occurs in the wake
  of morning showers/storms. A few severe storms with gusty
  winds and hail are possible.

- Additional batches of showers and storms continue late tonight through
  Sunday. Keep up with the forecast if planning to be outdoors.

- Trending quieter early next week.

&&

.SHORT TERM...
Issued 200 AM CDT Fri Jul 3 2026

Today through Tonight:

Synopsis/Mesoanalysis: Regional radar mosaics remain busy tonight
following an evening of strong to severe storms across southern
Wisconsin. Said storms laid down an elongated outflow boundary,
which currently stretches from the Chicago metro to just south of
the Des Moines, Iowa vicinity. Thanks to a southwesterly low level
jet in place regionally, ascent up & over the outflow has allowed
convection to blossom to the north/cool side of the boundary from
Iowa across northern Illinois. Some of this activity could leak
north into southern Wisconsin through the remainder of the overnight
hours, particularly to the south of I-94 and US-18. Further to the
west over the Central Plains, additional widespread convection is
ongoing over Nebraska. While these storms will remain well west of
the area through tonight, high-res forecast guidance is hinting at
an affiliated remnant shortwave/MCV crossing the region this
afternoon. Whether this feature will be able to trigger storm
development will depend on air mass recovery in the wake of predawn
showers/storms regionally, with forecast trends being monitored
through the rest of this morning. In the event storms were to form
this afternoon, a few would be capable of producing gusty straight
line winds. Additional showers and storms are possible during the
predawn hours Saturday. With clouds & areas of showers/storms around
the region, temperatures are expected to remain below heat headline
thresholds today.

Rest of the Overnight: Will be monitoring convective trends over
Iowa and northern Illinois as storms regenerate over the top of
outflow boundaries laid down by earlier evening convection. Expect
that development will continue over these regions through the
remainder of the overnight hours given a persistent southwesterly
low level jet & attendant overrunning. Whether activity manages to
propagate further north/into southern Wisconsin remains more
uncertain, as the low level air mass remains worked over in the wake
of multiple batches of convection last evening. Best convective
potential will be along/south of I-94 & US-18, where elevated
instability values remain a touch higher compared to further north.
Not expecting severe weather in the event convection makes it back
into the area, though heavy downpours would be possible. Have
maintained the existing Flood Watch over Sauk Co given antecedent
wet conditions & convective chances. If appreciable precip stays
south of the region through the rest of the overnight, watch will be
allowed to expire as scheduled at 7 AM.

This Afternoon & Evening: Forecast uncertainty increases as a
remnant shortwave/MCV from storms currently over the Missouri Basin
moves across the region. If sufficient destabilization can occur in
advance of the feature, it could help trigger scattered storm
development during the ~12-8 PM timeframe, with a few severe storms
with gusty winds and hail possible. If, however, morning convection
over Iowa/Illinois/southern Wisconsin holds better instability to
the south of the region, storm coverage would be minimal. Will thus
be monitoring trends closely, as what storms do through the morning
hours will go a long way in determining what the radar looks like
come afternoon. Will continue to provide forecast updates through
the morning.

Tonight: Will be watching for more thunderstorms during the predawn
hours as one or multiple clusters of convection move into the
Mississippi Valley from the Plains. Expect that convective
intensities will be waning as these storms approach, likely limiting
severe potential. Will continue to monitor trends and provide
updates through today.

Quigley

&&

.LONG TERM...
Issued 200 AM CDT Fri Jul 3 2026

Independence Day through Wednesday:

The upper ridge over the eastern CONUS will gradually diminish as
mid level westerlies win out as they head east of the Great Lakes
region Sunday and Monday. Unfortunately, our region will remain in a
battle zone of sorts for Independence Day into Sunday. From a large
scale pattern perspective, it is prudent to expect an convective
system or two. However the timing and details will be heavily
determined by how the mesoscale is altered by convective behavior
and remnant boundaries Friday and Friday night. At this time, from a
large scale pattern perspective, it appears the better rain chances
shift east of the area on Sunday, but this will have to be closely
monitored day to day.

Early next week, ensemble consensus is for a mid level ridge to
build over the Rockies, nudging our upper level pattern into
northwest flow. This will deliver typical July conditions with lows
in the 60s and highs in the 80s. Small ripples from time to time are
to be expected in this northwest flow pattern, though timing these
individual waves is a futile exercise. Bottom line, there will be a
good amount of dry time, and intermittent chances for showers/storms
with any ripples.

Gagan

&&

.AVIATION...
Issued 200 AM CDT Fri Jul 3 2026

VFR flight categories prevail through large portions of the period
at all fields, with SCT to BKN clouds based near FL040. Periods of
showers and storms will bring occasional categorical reductions,
with prevailing VFR returning in the wake of departed convection.
Some storms could produce gusty winds and hail.

Quigley

&&

.MARINE...
Issued 200 AM CDT Fri Jul 3 2026

High pressure around 1020 mb will remain parked over the Ohio Valley
and Appalachian Mountains into tonight. Meanwhile, a trough of low
pressure will remain over the Great Plains through tonight. A weak
low pressure area may then organize and slowly move across Wisconsin
and Lake Michigan from Saturday afternoon into Sunday, or pass
farther south across Illinois into the Ohio Valley. Modest south to
southwest winds will become lighter today. Light to modest
winds are then forecast for the weekend, but with some
uncertainty on wind direction given low confidence in the track
of the low. A stormy period is expected for central and southern
Lake Michigan through the weekend. Patchy marine fog will be
possible at times as warm and humid air flows over the
relatively cooler lake.

Quigley

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Flood Watch...WIZ056 until 7 AM Friday.

LM...None.
&&

$$

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