NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 010621
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
121 AM CDT Sat Aug 1 2026

.KEY MESSAGES...

- Additional rainfall of 1-1.5 inches is expected from Lake
  Michigan counties southwestward through the WI/IL border, with
  0.5-1 inch expected elsewhere. Rates up to 0.75"/hr will
  continue through daybreak, with light to moderate rain at
  0.2-0.5"/hr north of I-94. Rain will taper off this afternoon.

- Ponding of low-lying areas and minor flooding remains a
  possibility, especially for urban areas that see several
  inches of rainfall in short period of time, but flash flooding
  is not expected given the lower rainfall rates and dry
  antecedent soil conditions.

- Breezy onshore winds will lead to high waves and dangerous
  currents at Lake Michigan beaches this weekend. A Beach
  Hazards Statement is in effect early this morning into Sunday
  night for all Lake Michigan beaches.

- Next chances for thunderstorms Wednesday through Thursday.

&&

.SHORT TERM...
Issued 121 AM CDT Sat Aug 1 2026

Today through Sunday night:

Waves will build greater than 4 ft across all Lake Michigan
beaches early this morning, with a high swim risk expected
throughout today and Sunday. Waves may build as high as 8 ft in
some areas. Stay out of the water and away from dangerous areas
like piers and breakwalls!

A band of storms with rates around 0.75"/hr will continue across
areas along and south of I-94 through this morning within a
baroclinic zone, while steady light to moderate rainfall
(0.20-0.50"/hr) continues north of I-94. Areas that see repeated
rounds of storms may see localized flooding concerns, especially
near the core of the low pressure system along the WI/IL border
(maximized convergence). Storm chances will diminish mid- morning
as low pressure pivots into central Illinois and instability
exits to the south. Rain will begin to taper off from northwest to
southeast midday onward. Areas that clear earliest may reach the
upper 70s, with the majority of southern Wisconsin remaining in
the low 70s under cloud cover. Expect gusty northeasterly winds
around 25 to 30 mph.

Additional rainfall of 1-1.5 inches is expected along Lake
Michigan to the WI/IL border and of 0.5-1 inch elsewhere. During
the afternoon hours, a weak complex of thunderstorms may develop
(15-30%) within the drying airmass in the wrap-around
precipitation region, progressing southwestward through central
Wisconsin. No severe weather is expected with this activity, with
lightning the main threat as 500 J/kg of surface based CAPE builds
in. Storms exit shortly before sunset.

Mainly dry conditions are expected tonight through Sunday morning,
with isolated showers possible along the Lake Michigan shoreline
(15-25% chances) in the wrap-around precipitation region.
Overnight lows in the low 60s are expected. Northeasterly winds
will diminish in central to southwestern Wisconsin, gusting only
around 10-15 mph. Southeastern Wisconsin will continue to see
gusts of 20-25 mph through the overnight hours. Winds will
increase again into Sunday as low pressure lifts northward into
northern Indiana, but will focus mostly on southeastern Wisconsin
with gusts 20-30 mph expected. Highs in the low 70s are expected
near Lake Michigan on Sunday, with highs in the upper 70s
elsewhere.

Skies clear and winds gradually diminish Sunday evening through
Sunday night as low pressure continues to lift northeastward
through Ohio. Expect lows in the mid 50s to low 60s.

MH

&&

.LONG TERM...
Issued 121 AM CDT Sat Aug 1 2026

Monday through Saturday:

High pressure builds in Monday and lingers through Tuesday, with
light winds and highs in the upper 70s to low 80s. Low pressure
develops in the Plains Tuesday, phasing with a shortwave moving
through northern portions of the Upper Midwest. This will lead to
chances for thunderstorms late Tuesday night into Wednesday
(20-40%). Timing of these storms will determine impacts, with
less instability to work with if storms develop during the
overnight hours. Bulk shear values remain quite weak (10-20 kt)
through Wednesday, with low pressure ejecting eastward into
Wednesday night and bringing higher shear values (40-50 kt)
Wednesday night into Thursday. This will lead to better chances
for severe weather, but timing and upper ridging may prevent
thunderstorms from impacting southern Wisconsin directly. Model
uncertainty leads to PoPs of 15-25% through this period. Thursday
into Friday, low pressure propagates eastward, with high pressure
building back in from Canada, allowing for drier conditions and
increasing temperatures (mid to upper 80s) into next weekend.

MH

&&

.AVIATION...
Issued 121 AM CDT Sat Aug 1 2026

Ceilings will continue to drop to IFR through this morning as low
pressure slides through central Iowa into northern Illinois.
Periods of higher ceilings are possible in between rounds of
rainfall, but are expected to be short lived (generally less than
1 hour increments). Ceilings will improve as rainfall moves
out midday into the afternoon hours, but will remain between 1500
and 2500 ft throughout the day. Overnight tonight, clouds will
build back down to ~1500 ft as plenty of moisture remains in the
low levels.

East-northeasterly winds this morning will become northeasterly by
mid-morning. Expect gusts to 25 kt consistently across all of
southern Wisconsin through much of the day, diminishing to 10-15
kt across southwestern to south-central overnight, but remaining
gusty around 20 kt in southeastern Wisconsin.

MH

&&

.MARINE...
Issued 121 AM CDT Sat Aug 1 2026

Low pressure around 29.6 inches will slowly progress from
southeastern Iowa through northern Illinois today, allowing winds
to slowly shift from eastward to northeastward by tonight. Expect
gusts around 30 kt in the southern half of the lake. An isolated
gale cannot be ruled out. The low will gradually move east
through the Ohio Valley through Sunday night, turning winds to
northerly and bringing 30 kt wind gusts again Sunday afternoon.
Isolated gales become possible once again Sunday afternoon. Winds
will gradually diminish through Sunday night. A Small Craft
Advisory is in effect from early this morning into Sunday night
for high winds and waves. High pressure around 30.0 inches then
builds into the eastern Great Lakes Monday, lingering through
Tuesday night. Winds remain light and variable through this
time. Low pressure develops in the central Plains Tuesday night,
bringing a return to thunderstorm potential. With low pressure
remaining well to the south, light and variable winds are
expected to continue through the end of the week.

MH

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066-WIZ071-WIZ072
     until 1 AM Monday.

LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 1 AM
     Monday.

&&

$$

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