NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 281208
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
708 AM CDT Sun Jun 28 2026

.KEY MESSAGES...

- Expecting hot and humid conditions through much of this week
  leading to dangerous heat index values and associated risks,
  such as heat exhaustion and heat stroke. Heat headlines are
  expected for much of the week. An Extreme Heat Watch is in
  effect Monday into Monday night.

- Chances for storms this morning west of the Kettle Moraine,
  with additional storm development tonight across areas
  northeast of the I-90/I-94 corridor.

- Moderate to high swim risk will develop late tonight through
  Monday for building waves in Ozaukee and Sheboygan Lake
  Michigan beaches. A Beach Hazards Statement may be needed.

- Chances for showers and storms increase a bit for mid to late
  week.

&&

.UPDATE...
Issued 708 AM CDT Sun Jun 28 2026

MCS currently over south-central Wisconsin is continuing to
maintain intensity. Still anticipating developing EML over
Wisconsin to prevent strong storms, but cannot rule out rain and
storms across southwestern to south-central midday onward with
the main hazard expected to be lightning and an outside chance
of remaining damaging winds. Overnight 00Z and 06Z meso models
have continued to develop scattered thunderstorms along a warm
front draped across central Wisconsin, bringing additional
lightning and potential for elevated storms bringing hail. If
LLJ dynamics can fire enough storms in central Wisconsin, a wind
threat also becomes possible. Overnight tonight, an elevated
swim risk also develops for Lake Michigan beaches in Ozaukee and
Sheboygan Counties. Stay out of the water and away from
dangerous areas like piers and breakwalls!

MH

&&

.SHORT TERM...
Issued 1217 AM CDT Sat Jun 27 2026

Today through Tuesday:

Light enely surface winds will continue early this morning as
high pressure remains over the nrn Great Lakes and srn Ontario.
A weak 925-850 mb sely flow will begin the warm, moist
advection aloft and bring north some scattered to sometimes
broken stratus from nrn IL this morning. Some of these clouds
could linger through mid to late morning before dissipating.

For this afternoon, a decaying MCS is expected to mostly
dissipate as it moves into sw and south central WI. 850-700 mb
warm, moist advection will support the MCS across srn MN in the
morning, but it begins to run into very warm and dry mid level
air that will already be in place across srn WI by late this
morning into the afternoon. Only 20 percent chances for showers
and storms is forecast west and north of the MKE metro area.

The low to mid level warm advection will increase late this
afternoon through Mon AM as the high amplitude upper ridge
builds into the Great Lakes. The surface warm frontal passage is
expected Mon AM. Only 20-30 percent chances of showers and
storms are forecast tnt toward central WI, as the very warm and
dry 700 mb air will attempt to inhibit elevated convection. A
hot, humid, and capped airmass will finally arrive by Mon
afternoon with high temps in the lower to middle 90s and
dewpoints in the lower to middle 70s. This will yield heat index
values of 100-108F with similar values expected for Tue.

Gehring

&&

.LONG TERM...
Issued 1217 AM CDT Sat Jun 27 2026

Tuesday night through Saturday:

The heatwave will continue much of the week. The strong upper
ridge axis will gradually shift to the east and south becoming a
west to east upper ridge from the ern Ohio Valley to the ern
Seaboard by Wed and lasting through the week with only minor
weakening. Meanwhile a series of shortwave troughs will continue
to traverse from the wrn USA into the Upper MS River Valley and
nrn Great Lakes. Thus the storm track will mainly remain to the
west and north of srn WI with 500 mb heights at 588 DM or
greater. This continues to place a hot and humid airmass over
srn WI through the week. Extreme Heat Warnings or Heat Advisories
will likely be needed much of the week. Only small chances for
showers and storms toward central WI for Tue nt-Wed with chances
increasing a bit for the remainder of the week.

Gehring

&&

.AVIATION...
Issued 708 AM CDT Sun Jun 28 2026

VFR conditions expected through the majority of today, with MVFR
visibilities possible under storms moving eastward through
southwestern to south-central Wisconsin midday through this
afternoon. These storms will become capable of producing
lightning and some potential for briefly gusty winds. Outside of
storms, expecting increasing southeasterly winds throughout
today, with gusts around 20 kt developing during the afternoon
and evening. Expecting additional storms to develop overnight,
but for coverage to be low (20-40%). Lower ceilings in MVFR to
fuel alternative are expected as these storms develop. Winds
will shift to southwesterly into Monday morning.

MH

&&

.MARINE...
Issued 1217 AM CDT Sat Jun 27 2026

High pressure around 30.0 inches is expected to linger across the
northern Great Lakes and southern Ontario through this morning,
with light north to northeast winds, becoming easterly later
today. Low pressure will then deepen to around 29.3 inches over
the central high plains by this evening, shifting winds to the
southeast over the lake. Winds then shift more southerly and
increase into Monday, as the low lifts into the Canadian
Prairies by Monday evening, and a warm front passes north across
the lake. Breezy southerly winds will continue through at least
Wednesday as low pressure stalls over Canada.

Gehring

&&

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

$$

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