NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 280517
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1217 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 beginning Monday.

- Only slight chances for showers and storms this afternoon and
  tonight north and west of the MKE metro area. Chances for
  showers and storms increase a bit for mid to late week.

&&

.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 1217 AM CDT Sat Jun 27 2026

VFR conditions will prevail today and this evening, but local
MVFR Cigs may occur at times early this morning as a moist sely
flow begins at 925-850 mb and stratus moves nwd from nrn IL. Low
stratus (600-1500 ft.) are then expected to develop over much
of srn WI late this evening into the overnight as the warm front
approaches.


Gehring

&&

.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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