NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 291157
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
657 AM CDT Mon Jun 29 2026

.KEY MESSAGES...

- Extreme Heat Warning in effect for all of southern WI noon
  today through Tuesday evening. Additional heat headlines will
  likely be needed for the middle to late portions of the week
  as this prolonged heatwave continues.

- Isolated showers and storms  Then additional daily storm
  chances Tuesday night through the end of the week as the hot
  and humid pattern continues.

- High swim risk conditions for Ozaukee and Sheboygan County
  beaches today, with moderate swim risk conditions for
  Milwaukee and Racine Counties.

&&

.UPDATE...
Issued 657 AM CDT Mon Jun 29 2026

Dewpoints of 72 to 76 degrees have advected in overnight, with
strong warm and moist advection continuing through today.
Expecting heat index values to easily reach Extreme Heat Warning
criteria. With such high dewpoints, also not anticipating
temperatures to fall below 75 degrees tonight. High swim risk
conditions are expected for Ozaukee and Sheboygan County Lake
Michigan beaches through 10 PM CDT, with moderate swim risk
conditions for Milwaukee and Racine Counties. Stay out of the
water if in a high swim risk area. Avoid dangerous areas such as
piers and breakwalls!

MH

&&

.SHORT TERM...
Issued 1044 PM CDT Sun Jun 28 2026

Tonight through Tuesday:

The nose of a sly low level jet around 35-40 kt will remain over
nrn and central WI tnt. Thus new elevated showers and storms
will develop over this region due to the low to mid level warm,
moist advection and embedded frontogenesis. Believe the 12C
isotherm at 700 mb will remain a good indicator of capping to
the south, while enough lift and moisture for storms will
prevail to the north. Thus east central WI will at least be on
the srn periphery of this new area of convection. Forecasting 50
percent chances toward central WI late this evening and
overnight with only slight chances from Madison to Milwaukee.

The surface warm front will then pass nwd through srn WI from
09-15Z Mon as low pressure tracks from the central high plains
into the Dakotas. A hot, humid, and well capped airmass will
then prevail for Mon-Tue. High temps in the lower to middle 90s
with dewpoints in the middle 70s will yield heat index values of
100-110F. An Extreme Heat Warning is in effect.

Gehring

&&

.LONG TERM...
Issued 1044 PM CDT Sun Jun 28 2026

Tuesday night through Sunday:

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 through Thu 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 20-40
percent chances for showers and storms toward central WI for Tue
nt-Wed nt with chances increasing a bit for late in the week
and weekend as shortwave troughs arrive in wly flow aloft.

Gehring

&&

.AVIATION...
Issued 657 AM CDT Mon Jun 29 2026

A few patches of fuel alternative ceilings have developed
across south-central to southwestern Wisconsin this morning.
These are expected to lift and scatter out within the next
couple hours. After clouds lift and scatter, expecting VFR
conditions to prevail throughout the TAF period. Gusty
south-southeasterly winds of 20-25 kt starting midday and
continuing into this evening. Overnight, expect wind gusts to
diminish but LLWS to develop. Winds will shift to southwesterly
overnight, becoming gusty around 20 kt again Tuesday morning.

MH

&&

.MARINE...
Issued 1044 PM CDT Sun Jun 28 2026

Low pressure around 29.2 inches in eastern Colorado will track to
eastern North Dakota by Monday afternoon. Its warm front will
move north across Lake Michigan on Monday. Light to modest
easterly winds this evening will become breezy southeasterly
winds late tonight and Monday morning over the lake. Breezy
south winds will then prevail from Monday afternoon into the
middle of the week. Modest southerly winds will then prevail for
Thursday into Friday. Areas of dense fog may develop at times
this week due to a very humid airmass flowing over the
relatively cooler waters of the lake. Scattered thunderstorms
are forecast on most days especially over the north half.

Gehring

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060 until 10 PM Monday.

LM...Small Craft Advisory...LMZ643 until 10 PM Monday.

     Small Craft Advisory...LMZ644-LMZ645-LMZ646...noon Monday to
     10 PM Monday.

&&

$$

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