NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 130444
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1144 PM CDT Sun Jul 12 2026

.KEY MESSAGES...

- Hot and modestly humid conditions are expected through most of
  the week. Expect highs in the 90s. Heat indices may reach 100
  on Tuesday.

- Dry weather is expected through Thursday, with thunderstorm
  chances returning late in the week.

&&

.SHORT TERM...
Issued 1144 PM CDT Sun Jul 12 2026

Overnight through Tuesday:

Winds will become westerly across southern WI as the center of
the high sinks into IA and IL. The hottest temps will be north
of the ridge, so across MN and WI. In fact, there will be a temp
gradient from around 100 in far northeast WI and Upper MI to
around 90 in far southwest WI. High temperatures across southern
WI will be in the lower to mid 90s. We have very dry air over
the region, and mixing will limit our afternoon dewpoints to the
mid-upper 60s. Therefore, heat indices are only expected to max
out in the 90s- highest toward east central WI. The heat
advisory criteria is 100, so we are holding off issuing a
headline at this time.

Tuesday will be a little warmer with highs in the mid to upper
90s, but still with afternoon dewpoints in the 60s. With this
subtle difference, we could see some heat indices top 100,
mainly east of Madison. The forecast temperatures are lining up
with the 75th percentile among many model solutions for Monday
and Tuesday. This leads to a little uncertainty about
forecasting too warm, but models tend to have a cool bias in
these extreme patterns. The other uncertainty is the dewpoints.
We should be able to mix out a little each afternoon to prevent
dewpts from getting above 70, but evapotranspiration may play a
role in bumping them up a degree or two.

Cronce

&&

.LONG TERM...
Issued 1144 PM CDT Sun Jul 12 2026

Wednesday through Sunday:

The upper level ridge will flatten over the Great Lakes Tue nt
as an upper low slides across James Bay. This feature will push
a weak cold front over northern Lake Michigan Wednesday morning,
but there is not enough forcing to push the front all the way
into southern WI or southern Lake Michigan, but it should
basically help enhance the lake breeze here Wednesday
afternoon. Therefore the high temperatures should be similar to
Tuesday before they drop with the lake breeze. Dewpoints may
actually be closer to 70 this day due potential pooling along
the front. We will continue to monitor for the need of a Heat
Advisory.

The models continue to trend toward a more persistent ridge over
the Midwest which means southern WI will remain in this hot
weather pattern. Some models are showing storm complexes
developing over the MN Arrowhead and Lake Superior and tracking
southeast along this stationary boundary at times Thu nt
through Sat. This scenario introduces the chance for showers and
storms in portions of southern WI (mainly toward east central)
Friday through Saturday. While we will continue to be under that
warm air mass, extra clouds in the region should help keep them
lower than the Mon-Wed levels.

It looks like there is some relief from the hot and humid and
dry conditions by Sunday and early next week. An upper trough is
expected to swing across the Upper Great Lakes during this time.

Cronce

&&

.AVIATION...
Issued 1144 PM CDT Sun Jul 12 2026

Overall, expect clear skies and nearly calm winds that favor a
westerly direction through Monday morning. Look for westerly
winds up to 10 kt Monday with mostly sunny skies. A lake breeze
will remain close to the shoreline, but could make it to KMKE by
late afternoon. Hot and modestly humid conditions are expected
Monday through Wednesday and may linger through the end of the
week.

Cronce

&&

.MARINE...
Issued 1144 PM CDT Sun Jul 12 2026

High pressure over the Great Lakes region will maintain an axis
roughly from northern Iowa to southern Lower Michigan through
Monday and then sink into Illinois and Indiana Tuesday and
Wednesday while weakening. Low pressure will approach from the
Northern Plains Thursday into Friday. Look for winds to become
south- southwesterly for Monday and Tuesday. A weak cold front
will bring a wind shift to the north- northeast Wednesday into
Thursday.

Cronce

&&

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

$$

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