NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 141056
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
556 AM CDT Tue Jul 14 2026

.KEY MESSAGES...

- Hot and humid conditions are expected through most of the
  week. Expect highs in the 90s. Heat indices will reach 100 for
  most locations Tuesday and Wednesday. A Heat Advisory will go
  into effect at noon.

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

&&

.UPDATE...
Issued 600 AM CDT Tue Jul 14 2026

Hot and humid conditions expected today with high pressure
overhead keeping winds light with 925mb temps in the 27-29C
range which may even allow for spots that get close to 100F.
With the dewpoints in the upper 60s to low 70s we should see at
least some spots with heat indices reaching over 100.

Kuroski

&&

.SHORT TERM...
Issued 1137 PM CDT Mon Jul 13 2026

Overnight through Wednesday:

Temperatures will be about 3-4 degrees higher Tuesday than
Monday. Dewpoints should be similar (around 70-71 in the
morning, mixing down to 67-69 in the afternoon). The degree of
mixing is still in question, as winds are expected to be a
little lighter. Regardless, the heat indices will be in the 99
to 103 degree range for most areas. Far southwest WI may have
lower dewpoints again, so less confidence in hitting the exact
criteria there.

Again, low temperatures Tue night will range from 69 west to 74
east, so there will be little relief from the heat for anyone
without A/C.

A very weak surface trough will allow northeast winds to sag
down Lake Michigan Wednesday afternoon. This will be so weak
that it acts like a lake breeze. Given that it arrives so late
in the day, temps will have time to reach their peak which will
be similar to Tuesday. The dewpoints may actually pool up along
the vicinity of this wind shift/front, so they could be a degree
or two higher than Tuesday. Heat indices are expected to top
100F again. The Heat Advisory covers the whole period from Noon
Tuesday through 8 PM Wednesday.

Cronce

&&

.LONG TERM...
Issued 1137 PM CDT Mon Jul 13 2026

Thursday through Saturday:

The jet stream will become oriented northwest to southeast
across Ontario on Thursday. The baroclinic zone will line up
across the Upper Great Lakes, from western Lake Superior to
east central Lake Huron. A few mid level shortwaves are expected
to roll across this zone at times Thursday night through
Saturday. While the main impact to southern WI will be clouds
from the remnants of these storms, there will also be a chance
for showers and thunderstorms. Timing and severity of these for
southern WI is impossible to forecast at this time; we will
still be heavily influenced by the hot/dry ridge, and these
typically take some time to break down.

Temperatures Thu and Fri still have the potential to be in the
lower 90s, with max heat indices also in the mid to upper 90s.
Temperatures and dewpoints should be a notch lower on Saturday,
but confidence is low.

Sunday through Monday:

That baroclinic zone may sink into southern WI for Sunday
(although models have differing opinions of where this front
will be positioned), so that would put us in the area for
thunderstorms to develop overhead or remain strong for any
upstream convection.

Then a mid level shortwave trough is being depicted by most of
the model solutions that is expected to drop through the Upper
Great Lakes sometime between Monday and Wednesday. This system
looks like the dynamics could be strong enough for a fairly
widespread severe event, depending on the time of day it crosses
a particular area. Temperatures will be more toward normal
(lower 80s) for the first half of next week.

Cronce

&&

.AVIATION...
Issued 600 AM CDT Tue Jul 14 2026

Quiet conditions today with light west winds with potential for
later in the day lake breeze to turn winds east near the lake.
Otherwise pockets of river valley fog this morning will clear up
in the next couple hours as well quickly warm up.

Kuroski

&&

.MARINE...
Issued 1137 PM CDT Mon Jul 13 2026

High pressure centered over the heartland from Iowa through
Indiana will continue to bring dry and warm westerly winds
across Lake Michigan through Wednesday morning. A weak low
pressure trough crossing Lake Superior Tuesday will usher a
weak front with a wind shift to the northeast down the axis of
Lake Michigan on Wednesday. Another low will approach from the
Northern Plains Thursday into Friday.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Heat Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-
     WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-
     WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...noon Tuesday
     to 8 PM Wednesday.

LM...None.
&&

$$

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