NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 151027
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
527 AM CDT Wed Jul 15 2026
.KEY MESSAGES...
- Hot and humid conditions continue through Wednesday with highs
in the 90s and heat indices around 100F each afternoon for
much of southern WI. A Heat Advisory continues this afternoon
through Wednesday.
- WI DNR issued Air Quality Alert for all southern WI through
Thursday for unhealthy to very unhealthy conditions.
- Wildfire smoke from across northern MN and northwestern
Ontario is progged to push southward into southern WI as
early as Wednesday evening and continue through Thursday
contributing to unhealthy air quality as well as limiting
temps by a few degrees.
- Shower and storm chances gradually increase for the end of the
week into the weekend.
&&
.UPDATE...
Issued 530 AM CDT Wed Jul 15 2026
Warm temperatures continue into today with high temperatures
expected in the mid 90s but higher dewpoints will lead to heat
indices in the 98-104 range, which was why the Heat Advisory
remains in effect. Otherwise we will start to see air quality
degrade toward east central WI as smoke slides south from the
fires in Minnesota and south central Canada. This will decrease
visibilities a bit with smoke expanding southward this
evening/tonight.
Kuroski
&&
.SHORT TERM...
Issued 1212 AM CDT Tue Jul 14 2026
Tonight through Thursday night:
Temperatures are slowly dropping tonight and are expected to dip
into the mid to low 70s. Dewpoints are expected to remain
fairly similar overnight in the upper 60s to low 70s. This will
provide little relief to those without AC. The Heat Advisory
remains in effect for all of southern Wisconsin due to the warm
overnight temperatures and hot, humid conditions expected today.
Highs in the mid 90s with dewpoints in the upper 60s to low 70s
will put heat indices back to 100-105.
Looking back really quick at the rest of tonight, there will be
a potential for fog to develop mainly for areas west of
Interstate 90. Any fog that develops is expected to be patchy
and should burn off shortly after sunrise.
Dry weather is expected through the rest of the day. The upper
level jet will start to shift later in the day leading a more
favorable pattern for smoke to move in from Minnesota and
Canada. Northwest winds aloft will bring the smoke overhead
while the sfc high pressure (subsidence) brings it to the sfc.
Guidance continues to favor smoke making it to the sfc in
southern Wisconsin tonight. Reduction of visibilities and poor
air quality are expected for at least portion of the forecast
area through at least Thursday. Smoke may linger into Friday,
but will have to monitor trends for that. Given the smoke
overhead and at the sfc, temperatures are likely to be impacts
during the day Thursday. Thus lowered the daytime highs into the
80s across the area with upper 70s along the lakeshore. There is
an argument that in combination with easterly winds that
temperatures could be end up being lower than this, but took a
slightly more conservative approach to prevent giving an all
clear on the heat just yet.
With the changing upper level pattern hinted at above there will
be a chance(10-30%) for a few isolated showers and storms
Thursday as well. With a lingering hot and humid air mass as
well as a retreating high pressure Thursday, there just needs to
be a bit of sfc convergence to get some isolated showers to
develop. Then anything that throws down an outflow will likely
generate a few more and so forth.
Patterson
&&
.LONG TERM...
Issued 1212 AM CDT Tue Jul 14 2026
Friday through Tuesday:
With the high pressure lingering and a weak cold front across the
Great Lakes Region, near sfc smoke may remain a problem heading into
Friday. The large scale subsidence and northerly winds aloft should
keep air moving in and funneling toward the sfc, it just comes down
to how much longer the high pressure will be overhead. And just how
much smoke has dispersed in general.
An upper level ridge is expected to ride over the top of the
receding ridge heading into the weekend which will open the
door to a few chances for rain and thunderstorms. This change of
the pattern could work both in our favor for abating the 90
degree temps and limiting the near sfc smoke.
The best chance for some isolated showers and storms looks to be
Friday afternoon into Saturday with an approaching low pressure
system. This low is generally expected to move from the Northern
Plains through the northern Great Lakes Region and then toward the
New England States. There is still some uncertainty in the
track of this low. Confidence in rain has grown despite this due
to the fact that a cold front will drag across the state. So
whether the track is further north or not leaves a slightly moot
point in there will be rain its just more of a duration and
coverage type question. Colder air is expected to moved in
behind the low and front which will bring some more relief from
the 90s for Sunday. Additional showers and thunderstorms look to
hold off until early next week with guidance suggesting another
trough swinging down from the Hudson Bay area. With this second
low from the north, temperatures hint at further cooling with
some members of guidance suggesting we may see some upper 70
temperatures which is right around normal for this time of year.
If you consider the 6-10 day outlook for the CPC there is even
a chance for slightly below normal temperatures so those looking
for some relief from the heat have a light at the end of the
tunnel.
Patterson
&&
.AVIATION...
Issued 530 AM CDT Wed Jul 15 2026
Quiet conditions to start today with VFR conditions but
gradually smoke will slide in from the north that should
slightly impact VSBYS to as low as IFR though mostly expected to
be VFR to MVFR. The biggest impacts will be to the east and more
specifically east central WI. Impacts will start at SBM this
afternoon and impacting areas further south by the early to mid
evening continuing into at least Thursday morning.
Kuroski
&&
.MARINE...
Issued 1212 AM CDT Tue Jul 14 2026
Dry, warm weather and westerly winds are expected across the
lake through this morning as high pressure lingers over the
Great Lakes Region. A weak area of low pressure will gradually
work its way across Lake Superior and down across the lake
through the day. This will push the high pressure out and
bringing a northeasterly wind shift across the Lake heading into
Thursday. Will see lighter winds on Thursday as high pressure
briefly builds back in before another low pressure moves in from
the Northern Plains for the weekend. Southwest to south winds
will set up across the lake Friday ahead of this low. Winds will
shift to northerly behind a cold front that is expected to move
down the lake toward the end of the weekend. Additionally will
see periodic shower and thunderstorm chances across the lake for
the end of the week through the weekend.
Patterson
&&
.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 until 8 PM
Wednesday.
LM...None.
&&
$$
Visit us at weather.gov/milwaukee
Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee