FXUS63 KMKX 131718
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1218 PM CDT Wed May 13 2026
.KEY MESSAGES...
- Patchy frost tonight
- Dry again Thursday with milder temperatures
- Warm and humid conditions with increasing storm chances late
this week into early next week
&&
.SHORT TERM...
Issued 1218 PM CDT Wed May 13 2026
This afternoon through Thursday:
Clouds will clear out later this afternoon into the evening as
high pressure continues to build in from the west. The high will
move overhead tonight, bringing light winds and mostly clear
skies. Given the dry airmass in place, temps may fall enough for
some patchy frost in the east tonight into early Thursday
morning.
Light southerly winds will develop on Thursday as the high moves
east of the area. Mostly sunny skies are expected tomorrow
outside of isolated to scattered afternoon cumulus. Milder temps
will return, with highs near 70 away from Lake Michigan. Winds
will be onshore much of the day near the lake, resulting in
cooler conditions.
DDV
&&
.LONG TERM...
Issued 1218 PM CDT Wed May 13 2026
Thursday night through Wednesday:
There will be a chance for showers Thursday evening into early
Friday morning as moisture and warm air advection aloft increase
with the passage of a shortwave. Capped precip chances at 50
percent for now given a lot of dry air below 10 kft in model
soundings.
It should be mainly dry and warm on Friday behind the departing
wave. Plenty of sunshine by the afternoon in combination with
breezy southerly winds should result in high temps in the upper
70s to low 80s most places.
The gradient of deeper moisture and higher instability is
expected to be across southern Wisconsin or just south of the
WI/IL state line Friday night. This may open the door for
upstream convection Friday afternoon/evening to roll through the
forecast area Fri night into early Sat. Still some uncertainty
a couple days out with where the exactly the storms will form
and where the moisture/instability will set up overnight, so
only have 30-50% precip chances for now.
Saturday was looking dry, but latest models now have some
deeper moisture and instability lingering across at least the
southern forecast area during the day, keeping the door open for
showers/storms given sufficient forcing from a weak wave, etc.
The moisture and instability make a more definite return on
Sunday per 12Z guidance, with increasing shower/storm chances
later in the weekend as a result. Above normal temps will
persist through the weekend.
Monday continues to look like the most likely period for
widespread showers and storms, with southern Wisconsin solidly
in the warm sector of an approaching low. Though a strong to
severe storm isn't out of the question at times Friday night
through Sunday, the overall setup for a few strong to severe
storms currently looks best on Monday. Shear isn't currently
expected to be particularly strong, but moisture, instability,
and forcing look solid. Plenty of time for models to waffle on
this setup though given it's still a few days out.
Confidence is on the lower end with precip chances for the
Tuesday and Wednesday forecast given model timing differences
with the exit of the early week system and the arrival of a mid-
week low. Temps look cooler, with highs likely back near normal
for Tue/Wed.
DDV
&&
.AVIATION...
Issued 1218 PM CDT Wed May 13 2026
Scattered to broken VFR cumulus this afternoon should decrease
in coverage late afternoon into the evening as daytime heating
is lost and high pressure approaches from the west. Light winds
and mostly clear skies are then expected tonight into Thursday
morning. Southerly winds will pick up a little by the afternoon
hours tomorrow, with winds more southeast to east near the lake
due to a lake breeze developing by late morning. Few to
scattered VFR cumulus will be possible in the afternoon away
from the lake, but otherwise skies will remain mostly clear.
DDV
&&
.MARINE...
Issued 1218 PM CDT Wed May 13 2026
Gusty northwest winds will continue this afternoon, as low
pressure around 29.6 inches over southeast Ontario moves east of
the region. A few gale force gusts may occur, particularly
across northern and eastern portions of the lake. Lighter winds
are then expected tonight into Thursday, as high pressure
around 30.1 inches moves eastward through the region. Breezy
southerly winds are expected to develop Friday, with a few gales
possible Friday afternoon and evening in northern portions of
the lake. South to southwest winds then linger Friday night into
Saturday. Winds should then increase gradually for Sunday, as a
warm front moves northward into the region, ahead of low
pressure around 29.2 inches in the central Plains.
DDV
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 4 PM
Wednesday.
&&
$$
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