883
FXUS63 KMKX 180118
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
818 PM CDT Fri Oct 17 2025

.KEY MESSAGES...

- Showers (50-80%) and a few thunderstorms are expected along a
  weak cold front late this evening into Saturday morning. Then
  looking dry through the day Saturday with the front pushing
  further southeast.

- Windy and colder for Saturday night and Sunday with widespread
  rain (70-90%) for late Saturday night lingering into Sunday
  morning.

&&

.UPDATE...
Issued 818 PM CDT Fri Oct 17 2025

A narrow band of showers ahead of an approaching sfc-700 mb
trough extends from sw WI to ern KS. The trough will slowly move
across srn WI tnt through Sat AM and continue to weaken as it
does so. PWATs of 1.3 inches and fairly moist soundings are
expected within the band as it moves into south central WI. Rain
chances of 70-80% are forecast over south central WI dropping
slightly to 50-60% for ern WI due to the weakening. Clearing
skies are then expected for much of srn WI by late Sat AM but
clouds will likely linger over far se WI into the afternoon.
Temps will warm once again into the 70s.

Gehring

&&

.SHORT TERM...
Issued 307 PM CDT Fri Oct 17 2025

Tonight through Sunday:

The cold front stretched from northwest WI down through
southeast MN continues to gradually push eastward through the
evening. Will begin to see a return of showers ahead and along
the frontal boundary as it aligns with the tail-end of the 30-40
kt 850mb LLJ and ahead of swath of mid-level dCVA extending
southward from the vorticity center further north. PWATs are
looking to rebound back above 1 inch ahead of this boundary this
evening. Thus forcing combined with moisture return looks to be
enough to develop a broken line of showers with a potential for
a few rumbles of thunder given CAMs hinting at MUCAPE building
to between 200-500 J/kg. This broken line begins to push into
far western portions of the CWA between 02-06z this evening and
will gradually slide southeastward overnight reaching the
lakefront around or just before daybreak (10z-12z).

Overall, today`s 12z-18z model runs continue the trend of
having this front push southeast of WI through the morning of
Saturday as the upper-level trough is progged to be further east
than previous day runs. Thus resulting in a drier forecast for
southern WI during the day Saturday with post-frontal westerly
wind shift, while the higher rain chances shift further east
into MI/northern IN. Still cannot rule out some lingering
showers in far southeastern WI through the mid-morning hours,
but trending drier overall.

Rainfall totals from 00z Sat-00Z Sun are looking much lest than
previous forecast as well ranging from a few hundredths to less
than a quarter of an inch. Areas that do see a storm with more
persisting rainfall may end up with locally higher amount
closer to half an inch, but generally remain an inch.

With Saturday looking drier, expect some clearing behind the
frontal passage with light westerly winds expect mild temps
creeping back into the 70s through the day.

This warm up will be short lived as upstream upper-level trough
and shortwave trough is progged to phase over the Plains later
Saturday. This developing trough will lift across the Midwest
into Sunday and the associated surface low will follow suit. As
it tracks from IL into IN/MI, mid-range global models and
ensembles continue to show this feature undergoes cyclogenesis
and deepen to sub-1000mb as it lift northeastward into eastern
Ontario. While this feature traverses into the Great Lakes
region, it will bring a slug of moisture (PWATs around 1-1.2
inches) clipping southern and east- central WI on the backside
the deepening low overnight Saturday with CAA wrap around shower
potential into Sunday. May see an additional few tenths to
around three-quarters of an inch of rainfall with this round of
showers. Temps will quickly fall behind this system with
overnight lows Saturday falling into the 40s and highs on Sunday
only in the 50s to around 60F. Will also see the pressure
gradient tighten into Sunday as the low deepens with some model
hinting at sub-990mb resulting in strong northwesterly winds for
Sunday with gusts of 25-35 mph possible inland and stronger
gales over Lake Michigan.

Wagner

&&

.LONG TERM...
Issued 307 PM CDT Fri Oct 17 2025

Sunday night through Friday:

Winds ease Sunday night as upper-level ridge builds across the
Upper Midwest and surface high passes to the south of WI. Will
see temps rebound on Monday back into mid to upper 60s as winds
shift back to the south. Meanwhile another trough is progged to
deepen across the Plains overnight Monday into Tuesday. Looking
at another deepening low pressure trekking across the Upper
Great Lakes Tuesday. This will bring another round of strong
gusty winds to WI and Lake Michigan. Then a quieter/less active
pattern looks likely for the middle of next week as ridge builds
back across the central CONUS.

Wagner

&&

.AVIATION...
Issued 818 PM CDT Fri Oct 17 2025

A north to south band of showers and isolated storms will
slowly move east across srn WI from late this evening through
14Z Sat. Cloud bases with the rain will initially range from 5-8
kft than fall to MVFR Cigs for a few hours. The MVFR Cigs will
occur over south central WI from 08-12Z Sat and over portions of
ern WI from 10-17Z Sat. Brief 3-5SM BR may occur with the rain.
VFR conditions will then return for the remainder of Sat.

Gehring

&&

.MARINE...
Issued 307 PM CDT Fri Oct 17 2025

Southerly winds up to 30 knots will linger through the start of
the evening, but will gradually ease across Lake Michigan
tonight as a cold front extending off of a low pressure works
its way across Manitoba/western Ontario tonight. The cold front
will push across the lake overnight into Saturday morning with a
westerly winds shift behind the front. Another low pressure is
expected to move in from the Plains across IL and northern IN
Saturday night then rapidly deepens as it lifts into the Lower
Michigan Sunday morning. by midday Sunday it looks to move
toward Lake Huron. This will drag a much stronger cold front
across the lake with a tighter pressure gradient resulting in
gales Sunday morning into Sunday evening. Winds briefly weaken
for Monday, but additional gales will be possible on Tuesday as
another deepening low pressure moves through the region.

Wagner

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 10 AM
     Saturday.

     Gale Watch...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ643-LMZ644-LMZ645-LMZ646-LMZ669-LMZ671-LMZ673-
     LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
     LMZ878...7 AM Sunday to 10 PM Sunday.

&&

$$

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