089
FXUS63 KMKX 160856
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
356 AM CDT Thu Oct 16 2025

.KEY MESSAGES...

- Light rain is possible (15-30%) today through this evening.

- High temperatures will be well above normal Friday and
  Saturday with highs in the 70s.

- Showers with a few thunderstorms are expected along a slow-
  moving cold front late Friday night through Saturday night.

&&

.SHORT TERM...
Issued 356 AM CDT Thu Oct 16 2025

Today through Friday:

Light showers are ongoing across portions of IA and southern MN
early this morning. They are concentrated along an area of 925mb
frontogenesis, but there is ascent ongoing between the surface
and 850mb, and therefore there is fairly widespread coverage of
these showers. The showers associated with the 925mb level are
inching eastward into far western WI including Grant County
already. The showers and thunderstorms over central IA will
continue eastward and miss us - they might be associated with an
MCV.

While the 925mb front is not expected to make a lot of eastward
progress into south central WI today, the 850mb front will
slowly cross all of WI. Lift will be aided by the right entrance
region of the upper jet and potentially some weak vorticity
advection. Kept the low chances (15 to 30 percent) confined to
areas west of Madison this morning, and then walked low chances
(15 to 25 percent) across all of southern WI through the
afternoon. Amounts will be light, less than a tenth of an inch.

Low pressure deepening and occluding over North Dakota and
Manitoba will lead to increasing southerly winds over southern
WI Friday morning. There should be high clouds overspreading
the whole region due to upper divergence with the jet and mid
level warm air advection. The 925-850mb temps will also be on
the rise, and we can expect high temperatures to top out in the
mid 70s, despite the clouds. Dry weather is expected for
southern WI until at least sunset.

Cronce

&&

.LONG TERM...
Issued 356 AM CDT Thu Oct 16 2025

Friday night through Wednesday:

Synopsis: Mean upper troughing will be the predominant large scale
feature across the central CONUS from Friday night into Sunday. Two
smaller-scale waves will pivot through the area of mean troughing
during this time frame, helping to bring unsettled conditions to
southern Wisconsin Friday night through Saturday evening. The first
of the two waves will move from the US-Canada border toward the
Hudson Bay Friday night, pulling an area of surface low pressure
into northwest Ontario by early Saturday morning. The second of the
two waves will then drive into the area from the Northern Plains
Saturday afternoon, inducing secondary surface cyclogenesis across
the western Great Lakes Saturday night. The progression of upper
waves & attendant surface lows will help to pull a cold front toward
southern Wisconsin Friday night, with the boundary slowly
progressing through & east of the area by Saturday evening. Showers
& embedded thunderstorms are thus expected during this time frame.
Peak timing windows for precip, and whether/not multiple rounds of
precip will occur, will depend on quickly the cold front crosses
southern Wisconsin. Cooler and dry conditions will prevail behind
the departed cold front Sunday through Monday. Rain chances return
Tuesday into Wednesday ahead of the next disturbance.

Friday Night through Saturday Night: An active period of weather is
forecast as a cold front slowly works through the region. Current
guidance suggests that there could be two favored windows for
rainfall, with the first focusing along the arriving front Friday
night. A second round would then be possible Saturday afternoon &
evening along the lingering surface front/ahead of the approaching
upper wave. Development of the second round would be contingent on
the front remaining over the area into Saturday afternoon, with
model solutions still in disagreement over its precise positioning
during the day on Saturday. Will thus be monitoring trends regarding
the evolution of the surface pattern following Friday night`s rain,
as this will be the driving factor over how much (if any) of
southern Wisconsin sees additional precipitation on Saturday.
Forecast soundings do show some instability, pointing toward the
potential for embedded thunderstorms in any round of activity. Given
precipitable waters generally in the 1-1.3" range, brief heavy
downpours would be a possibility in embedded storms. Flooding
potential appears low at this time, though trends will continue to
be monitored in coming forecasts. Primarily overnight timing of the
first round and abundant cloud cover ahead of a possible Saturday
second round should keep widespread severe weather potential well
south of the region. Will continue to watch model trends closely
through this portion of the period.

&&

.AVIATION...
Issued 356 AM CDT Thu Oct 16 2025

A few low clouds with bases around 2500 ft are impacting
lakeshore areas of southeast WI early this morning, but they
should be brief.

Clouds are clearing over east central WI, but the clearing will
stall this morning as an upper level front approaches from IA
and MN. Ceilings are VFR for east central and most of southern
WI, with MVFR ceilings west of a line from the Dells to Madison
to Janesville. While this line may see a brief period of
ceilings dropping to 2500 ft this morning, the overall VFR is
expected to continue through the afternoon.

An area of light showers may track from west to east across
southern WI this afternoon. Ceilings should remain VFR but a
brief drop to 2500 ft is possible. Non-convective low level wind
shear will be possible late tonight.

Cronce

&&

.MARINE...
Issued 356 AM CDT Thu Oct 16 2025

High pressure centered over Lake Superior will weaken as it
reaches the lower Great Lakes this evening. Low pressure around
29.6 inches developing in the Northern Plains today will lift
into Manitoba by early Friday morning while strengthening and
occluding. This low will further deepen as it tracks northeast
toward Hudson Bay Friday night.

Southeast winds over Lake Michigan today will become breezy
tonight into Friday morning. Gusty southerly winds are expected
Friday and Friday night as an associated cold front approaches
from Minnesota. Southerly gale force gusts will be possible Friday
afternoon and evening.

Showers and a few thunderstorms are expected along this front as
it slowly crosses Lake Michigan Saturday through Saturday night.
Meanwhile, low pressure around 29.3 inches will develop over
Wisconsin Saturday night and cross eastern Ontario Sunday
afternoon. A period of strong northwest winds is expected Sunday
through Sunday evening. Gale force gusts are looking likely,
especially over the south half of Lake Michigan.

Nearshore areas of southeast WI will see increasing southeast
winds today. The persistent winds will build high waves by late
evening. Gusty south winds and high waves are expected Friday
through Saturday morning. A Small Craft Advisory is in effect.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...1 AM
     Friday to 10 AM Saturday.

&&

$$

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