853 
FXUS63 KMKX 182024
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
324 PM CDT Sat Oct 18 2025

.KEY MESSAGES...

- Dry weather through early this evening.

- Rainshowers expected late this evening through Tonight,
  tapering from west to east Sunday morning. A few rumbles of
  thunder will be possible, particularly towards southeastern
  Wisconsin. 

- Gusty northwest winds and much cooler for Sunday (highs in the
  upper 50s). 

- Continued cool weather this coming week, with frost potential
  several nights. 

&&

.SHORT TERM...
Issued 320 PM CDT Sat Oct 18 2025

Tonight through Sunday night:

The cold front is on track to arrive this evening, though the
more robust support and triggering for showers (and perhaps a
few thunderstorms) associated with 500mb PVA should kick things
off around or after 10 PM CDT this evening. The 12z HREF mean 
MUCAPE indicated roughly 500 to 750 Joules reaching far 
southeastern WI, hence we opted to leave the chance / slight
chance thunder probabilities in the forecast there. Mostly just
rain showers further north and west.

Gusty northwest winds behind the front will arrive on a delay
behind the initial NW wind shift (after midnight), becoming 
gusty late tonight into Tuesday, with gusts to around 35 MPH 
expected. The rain wraps up in a west to east manner through 
Sunday morning, leaving the afternoon dry with continued gusty
winds and rapidly decreasing cloud cover. Much cooler (highs in
the upper 50s).

Winds rapidly subside under clear skies Sunday night, with a
brief surface ridge passing overhead. This will set the stage
for frost potential late Sunday night into early Monday morning.
Our forecast does currently call for 'areas of frost' to form 
in said time window, affecting most inland areas and as far east
as the Kettle Moraine hills. Closer to the Lake Michigan
shoreline, our forecast currently resolves temperatures and
dewpoints roughly 2-3 degrees warmer, making frost formation
slightly less likely.

Sheppard

&&

.LONG TERM...
Issued 320 PM CDT Sat Oct 18 2025

Monday through Saturday:

Synopsis: 
The brief surface ridge exits east on Monday, working with a low
pressure system over the Dakotas / Minnesota to drive strong
surface WAA in our region, with breezy south winds boosting
daytime high temps back into the mid 60s for Monday afternoon.
The warmth will be short lived as the aforementioned low
pressure system drags a cold front across the region Monday
night (though models remain dispersed on the exact arrival
time). 60-70% rain chances Monday evening and night as the front
crosses. Winds veer west and intensify behind the front, with
Tuesday looking gusty and cool (highs in the low 50s). Some 
20-50% rain chances linger in eastern and east-central WI on 
Tuesday with some models allowing precip to wrap around the back
side of the departing low pressure. Far southwestern WI looks 
to remain dry (only 10-20% rain chances Tuesday) further from 
the parent low pressure. Predominantly dry weather through the 
rest of the forecast period, with only slight (~15%) rain 
chances on account of a central Great Plains low pressure that 
may meander just close enough by. 

Mid-Week Frost Potential: 
The two main windows we will be watching are late Wednesday
night into Thursday morning and late Thursday night into Friday
morning. Cloud cover and lingering light winds may play a role
in raising/lowering frost potential one or both days, a lot
could change from this far out. For the first of these two time
frames, our minimum temperature forecast currently sits in the 
low 30s, with low to mid 30s for the latter. 

Late-Week Temp Trends remain uncertain:
The GFS ensemble allows light southwesterly winds to become
established late next week, with a gradual warming trend into
the 60s. On the other hand, the ECMWF ensemble depicts steady 
state high temps with highs remaining around 50 late next week.

Sheppard

&&

.AVIATION...
Issued 320 PM CDT Sat Oct 18 2025

Dry weather and VFR through the rest of the afternoon.
Widespread rain showers expected late this evening through
tonight as a cold front passes through, with slight potential
for some weak thunderstorms mixing in for southeastern
Wisconsin. Gusty northwest winds behind the cold front will
arrive after midnight CDT (though the initial wind shift to NW 
will occur earlier in the evening/night). NW wind gusts up to 30
KT continue into Sunday, gradually subsiding Sunday evening. 

Tonight's rainshowers bring the potential for lowered cloud
ceilings, which are forecast to reach MVFR for much of southern
and eastern Wisconsin late tonight through Sunday morning.
Ceilings rapidly improve to VFR altitudes by around mid day
Sunday, breaking apart and clearing out into Sunday afternoon. 

Sheppard

&&

.MARINE...
Issued 320 PM CDT Sat Oct 18 2025

Modest southerly winds continue through the early evening hours. 
Low pressure is expected to move in from the Great Plains across 
IL and northern IN tonight, and rapidly deepen to around 29.2 
inches as it lifts into the Lower Michigan Sunday morning, 
reaching Lake Huron by mid day Sunday. This will drag a strong 
cold front across the lake, resulting in northwest gales early 
Sunday morning through Sunday evening.

Winds briefly weaken late Sunday night into early Monday, then
turn south and accelerate to roughly 30 knots mid day Monday as
29.5 inch low pressure tracks east across northern Minnesota. This
low will then drag another cold front across the lake Monday
night, with west gales looking likely behind the front late Monday
night through Tuesday night, possibly into Wednesday as the 
aforementioned low pressure lingers over southern Canada.

Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Gale Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
     LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
     LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM Sunday 
     to 10 PM Sunday.

     Gale Warning...LMZ643-LMZ644-LMZ645-LMZ646...7 AM Sunday to 7 
     PM Sunday.

&&

$$

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