499 
FXUS63 KMKX 180757
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
257 AM CDT Sat Oct 18 2025

.KEY MESSAGES...

- Showers and thunderstorms push east early this morning,
  followed by dry weather from mid morning through early
  evening.

- 60%-90% chance for rain tonight, followed by windy and much 
  cooler conditions on Sunday. 

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

&&

.SHORT TERM...
Issued 257 AM CDT Sat Oct 18 2025

Today through Sunday:

A weak cold front is bringing showers and thunderstorms to the
region this morning. Rain chances will push eastward with the
front over the next several hours, with precipitation east of
the area by mid morning. Dry mid level air will build in from
the west, which will bring dry and mostly sunny conditions for
most of the day today. Highs will remain on the warm side, with
readings in the mid 70s. 

Big changes arrive tonight as a deep trough swings through the
upper Mississippi Valley, and low pressure rapidly deepens
across northern Indiana and lower Michigan. Widespread (60%-90%
PoPs) showers and a few thunderstorms will develop across the
region this evening into the overnight in response to the 
approaching trough. A strong cold front will then sweep across
the area overnight, with gusty west to northwest winds expected
behind the front for Sunday. Though partly to mostly sunny
conditions are expected, highs will only be in the mid to upper
50s.  

Boxell

&&

.LONG TERM...
Issued 257 AM CDT Sat Oct 18 2025

Sunday night through Friday:

The ECMWF Ens and GEFS continue to have fairly good agreement for
next week. A brief and quick moving sfc ridge will move across S 
WI Sun nt followed by sly winds and warm advection on Mon ahead of
a fairly strong upper trough that will track from the Canadian 
Prairies to the nrn Great Lakes. Another strong shortwave trough 
will track from the central Rockies into the wrn Great Lakes, 
thereby merging with the Canadian trough. Cyclogenesis will then 
ensue and take much of Tue-Tue nt crossing the nrn Great Lakes. 
The details of the cyclogenesis will likely change a bit each day,
but showers will be possible (30-50%) Mon nt with the cold 
frontal passage. Small chances for showers may continue Tue into 
Tue nt via low level instability and weak shortwave trough 
passages on the back side of the low. Brisk nnwly winds and much 
cooler temps will prevail Mon nt-Tue nt. 

Nwly flow aloft will then prevail Wed through Fri but with 500 mb
heights gradually rising. Weak vorticity maximums may bring slight
chances for showers, but overall dry weather with temps warming  
back to normal is forecast. 

Gehring

&&

.AVIATION...
Issued 257 AM CDT Sat Oct 18 2025

Showers and occasional thunderstorms will continue to impact the
terminals early this morning. Brief reductions in both
visibility and ceilings to MVFR are possible at times. Activity
will push eastward over time, clearing the eastern terminals by
mid morning. Dry and breezy conditions are then expected for 
most of the day and into the early evening hours. 

A strong cold front will bring additional rain and thunderstorm
potential tonight. MVFR ceilings are possible, especially over
eastern Wisconsin. Winds will become gusty from the west and
northwest on Sunday behind the front.  

Boxell

&&

.MARINE...
Issued 257 AM CDT Sat Oct 18 2025

Modest southerly winds are expected today 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 
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.

Gale Warnings are now in effect for the open waters and
nearshore on Sunday. 

Boxell

&&

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

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

     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.

&&

$$

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