395
FXUS63 KGRB 181732
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1232 PM CDT Sat Oct 18 2025

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- Warm today, with highs in the upper 60s to middle 70s.
  Temperatures trend cooler beginning Sunday.

- Showers and a few thunderstorms end in eastern Wisconsin early
  this morning, then return late tonight into Sunday morning.

- Windy conditions expected on Sunday as northwest winds gust to
  25 to 35 mph.

&&

.DISCUSSION...
Issued at 332 AM CDT Sat Oct 18 2025

Showers and scattered thunderstorms were increasing across the Fox
Valley and lakeshore areas early this morning, in response to the
approach of a weak cold front, the RRQ of an upper level jet
streak, PWATs of 1.25-1.50 inches and MUCAPE of 200-400 j/kg.
These showers and storms are expected to shift east of the region
by 12z-13z/Sat. Clearing skies and decreasing winds over north
central and central WI will lead to patchy fog development
through daybreak.

Clearing skies over the northwest part of the CWA will progress
through eastern WI this morning. The resulting sunshine will
boost temperatures in the middle 60s to middle 70s regionwide this
afternoon. Another cold front will move through the northwest
half of the forecast area this afternoon, with little impact
other than a wind shift to the west.

A short-wave trough lifting northeast from the Texas Panhandle and
another potent short-wave approaching from the Northern Plains
will phase over the western Great Lakes tonight. This will induce
rapid cyclogenesis along the cold front as it shifts east into
Lower Michigan late tonight into Sunday morning. As this occurs,
widespread light to moderate rain will fill in across the forecast
area. Rainfall amounts will be fairly light over the northwest
part of the forecast area, while locations in the eastern Fox
Valley and lakeshore areas could see upwards of a quarter to half
inch. Winds will start to crank up late tonight, with northwest
gusts reaching 25 to 35 mph on Sunday.

Rain tapers off by Sunday afternoon, with a surface ridge bringing
dry weather through Monday morning. Another cold front and short-
wave arrives Monday afternoon afternoon and evening, along with
potential for widespread light to moderate rainfall, which should
continue through Tuesday. Small precipitation chances linger
though the mid part of the work week, especially over the
northeast half of the forecast area. Drier conditions should
return later in the week.

After one last very warm day today, temperatures are expected to
trend cooler through the middle of next week. The coolest day is
expected on Tuesday, when highs only reach the 40s to lower 50s.
Another stretch of mild weather is poised to return later next
week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1231 PM CDT Sat Oct 18 2025

VFR conditions will persist through late this afternoon. Winds
will be light. Scattered to broken MVFR ceilings may briefly
spread in from northwest WI to northern WI (RHI) by this evening.
Overnight tonight, low pressure will develop and deepen just to
our south and east. This will result in increasing rain chances
regionwide. Local MVFR conditions may develop in eastern WI late,
lasting into mid morning on Sunday. NW winds will increase
overnight into Sunday morning, especially in eastern WI where
gusts may reach or exceed 30 kts.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Kieckbusch
AVIATION.......JLA