Ashippun, Wisconsin Weather Forecast Discussion

908
FXUS63 KMKX 011926
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
226 PM CDT Wed Oct 1 2025
.KEY MESSAGES...
- Slightly cooler today, then temperatures climbing well above
  normal for Thursday through the weekend.
- Isolated to scattered shower and thunderstorm chances
  (~20-40%) return for early next week.
&&
.SHORT TERM...
Issued 222 PM CDT Wed Oct 1 2025
Tonight through Thursday night:
The ridge over the central and eastern CONUS will remain through
the rest of the week and into the weekend. While the ridge
remains in place some weak vorticity maxima will shift across
south central Wisconsin today into Thursday which will keep
upper level clouds around. These upper level clouds will be
moving in from the southwest leading to partly cloudy skies.
Sfc high pressure southeast of James Bay will slowly meander
southeast toward Cape Cod. All of which gives us dry and quiet
conditions.
Patterson
&&
.LONG TERM...
Issued 222 PM CDT Wed Oct 1 2025
Friday through Wednesday:
The upper level ridge will strengthen heading into Friday and
Saturday and the sfc high that was once near James Bay will
meander along the Atlantic states. Southerly winds and warm air
advection will be well underway with temps climbing day by day.
Friday and Saturday will be the warmest days of the forecast
period with highs in the upper 80s. Its not out of the question
for a few locations to have highs hit 90. The best potential
for any 90 degree days will be mostly limited to the WI/IL
boarder areas. Will be keeping an eye on temps for both of these
days as we will be near record highs.
The summer like pattern looks to begin breaking down across the
Great Lakes Region Sunday into Monday. An upper level ridge will
dig down from Canada and a mid level trough should swing across
the Rockies Saturday. The mid level trough in the Rockies is
expected to lift northeast into the Northern Plains by Sunday
and will eventually merge with the trough to the north in
Canada on Monday. While this trough is moving through the upper
level ridge that was in place looks to shift southwestward into
the Southern Plains and remain. The sfc low will follow a very
similar path as the mid level, moving northeast across the
Rockies and into the Northern Plains. The center of the sfc low
will pass to the northwest of Wisconsin. The trough and sfc low
will continue northeast and eventually drag a cold front
through the state Sunday night into Monday. As the front moves
into Wisconsin, it will be weakening and slowing down. The loss
of good lift along the frontal boundary has limited our
precipitation chances and dropped the chances run after run to
where we sit now around 10-25%. Regardless of if we get
precipitation or not, this should bring some reprieve from the
temps in the upper 80s. Heading into mid week there is another
trough that swings down from Canada into the Great Lakes
Region. This will bring another slight better chance for rain
late Monday night into Tuesday around 30-40%. This active
pattern looks to persist further into the extended with
additional shortwaves moving through the upper level steering
flow. There remains a lot of uncertainty here on the exact path
of these shortwaves so its possible that we may trend drier as
the days go on, especially if the ridge to our south looks to
win out.
Patterson
&&
.AVIATION...
Issued 222 PM CDT Wed Oct 1 2025
VFR conditions are expected through the period. Upper level
clouds will continue to stream in from the southwest today.
Southeast winds will continue through tonight and become
southerly Thursday.
Patterson
&&
.MARINE...
Issued 222 PM CDT Wed Oct 1 2025
East winds today will become southeast tonight and increase. The
breezy southeast winds tonight into Thursday morning will cause
waves to build in the nearshore which will result in Small Craft
conditions. Thus a Small Craft Advisory is in effect late
tonight into Thursday afternoon when waves finally subside.
Meanwhile high pressure will slide south to southeast from James
Bay into the New England States Thursday. This high will
continue down the eastern seaboard through the end of the week.
Winds will shift to southerly Thursday and remain into the
weekend.
A broad low pressure will form over the northern Great Plains
Saturday, and will gradually attempt to work toward the upper
Mississippi River Valley by the end of the weekend. Chances for
isolated showers and thunderstorms return to the forecast early
next week.
Patterson
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645...3 AM Thursday to
     3 PM Thursday.
&&
$$
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NWS MKX Office Area Forecast Discussion