831
FXUS63 KMKX 280225 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
925 PM CDT Wed Aug 27 2025

.KEY MESSAGES...

- Scattered showers and a few thunderstorms are expected mainly
  overnight into Thursday morning, as a cold front shifts south
  through the area.

- An isolated shower or thunderstorm (20 percent chance or
  less) may linger to Thursday afternoon.

- A period of dry and fair weather is forecast for Friday into
  early next week. Temperatures will be several degrees below
  normal values into this weekend.

&&

.UPDATE...
Issued 925 PM CDT Wed Aug 27 2025

One area of showers and a few storms were noted from far
southern Minnesota and northeast Iowa into far southwest
Wisconsin. This was associated with some low level warm air
advection and a low level jet nose pointing into that area. This
activity should continue to shift southeast into the area
overnight.

Another area of showers and a few storms were noted over
northern Wisconsin into the Upper Peninsula of Michigan, along
and ahead of a southward-moving cold front and 500 mb shortwave
trough. These features are expected to shift south into the area
overnight and through the area by early to middle afternoon on
Thursday.

Thus, scattered showers (30 to 50 percent) with at least a few
storms remain forecast overnight into Thursday morning. These
may need some adjusting upwards, if the upward vertical motion
remains strong enough to maintain more widespread rain showers.
Not sure if any fog will develop overnight in south central
Wisconsin, given the front moving toward and through the area.

The storms will not have much mean layer CAPE to work with, as
it remains skinny and generally under a few hundred J/kg.
Chances will decrease in the afternoon, though a stray shower or
storms may linger before drier air starts to push into the area
behind the cold front. Highs in the lower to middle 70s are
forecast ahead of the front on Thursday.

Winds will shift northeast behind the cold front Thursday
afternoon and weaken somewhat Thursday night, as high pressure
moves into the region from the north. Most clouds should clear
out Thursday night, with cool low temperatures in the middle to
upper 40s expected inland.

Wood

&&

.SHORT TERM...
Issued 310 PM CDT Wed Aug 27 2025

Tonight through Thursday night:

Though some isolated shower activity (currently evident over
eastern IA / southern MN) associated with low to mid level WAA
may push eastward into the region this evening, shower and weak
storm coverage is expected to remain isolated until after
midnight tonight, when the cold front sags southward into the
region. Scattered to numerous pop up showers and weak
(disorganized) thunderstorms will then continue through Thursday
morning, likely becoming isolated after 10 AM CDT. Instability
for a lingering isolated storm will remain present into the
afternoon, though models resolve little to no activity. Lapse
rates decline and instability vanishes into the evening, leaving
dry weather from then onwards.

Sheppard

&&

.LONG TERM...
Issued 310 PM CDT Wed Aug 27 2025

Friday through Tuesday:

Dry weather expected to dominate this forecast period as high
pressure remains over the Upper Great Lakes region. A light
northeast breeze does continue into Friday, but remains slow enough
over Lake Michigan to allow wave heights to decline throughout
Friday morning, likely allowing any lingering Small Craft / Beach
Hazards to subside by late morning. Friday is expected to be the
coolest day, with highs in the upper 60s to around 70 degrees flat.
Afterwards, temperatures slowly moderate back up to the mid 70s by
early next week. With late-August climatological norms in the upper
70s for Madison and Milwaukee, these temperatures would still be
considered `a few degrees below normal`.

Light and variable winds underneath the high pressure system coupled
with overnight periods of clear or mostly clear skies will likely
allow several rounds of radiation fog to develop in low lying marshy
areas and river valleys late each night / early each morning,
burning off soon after sunrise. This would be most prevalent at
inland areas (away from Lake Michigan) given how warm the water
temperatures currently are. Overnight lows in the mid to upper 40s
expected Friday night (50s near the Lake Michigan shoreline due to
continued weak onshore flow), gradually moderating up to the 50s
into early next week.

Kept precip chances under 10% through the weekend and early next
week, but towards the middle of next week, high pressure retreats
just far enough east and model certainty in the jet pattern drops
low enough to merit some 15-30% precip chances mid week. Nothing
definitive yet. Similarly, there is solid spread in the temperature
forecast beyond mid next week, but below average temperatures
continue to be the favored solution, along with relatively quiet
weather.

Sheppard

&&

.AVIATION...
Issued 925 PM CDT Wed Aug 27 2025

One area of showers and a few storms with ceilings around 6000
feet AGL were noted from far southern Minnesota and northeast
Iowa into far southwest Wisconsin. This activity should continue
to shift southeast into the area overnight.

Another area of showers and a few storms with ceilings around
5000 feet AGL were noted over northern Wisconsin into the Upper
Peninsula of Michigan, along and ahead of a southward-moving
cold front. These features are expected to shift south into the
area overnight and through the area by early to middle afternoon
on Thursday.

Thus, scattered showers with at least a few storms remain
forecast overnight into Thursday morning. May leave PROB30
groups for all terminals for now, until better timing can be
determined. The precipitation may need more prevailing wording
at terminals, if the upward vertical motion remains strong
enough to maintain more widespread rain showers. Not sure if any
fog will develop overnight in south central Wisconsin, given
the front moving toward and through the area. Ceilings may drop
to below 2000 feet AGL later tonight into Thursday morning.

Chances will decrease Thursday afternoon, though a stray shower
or storms may linger before drier air starts to push into the
area behind the cold front.

Modest southwest winds ahead of the front will shift northeast
and become gusty for a time behind it Thursday afternoon. These
winds should weaken somewhat Thursday night, as high pressure
moves into the region from the north. Most ceilings should clear
out Thursday night.

Wood

&&

.MARINE...
Issued 925 PM CDT Wed Aug 27 2025

A trough of low pressure and associated cold front will drop
southward through the region overnight into early Thursday.
Southwest winds will continue ahead of the cold front, veering
due north to northeast behind it. The passing front will likely
produce scattered showers and isolated thunderstorms, with some
potential for waterspouts overnight over the northern and
eastern portions of the lake, then over the southern and
eastern portions of the lake Thursday.

North winds behind the cold front become breezy Thursday
afternoon and evening, then gradually subside into Friday, as
high pressure around 30.1 inches builds into the region from the
north. An extended period of light and variable winds with
quiet weather will then occur this weekend through early next
week, as high pressure around 30.2 inches lingers over the upper
Great Lakes.

Sheppard/Wood

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066-WIZ071-
     WIZ072...noon Thursday to 7 AM Friday.

LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...noon
     Thursday to 7 AM Friday.

&&

$$

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