NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 100243 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
843 PM CST Sun Nov 9 2025

.KEY MESSAGES...

- Winter Weather Advisory remains in effect for accumulating
  heavy snow in far southeastern Wisconsin late this evening and
  overnight. If the snow band spreads further inland than
  currently forecast, or lingers longer over the Advisory area
  than expected, cannot rule out locally higher amounts and
  additional headline changes would be needed.

- Moderate to heavy snow rates of 1 inch per hour will be
  possible and impacts to travel are expected, and may linger
  into the Monday morning commute.

- Cold temperatures in the teens and 20s tonight, with wind
  chills in the lower teens and single digits above zero.

- Temperatures return to near normal mid-week and are trending
  above normal for the end of the week.

&&

.UPDATE...
Issued 843 PM CST Sun Nov 9 2025

No changes at this time to the Winter Weather Advisory for the
lake effect snow band affecting far southeast Milwaukee County,
and eastern Racine and Kenosha Counties, late this evening and
overnight. The latest HRRR continues to be the most aggressive
with bringing the single lake effect snow band onshore in the
far southeast by 05Z to 06Z, perhaps affecting the lakeshore
counties to the north, lingering overnight before pushing
southeast.

The rest of the CAMs are focusing this band on the far
southeast areas overnight for a few hours before shifting
southeast, with a few keeping it just offshore. The HRRR,
despite being the most aggressive, still has the far southeast
with the most impacts from the snow band overnight. Given these
trends and recent radar imagery, will leave the current Winter
Weather Advisory going for now.

If the band does push a little more inland or affects more of
the lakeshore counties, and the residence time of the band over
the southeast counties is greater than 4 to 5 hours, then
adjustments to the headlines and snowfall amounts will be
needed. For now, 1 inch per hour or greater rates are still
possible with this band, with a very favorable setup and
instability over the lake. Will continue to monitor the progress
of the lake effect snow band and make adjustments as needed late
this evening and overnight.

Wood

&&

.SHORT TERM...
Issued 301 PM CST Sun Nov 9 2025

Tonight through Monday:

Overview:
An upper-level trough will continue dig down across the Upper-
Great Lakes region tonight. This strong dynamically forcing
paired with northerly flow over Lake Superior and Lake Michigan
along with an Arctic airmass over the region (850mb temps vs
lake Michigan water temps is around a 20C difference) is setting
a pattern conducive for lake effect setup. Already have been
seeing periodic bands set up over the Great Lakes today bringing
moderate to heavy snows to Door county in WI as well as
northern IN and southwest Michigan. Global models as well as the
hi-res/CAMs continue to pick up on another mid-lake band
developing across Lake Michigan later this evening and overnight
as the winds turn north/northeasterly. There is a consistent
trend since yesterday for this band to waffle far enough
westward to clip far southeastern WI and bring several inches of
accumulating snow along with an hourly snow rate around 1
inch/hour. Greatest confidence in seeing these high snowfall
amount are for far southern Milwaukee, eastern Racine, and
eastern Kenosha counties. Thus have issued a Winter Weather
Advisory for these area for 2-5 inches into Monday morning.

Winds are expected to shift more northerly into Monday morning
and the lake effect band will follow suite and migrate around
the southern tip of Lake Michigan through the day and chances
will diminish across southern WI through the day.

While the focus is on the lake effect snow, cannot forget about
the cold temps in the teens to mid 20s overnight. Inland areas
may also experience teens to single digit winds chills with the
gusty northerly winds lingering overnight. Luckily temps warm
back up above freezing for Monday behind this system.

Lake Effect Snow:
While there is high enough confidence for this band of lake
effect snow to impact southeastern WI to issue a Winter Weather
Advisory, there are still a few questions and uncertainty with
an event like this. Lake effect snow bands are always difficult
given minor mesoscale details can alter an outcome drastically.
A 10 degree wind shift or a shift in the band by 10 miles may
keep the lake effect band offshore, thus keeping southeastern WI
dry. Only the NAM and a few members of the REFS group continue
to show this scenario. However, the majority of the HREF members
as well as the GFS, RAP, ECMWF, and CMC all depict it clipping
southeastern WI.

On the other hand there are some hints, especially in some of
the hi- res models (a few recent runs of the HRRR and the RAP)
that actually bring this band further inland, thus could see
higher amounts exceeding 6 inches along the lakeshore and 3-5
inches spread further inland. Also with this scenario could see
snow accumulations further north up into Ozaukee and Sheboygan
counties as well. While not out of the question, do not have
high enough confidence in this scenario at this time, but will
bear watching.

Another question is how long will the lake effect band sit over
southeastern WI. Most models given it at least a 3hr to 8hr
window and thus the longer the increased snowfall amounts,
especially given the potential for higher hourly snowfall rates
to 1"/hr or even higher. So the longer it sits over the area the
higher snowfall we are expecting.

Overall, despite the uncertainty and lingering questions, there
is enough evidence to support southeastern WI to be impacted by
this band overnight and linger into Monday morning. Thus a
Winter Weather Advisory has been issued from 7PM tonight until
6AM Monday Morning. One last note is to pay attention the
forecast this evening because as we go through the evening and
see how the Lake Effect Snow band develops, it will answer some
of the aforementioned questions/uncertainties above. So while
there is potential for this lake effect band to overperform
compared to models and see snow rates greater than 1"/hr and
snowfall exceeding 6 inches, really want to see the whites of
its eye before jumping into an upgrade at this time because it
can just as easily underperform and end up sitting just offshore
missing southeastern WI. Thus pay attention, especially if you
live in and around these areas as expansion as well as an
upgrade to the headline is not out of the question in a few
hours from now.

Wagner

&&

.LONG TERM...
Issued 301 PM CST Sun Nov 9 2025

Monday night through Sunday:

With the upper-level trough to the east of the area Monday
night will allow for quieter, cool night with the northern
fringes of high pressure as it skirts southeastward from the
Plains into southeastern US. Winds then begin to turn more
southerly into Tuesday ahead of an upper-level shortwave trough.
Will see temps warm back into the 40s during the afternoon.
Then as the trough begins to dig across the Upper Midwest, the
associated surface low is progged to traverse across Ontario
later Tuesday into Wednesday and drag a cold front down across
WI.

Ahead and along this frontal boundary looks to be our next
window for precip chances. Surface forcing paired with ample
low-level WAA as well as nose of 35-45kt LLJ will be enough to
support a swath of precip across southern WI through the day.
While in a warmer pattern, most model continue to project this
activity to fall as snow given the cold environment aloft, but a
wintry may be possible at times as well, especially if the NAM
model sounding trends ends up materializing. So Tuesday will be
our next window to monitor as could pick a few inches of
accumulating snow.

Then cold front swings through overnight and drier airmass
settles into the area for Wednesday. While northwesterly flow
sets up over the area into Wednesday, not expecting too much of
a drop in temps as upper-level ridging continually builds
across the central CONUS through the end of the week. Expecting
temps to gradually be warmer each day Thursday through Saturday
as this upper-level ridge builds over the region. Continue to
see increased probabilities (>50%) of well above normal temps
with daily highs in the 50s and even creeping into the 60s by
the weekend. Then the pattern looks to become more active toward
the second half of the weekend into early next week as the
upper- level ridge flattens and shift east.

Wagner

&&

.AVIATION...
Issued 843 PM CST Sun Nov 9 2025

The single lake effect snow band should move into the Kenosha
and Milwaukee terminals by 05Z to 06Z or so, lingering
overnight before moving to the southeast by 09Z to 12Z Monday.
Snowfall rates of 1 inch or more per hour are possible in this
band, and a wet, slushy snow is expected.

Locally reduced visibility to 1 mile or less and ceilings of
1000 feet AGL or less in the most intense bands. Would expect a
general 2 to 5 mile visibility with ceilings of 1500 to 2500
feet AGL with the lake effect snow. Gusty north northwest winds
are expected overnight here as well, which may lead to some
blowing snow.

Elsewhere across the area, some light snow showers or flurries
may affect Waukesha and Sheboygan for a few more hours.
Otherwise, VFR ceilings have cleared out of Madison and this
trend should gradually spread to most terminals away from Lake
Michigan overnight. Gusty north northwest winds are expected
here as well.

Ceilings should end across the lakeshore terminals Monday
morning, with gusty northwest winds expected across the area
through the day. Should see some middle to high clouds move in
Monday evening, with winds shifting west and weakening.

Wood

&&

.MARINE...
Issued 843 PM CST Sun Nov 9 2025

Gusty northerly winds will persist overnight between high
pressure over the Northern Plains and low pressure lifting
through the northeast United States. A Gale Warning remains in
effect overnight across the southern half of the lake.

A waterspout or two is not out of the question into Monday, as
a significant lake effect snow is expected along with the
passage of a trough. Winds will remain gusty Monday as the high
shifts southeast and the low continues to lift northeast, with a
few gale force gusts possible again across the south half of
the lake.

A Small Craft Advisory remains in effect into Monday evening for
the nearshore waters, and may need to be extended into Wednesday
or Wednesday night for continued gusty winds.

Winds will become southwest on Tuesday. Winds may hit gale
force yet again Tuesday into Wednesday in the south, between a
trough and high pressure over the southeast United States. Gusty
conditions will linger into Wednesday, with lighter winds
possible Thursday as high pressure moves through the region.

DDV/Wood

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory...WIZ066-WIZ071-WIZ072 until 6 AM
     Monday.

LM...Gale Warning...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
     LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until 6 AM
     Monday.

     Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 9 PM
     Monday.

&&

$$

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