NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 190326
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
926 PM CST Sun Jan 18 2026

.KEY MESSAGES...

- A Winter Weather Advisory remains in effect through Monday
  morning. Light accumulating snowfall is expected this
  afternoon and evening, with totals around 1 to 2 inches. Gusty
  northwest winds late tonight into Monday morning will then
  lead to areas of blowing and drifting snow. Slick spots on
  pavement and periods of reduced visibility are expected.

- A Cold Weather Advisory is in effect late tonight through
  Monday morning across all of southern Wisconsin. Bitter cold
  wind chills of 22 to 29 below zero are expected during this
  period. Wind chills of 10 to 20 below zero are then expected
  Monday afternoon into Tuesday morning.

- A Gale Warning is in effect for all of Lake Michigan later
  tonight through Monday afternoon. A Heavy Freezing Spray
  Warning is in effect as well later tonight through Tuesday
  morning.

- Accumulating snow is looking likely (55-70% chances) Tuesday
  night into Wednesday.

- Polar to arctic air (cold temperatures) will prevail through
  this week and next weekend.

&&

.UPDATE...
Issued 930 PM CST Sun Jan 18 2026

Regional radar shows continuing light to occasionally moderate
snow over the eastern half of the area this evening. Said area
of snow is being driven by weak warm advection near the 925 mb
level. A gap in precipitation is apparent over central portions
of the CWA, which is aligned with the approximate position of
the advancing Arctic cold front. 9 PM analyses show the boundary
extending along a line from roughly Stevens Point to Madison to
Platteville. Deep cold advection is ongoing to the west of the
front, which is helping to trigger additional snow showers
toward the La Crosse vicinity. The Arctic front & trailing snow
showers will continue to advance east through the rest of the
evening hours, bringing plummeting temperatures and wind chills
for the second half of the overnight hours. Accumulation will be
light in additional snow showers, though the light/powdery
character of recent snows and very gusty winds will contribute
to blowing snow & potential travel impacts into Monday morning
across southern Wisconsin. Have thus maintained the Winter
Weather Advisory as-is this evening. Budget extra travel time
if planning to be on the roads.

The 3 AM CST onset time of the Cold Weather Advisory remains on
track this evening, with no upward/earlier adjustments in
beginning times anticipated. Will, however, be monitoring
minimum wind chill trends in western zones, as a few locations
could see chills drop to near or just below -30 from the predawn
hours through daybreak (~3-7 AM). Best potential for a few -30
or colder readings would be roughly along & west of a Monroe-
Madison-Ripon line, where probabilistic guidance depicts ~20%
chances for wind chills at or just below -30 during the 3-7 AM
time period. Current expectation is that any such conditions (if
they occur at all) would be isolated & short enough in duration
to preclude the need for Extreme Cold Warnings. Will
nevertheless be monitoring trends and coordinating with
neighboring offices if necessary through tonight. Regardless of
how low wind chills get in your location, bundle up if heading
outdoors late tonight through Monday morning. Dress in layers,
and try to minimize any areas of exposed skin.

Quigley

&&

.SHORT TERM...
Issued 315 PM CST Sun Jan 18 2026

Tonight through Monday night:

Light accumulating snow has begun to fall across the region, and
our best guess is that the expected 1 to 2 inch totals (now thru
late this evening) are generally on track. We wouldn't be too
surprised to see some slightly higher totals in a few spots
given how high the snow-to-liquid ratios are with this extremely
powdery / fluffy snow. Generally seeing visibility dropouts to
around 2 miles at times, with brief periods of around 1/2 mile.
The Winter Weather Advisory does cover this phase of the event,
but the primary window of "Advisory level conditions" will
actually occur after the snow winds down late tonight.

An arctic cold front crosses the region this evening, with
strong northwest winds (30 to 40 MPH gusts) behind it. These
gusty winds, arriving around or after midnight tonight, will
lead to areas of blowing and drifting snow. Broken low-altitude
clouds will linger tonight and tomorrow morning and could even
produce a few flurries, but the main story will be the bitter
cold wind chills (air temps around or just below zero, wind
chills of 22 to 29 below zero), slick spots on pavement due to
drifting snow, and areas of reduced visibility due to blowing
snow. All of these are expected to impact AM travel, hence we
have both a Winter Weather Advisory and Cold Weather Advisory in
effect. Both are set to expire mid day Monday as the northwest
winds begin to gradually decelerate.

Dry weather expected Monday and Monday night. Daytime high temps
in the single digits above zero, lows in the single digits
below zero. Wind chills through this period will be 10 to 20
below zero.

Sheppard

&&

.LONG TERM...
Issued 315 PM CST Sun Jan 18 2026

Tuesday through Sunday:

Polar or arctic air will prevail during this period.

A weak surface ridge will pass Tue into early Tue evening with
cold temps continuing. A shortwave trough will then track from the
nrn high plains to srn WI and nrn IL by 12Z Wed. A wave of low
pressure will accompany this feature and track across nrn IL into
lower MI with some differences on this track among the models. A
nose of 50 kt low level jet will support low to mid level warm
advection and frontogenesis supported aloft by PVA and warm
advection at the jet level. A narrow west to east band of several
inches of snow will be possible whether its in srn WI or nrn IL.
Areas of light snow may then linger into Wed.

Modest cyclogenesis will be underway over the nrn Great Lakes for
Wed-Wed nt while another shortwave trough approaches from the nw
and tracks across srn WI Wed nt along with a wave of low pressure
and cold front. These features also differ in strength among the
models with only small chances for light snow forecast at this
time, but trending higher. Wly winds and cold advection will
continue into Thu.

From Thu into Fri a large upper low will move into wrn Ontario
from central Canada then shift ewd into Quebec. It trailing
trough axis will force a strong arctic front across srn WI Thu nt
with frigid conditions to follow. A 1045 mb high may shift ewd
across the region Fri nt-Sat with a lingering sfc ridge into Sat
nt. This frigid air mass will likely be the coldest of the season
and possibly in years. Stay tuned!

Gehring

&&

.AVIATION...
Issued 930 PM CST Sun Jan 18 2026

Mix of flight categories currently prevails as SN continues
across the region. A strong Arctic front remains on track to
cross southern Wisconsin tonight, bringing a gusty northwest
wind shift and additional periods of -SN. Precip will conclude
during the predawn hours, though gusty winds will support
continued BLSN impacts into Monday morning at all terminals.
BLSN impacts will gradually subside Monday afternoon as high
pressure moves in from the Northern Plains and winds begin to
weaken.

Quigley

&&

.MARINE...
Issued 330 PM CST Sun Jan 18 2026

Low pressure will deepen to 29.5 inches over the northern Great
Lakes by sunrise Monday and sweep an arctic front across the lake
after midnight tonight. Northwest gales will develop and last
through Monday afternoon with a Gale Warning in effect, while a
Heavy Freezing Spray Warning will also go into effect and last
through Tuesday morning.

High pressure around 30.5 inches will shift across the southern
and eastern portion of the country for Tuesday into Wednesday,
supporting modest west to southwest winds over Lake Michigan.
A couple more cold frontal passages will bring a return of brisk
west to northwest winds for later Wednesday through Friday.
Heavy freezing spray may also return.

Gehring

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-
     WIZ057-WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-
     WIZ066-WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072 until
     noon Monday.

     Cold Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-
     WIZ057-WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-
     WIZ066-WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...3 AM
     Monday to noon Monday.

LM...Gale Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
     LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
     LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until 6 PM
     Monday.

     Heavy Freezing Spray Warning...LMZ080-LMZ261-LMZ362-LMZ364-
     LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
     LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
     until noon Tuesday.

     Gale Warning...LMZ643-LMZ644-LMZ645-LMZ646 until noon Monday.

&&

$$

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