NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 181637
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1037 AM CST Sun Jan 18 2026
.KEY MESSAGES...
- A Winter Weather Advisory is in effect from the mid to late
afternoon today 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 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 23 to 29 below zero are expected during this
period. Wind chills in the teens below zero are 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.
&&
.UPDATE...
Issued 1030 AM CST Sun Jan 18 2026
Confidence in areas of blowing snow late tonight into Monday
morning has increased, and a Winter Weather Advisory has been
issued. The decision was made to include the light (1 to 2 inch)
powdery snow accumulations occurring this afternoon / evening in
the Advisory for sake of completeness, though the early phase
of the event is generally of lesser concern.
Similar to our last snowfall event, very powdery / dry snow
texture this afternoon and evening, with light to occasionally
moderate snowfall rates. Some of those elevated rates may occur
during the arctic cold front passage this evening.
30 to 40 MPH northwest wind gusts arrive around midnight (just
after midnight further east) and cause the light / powdery snow
to blow and drift, leading to reduced visibility and slick
spots. Winds begin to subside towards mid day Monday, allowing
the blowing snow to subside.
The majority of the impacts with this event will affect Monday
AM travel (blowing snow phase of the event), though some more
marginal impacts with the light accumulating snowfall later this
afternoon / evening are possible as well.
Sheppard
&&
.SHORT TERM...
Issued 421 AM CST Sun Jan 18 2026
Today through Monday night:
There is still some pesky flurry activity lingering in eastern
parts of the area early this morning, as one last area of weak
differential CVA pushes through with moist low levels in the
dendrite snow growth zone. This activity should push off to the
east by sunrise. There may be some pockets of clearing at times
into this morning, before more clouds move in by midday as warm
air advection develops.
Models are still in good agreement with a period of light snow
moving east southeast through southern Wisconsin this afternoon
into this evening, exiting to the east/northeast later tonight.
This is being driven by a passing Arctic cold front this
evening, with some low level frontogenesis response ahead of and
behind it and some differential CVA from a shortwave trough
passing just south of the area. Forecast soundings are saturated
in a deep layer with the dendrite snow growth zone tapped in the
low levels.
Look for the snow to move east into the area by middle
afternoon, peaking late afternoon and early evening, then
gradually exiting from west to east late evening into the
overnight hours. Snowfall rates should be up to one quarter
inch per hour, so a steady, light snow is expected. Snow to
liquid ratios will be around 20 to 1 or so, with one to two
inches of fluffy accumulation expected.
Strong cold air advection on gusty northwest winds are expected
after the Arctic cold front moves through. This may cause some
blowing and drifting snow, given the fluffy nature of the new
snow, as well as recent snowfall that probably has not
compacted much. Some visibility reductions may occur, as well as
some drifting on north to south roads. Will need to monitor if
this will be a more widespread issue in later forecasts.
The cold air advection will bring much colder temperatures and
wind chills into the area later tonight into Monday night. Lows
should drop into the single digits below zero over most of the
area, with wind chills in the 23 to 29 below zero range late
tonight into Monday morning. A Cold Weather Advisory is in
effect for the entire area during this period. Fairly confident
wind chills will not drop to the 30 below zero or colder
thresholds at this time.
Wind chills should remain in the teens below zero Monday
afternoon into Tuesday morning, with gusty west northwest winds
and temperatures in the single digits above zero Monday
afternoon, with lows Monday night in the single digits below
zero.
Wood
&&
.LONG TERM...
Issued 421 AM CST Sun Jan 18 2026
Tuesday through Saturday:
Synopsis: Mean upper troughing will continue to linger from the
Hudson Bay into the western Great Lakes through the duration of
the long term period. Given the persistent synoptic pattern,
southern Wisconsin will remain favorably positioned for impacts
from clipper systems, with attendant surface cold frontal
passages bringing additional bouts of very cold temperatures and
wind chills.
Tuesday evening into Wednesday is currently favored for the
most widespread snow potential across the area, with some signal
for accumulation in probabilistic forecast guidance. Low level
winds will turn northwesterly behind the Tuesday evening and
Wednesday system, with chilly temperatures and wind chills
settling in for the Wednesday night through Thursday time frame.
Signals for another clipper system are evident during the
Friday to Saturday time period, though high uncertainty remains
regarding wintry precipitation potential in southern Wisconsin.
Of greater confidence, however, is that another pull of Arctic
air will sag into the western Great Lakes with the affiliated
clipper system during the Friday-Saturday time period.
Additional very chilly temperatures and wind chills are thus
anticipated from the end of the upcoming work week into next
weekend.
Tuesday Night through Wednesday: Expect the next best chances
for widespread snowfall during this time frame. Snow will
initially focus along bands of 1000-700 mb frontogenesis & warm
advection Tuesday night through early Wednesday, with activity
trending more scattered in nature into Wednesday afternoon as a
cold front moves east of the area and cold advection becomes
predominant. Probabilistic forecasts from global ensemble
guidance and the NBM indicate some potential for accumulation,
though confidence in probabilities at any given location are
low, due to lingering north-south dispersion regarding system
track between ensemble members. Will continue to monitor trends
and offer additional details as track trends clarify in coming
forecasts.
Wednesday Night through Thursday: Expect another round of
chilly temps and wind chills as Arctic air re-establishes over
the western Great Lakes. Have maintained temperature and wind
chill forecasts from the NBM, which would keep conditions a
touch milder than Cold Weather Advisory criteria. Any colder
shifts, however, would push wind chills toward headline
thresholds during the Wednesday night through Thursday morning
period. Will thus be closely monitoring trends over coming
forecasts.
Thursday Night through Saturday: Guidance suggests that another
disturbance will cross the region, with possible phasing
between multiple areas of upper forcing making precipitation
chances more uncertain relative to Tuesday night into Wednesday.
Regardless of whether/not precip occurs, there is a much
stronger signal for another surge of Arctic air to make it into
the area along/behind the passing system. If current forecasts
from the NBM verify, this next Arctic surge could be even colder
than the one expected during the Wednesday night-Thursday
period. Will thus be monitoring for possible cold weather
headlines as this part of the period pulls closer.
Quigley
&&
.AVIATION...
Issued 1030 AM CST Sun Jan 18 2026
Low clouds have cleared out, leaving a brief window of VFR through
the rest of the morning into much of the early afternoon. The
current scattered to broken high altitude clouds will thicken and
decrease in altitude this afternoon, with predominantly MVFR
ceilings later this afternoon through tonight, scattering out into
Monday morning. Light to briefly moderate accumulating snow is
expected to approach from the west this afternoon, overspreading the
whole region by around 6 PM CST today, tapering off late this
evening into tonight. Roughly 1 to 2 inches of additional snow
expected. Expecting the existing light southwesterly breeze to
continue throughout today, with a lull ahead of an approaching
cold front early this evening.
An arctic cold front sweeps across the region this evening (perhaps
leading to a brief intensification of the aforementioned snowfall as
it passes), with gusty northwest winds behind it. Wind gusts upwards
of 30 kt will lead to areas of blowing snow late tonight into Monday
morning, with pockets of reduced visibility.
Sheppard
&&
.MARINE...
Issued 421 AM CST Sun Jan 18 2026
Low pressure around 29.8 inches will move from northwest
Minnesota this morning to the eastern Upper Peninsula of
Michigan today. West to southwest winds are expected today
across Lake Michigan.
The low will then strengthen to around 29.5 inches as is shifts
into eastern Ontario tonight, and into Quebec on Monday. An
Arctic cold front will move across the lake later this evening,
with northwest gales and heavy freezing spray expected behind
the front later tonight through Monday afternoon.
A Gale Warning is in effect for all of Lake Michigan later
tonight through Monday afternoon. A Gale Warning is in effect
for the nearshore waters of Lake Michigan later tonight through
Monday morning. A Small Craft Advisory will be needed Monday
afternoon and evening for lingering gusty northwest winds.
The strong winds will combine with building waves and cold
temperatures to bring heavy freezing spray later tonight through
Tuesday morning. A Heavy Freezing Spray Warning is in effect
during this period across all of Lake Michigan. Some freezing
spray is possible in the nearshore waters, mainly toward the
open waters.
High pressure around 30.5 inches will shift from the northern
Plains into the Lower Mississippi River Valley Tuesday, with
winds across Lake Michigan shifting west to southwest.
Wood
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory...WIZ046-WIZ047-WIZ056-WIZ057-WIZ062-
WIZ063-WIZ067-WIZ068-WIZ069...3 PM Sunday to 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.
Winter Weather Advisory...WIZ051-WIZ052-WIZ058-WIZ059-WIZ060-
WIZ064-WIZ065-WIZ066-WIZ070-WIZ071-WIZ072...6 PM Sunday
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...midnight
Monday to 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...midnight Monday to noon Tuesday.
Gale Warning...LMZ643-LMZ644-LMZ645-LMZ646...midnight Monday
to noon Monday.
&&
$$
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