NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 201651
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1051 AM CST Tue Jan 20 2026
.KEY MESSAGES...
- Wind chills in the teens below zero are expected to continue
into this morning.
- A Heavy Freezing Spray Warning remains in effect through this
morning.
- A Winter Weather Advisory is in effect from 9 PM CST this
evening until 6 AM CST Wednesday morning, mainly along and
south of the Highway 18 and Interstate 94 corridor. Snow
accumulations of 2 to 5 inches are expected, with locally
higher amounts near the Illinois border area. Snow covered and
slippery roads are expected.
- Another Arctic cold front will push east through the area
later Wednesday into Wednesday evening, bringing the
possibility of locally heavy and fast moving snow showers. The
best chances would be southwest and south of Madison. These
snow showers may greatly reduce visibility quickly and cause
hazardous driving conditions.
- Bitter cold temperatures and wind chills are likely Thursday
night into the weekend.
&&
.UPDATE...
Issued 1045 AM CST Tue Jan 20 2026
No major changes in the forecast thus far though I have ticked
down snow ratios and QPF, primarily because while the DGZ may be
deep the forcing in the DGZ is not overly strong and there are
some gusty winds in the highest portions of the DGZ. As for QPF
the tick down is largely due to a slight ticked down in the QPF
from the CAMs. In either case the snow looks largely expected to
impact the southern 2 tiers of counties in the CWA.
In addition, expect another quick round of accumulating snow
late Wednesday afternoon through the early evening.
Kuroski
&&
.SHORT TERM...
Issued 428 AM CST Tue Jan 20 2026
Today through Wednesday night:
Light west winds and temperatures in the single digits below
zero will continue to support wind chills in the teens below
zero across the area into the morning hours. Winds will shift
southwest this afternoon and bring highs into the teens above
zero with some weak warm air advection. Clouds will gradually
shift into the area later in the day.
A Winter Weather Advisory is in effect from 9 PM CST this
evening until 6 AM CST Wednesday morning, mainly along and south
of the Highway 18 and Interstate 94 corridor. Models continue to
show low pressure shifting east northeast across far northern
Illinois later tonight, with the 850 mb low level jet nose
pointing northeastward into the Wisconsin/Illinois border area.
This area will also see focused warm air advection and a band of
850 mb to 700 mb frontogenesis response develop this evening and
linger overnight. Forecast soundings are generally showing
fairly deep saturation within the dendrite snow growth zone
tapping into the upward vertical motion.
Thus, models have a swath of QPF moving across far southern
Wisconsin and the Wisconsin/Illinois border area tonight,
exiting Wednesday morning. Snowfall rates from the HREF are
generally one quarter to one half inch per hour south, lower to
the north. The frontogenesis band may certainly have enhanced
snowfall rates of up to 1 inch per hour, depending on where
exactly it will set up. There is still uncertainty with where
this band will occur.
There is enough confidence in a general 2 to 5 inch snowfall in
the southern half of the area to issue the Winter Weather
Advisory. Lower amounts are expected further to the north. Snow
covered and slippery roads are expected, and the tail end of
this event may affect the early morning commute on Wednesday.
Further refinements of the heavier swath of snow are
anticipated, which may shift a little further north or south of
the current forecast.
The snow should taper off west to east by the end of the
advisory period, with a temporary lull in the snow activity.
Another Arctic cold front will then shift east across the area
later Wednesday afternoon into Wednesday evening. This front
will have gusty winds along and behind it, with forecast
soundings showing saturated and steep low level lapse rates in
the dendrite snow growth zone.
The snow squall parameter on the NAM is 3 to 5, with the GFS 1
to 2.5 during this period, with anything over 1 favorable for
snow squalls. At the very least, locally heavy and quick moving
snow showers may occur in this setup, with snow squall
potential. This would bring greatly reduced visibility in a
short period of time, leading to hazardous driving conditions. A
quick inch of snowfall may occur as well, with the gusty winds
perhaps bringing some blowing snow. Will continue to monitor
this potential.
West winds with cold air advection behind the front will bring
lows into the single digits above zero Wednesday night, with
wind chills in the single digits below zero.
Wood
&&
.LONG TERM...
Issued 428 AM CST Tue Jan 20 2026
Thursday through Monday:
Synopsis: Settling in behind Wednesday evening/night's frontal
passage, a renewed surge of Arctic air will move into the
western Great Lakes from north central Canada during the
Thursday to Friday time frame. It continues to appear that said
Arctic air will bring the coldest air of the season-to-date,
and perhaps the last several years, to southern Wisconsin
through the end of the week. The Thursday night to Sunday time
frame will thus be a period to monitor for cold weather
headlines in coming forecasts.
Deterministic forecasts from the global guidance suite hint at
some additional chances for snow Thursday night into Friday, and
once again Saturday evening, though their ensemble-based
counterparts are drier in both time periods, due to placement
uncertainties regarding responsible forcing mechanisms. Will
continue to monitor trends and provide additional details
should greater agreement on snow during the Thursday night into
Friday and/or later Saturday time periods become more
apparent.
Thursday through Sunday: A prolonged stretch of bitterly cold
to at times dangerous cold is on track to settle into southern
Wisconsin. Deterministic forecasts continue to depict an area of
25 below to 30 below zero Fahrenheit 850 mb temps moving into
the region from northern Canada, with the core of the Arctic air
mass settling overhead Thursday night through Sunday morning.
Ensemble-based statistics illustrate the highly anomalous nature
of the incoming air mass, with both the ECMWF and GEFS
indicating 850 mb temperatures in the 0.5th to 1st percentile of
model climatology from Thursday night through Saturday night.
If said percentiles are mapped to the underlying temp/wind chill
distributions driving the NBM, they would translate to
overnight wind chills near or below Extreme Cold Warning (30
below zero or colder) thresholds both Thursday night into
Friday and Friday night into Saturday across most of southern
Wisconsin, with additional periods of Cold Weather Advisory
conditions (20 below zero or colder) extending into Sunday.
Will continue to be watching trends through the end of the week
to see where wind chill forecasts ultimately settle. Regardless
of where minimum wind chills ultimately line up, anticipate some
sort of cold weather headlines through this part of the period.
If possible, try to limit time outdoors. If necessary, dress in
plenty of layers and limit exposed skin if needing to be
outside.
Quigley
&&
.AVIATION...
Issued 1050 AM CST Tue Jan 20 2026
Light west winds will shift southwest this afternoon. Middle to
high clouds will move in this afternoon ahead of this next
system
Snow is expected to spread into the area this evening,
generally over most of the area by 03Z to 04Z Wednesday. The
snow will continue overnight before ending from west to east by
around 12Z Wednesday. Winds will be light during the snow
tonight into early Wednesday morning.
Snowfall rates generally around one quarter to one half inch
per hour are expected over most of the area, perhaps lower
toward Sheboygan. There is a heavier west to east snow band that
will set up, with rates of up to 1 inch per hour, but there
remains uncertainty with where it will occur and how
focused/narrow that band will be. A general 2 to 5 inch
snowfall is expected in the southern half of the area, with
lower amounts to the north. Fluffy, powdery snow character is
expected.
Ceilings should be in the 800 to 1300 foot AGL range during the
period of snow tonight into early Wednesday morning, with
visibility generally in the 1 to 2 mile range. It may drop to
around 1/2 mile within heavier snow bands.
Another round of snow expected late Wednesday afternoon through
the early evening with another half inch up to 2 inches expected
with temporary VSBY reductions in snow to around a half mile
with and another period of at least MVFR CIGS possible.
Kuroski
&&
.MARINE...
Issued 428 AM CST Tue Jan 20 2026
High pressure around 30.6 inches well southeast of the region
will shift east today. Gusty west winds this morning will shift
west southwest this afternoon. Elevated waves and Arctic air
will continue to lead to areas of heavy freezing spray through
this morning. A Heavy Freezing Spray Warning remains in effect
until Noon CST today for all of Lake Michigan.
West to southwest winds will continue tonight, with low
pressure around 29.8 inches moving across southern Lake Michigan
Wednesday morning. West winds are expected behind the low
Wednesday afternoon.
Winds will increase further and shift west to northwest
Wednesday night, as another Arctic cold front crosses Lake
Michigan. A few gale force gusts may occur. Gusty west to
northwest winds Thursday will will turn mainly northwest Friday,
as strong high pressure around 30.9 inches builds into the
northern Great Plains. A few gale force gusts may occur during
this period.
Winds may reach Small Craft Advisory levels across the nearshore
waters of Lake Michigan at times Wednesday night into Friday
night.
Arriving Arctic air and elevated wave heights will support
additional periods of moderate to potentially heavy freezing
spray Wednesday night into Friday night.
Wood
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory...WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-
WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...9 PM Tuesday
to 6 AM Wednesday.
LM...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.
&&
$$
Visit us at weather.gov/milwaukee
Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee