NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 180243
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
843 PM CST Sat Jan 17 2026
.KEY MESSAGES...
- Winter Weather Advisory remains in effect until 9 PM in
southeast Wisconsin.
- Below normal temperatures are expected this weekend through
the early part of next week. The coldest temperatures and wind
chills are expected Sunday night through Tuesday. We are
expected to reach Cold Weather Advisory criteria (wind chills
20 degrees below zero) Sunday night into Monday morning.
- Light accumulating snow is expected Sunday afternoon into
Sunday night, with new accumulations around 1 to 2 inches
across the region. Gusty northwest winds Sunday night into
Monday may lead to some areas of blowing snow. Watch for
slick spots and pockets of reduced visibility.
- A Gale Watch is in effect for Lake Michigan late Sunday night
through Monday, with a Heavy Freezing Spray Watch late Sunday
night through mid day Tuesday.
&&
.UPDATE...
Issued 840 PM CST Sat Jan 17 2026
Forecast remains largely on track this evening. Steady snows
have concluded across the western half of the area, where the
Winter Weather Advisory was allowed to expire at 6 PM CST.
Further east, steady snows continue, albeit at tapering hourly
rates. Activity is ongoing within a band of 925-850 mb
frontogenesis & warm advection, with model analyses from the RAP
showing the forcing & most favorable DGZ depths shifting
southeast. Said shifts likely explain the tapering rates in
east-central and southeast Wisconsin. Expect these trends to
continue near-term, with the remainder of the Winter Weather
Advisory on track to expire at 9 PM CST.
Further west, a pronounced surface ridge is evident from
Minnesota into the Missouri Valley. Light radar returns are
apparent along the leading periphery of the ridge, and are
likely being driven cold advection & weak frontogenesis at the
925 mb level. Have noted reports of flurries within these
echoes, though reports have been sporadic as dew points fall
into the single digits along the leading edge of the ridge. Have
reflected these trends in the near term grids (now through 1
AM) with 10-30% precip probs, with the expectation that
arriving very dry air will shut activity off during the predawn
hours. Will continue to monitor trends and make adjustments if
necessary. Not anticipating impacts in any flurry activity
through the late evening hours.
Quigley
&&
.SHORT TERM...
Issued 320 PM CST Sat Jan 17 2026
Tonight and Sunday:
Surface to 850mb FGEN continues to drive some light to moderate
accumulating snow across southern WI this afternoon. A Winter
Weather Advisory remains in effect into this evening for
portions of the region, expiring in a west to east manner, with
additional accumulations up to around 1 to 1.5 inches and
short periods of 1/2 mile visibility. As seen in the surface
wind fields, a gradual re-centering of the FGEN (and associated
moderate snow rates) to far southeastern WI is expected (and
ongoing based off of 3:20 PM radar composite images), moving out
over Lake Michigan by around 9 PM CST this evening. Some off/on
flurries may linger for several hours after the accumulating
snow ends.
Dry weather is expected late tonight into Sunday morning, with
another batch of accumulating snowfall from Sunday afternoon
into Sunday night. Totals around 1 to 2 inches expected with
this second batch. Winds and gusts should remain less than or
equal to 20 MPH through the daytime hours of Sunday, with
daytime high temperatures in the mid to upper teens expected. As
such, the wind chill temperatures should be in the single digits
above/below zero through much of this timeframe. That all
changes late Sunday night as the arctic front arrives.
Sheppard
&&
.LONG TERM...
Issued 320 PM CST Sat Jan 17 2026
Sunday night through Saturday:
A fairly strong shortwave trough will quickly swing sewd from the
Dakotas to the MS River by 00Z Mon, then across srn WI and nrn IL
Sun evening. Cyclogenesis will be ongoing over the nrn Great Lakes
during this time with the trailing arctic front to move across srn
WI as well. Weak low to mid level warm advection will give way to
PVA, low to mid level frontogenesis, and cold advection with the
strong arctic front. QPF values of 0.10 inches or less are
forecast with high liquid to snow ratios yielding 1-2 inches.
The greater concern is the increasing wind fields late Sun nt
into Mon AM and blowing snow potential. Nwly wind gusts of 35-40
mph and several inches of powdery snow depth may necessitate a
Winter Wx Advisory for blowing snow. In addition, A Cold Weather
Advisory will likely be needed as early as Mon AM as wind chill
temps plummet to 20 below to 29 below zero, while air temps
plummet to 5 below zero to 3 above zero by sunrise Mon AM. The
Cold Weather Advisory would continue at least through the morning
but may be needed through the day and into Mon nt. This will
be due to air temps only rising to 2-6 above zero for the day
while brisk winds continue.
The winds will become light for late Mon nt and Tue when a weak
sfc ridge moves across srn WI. A series of shortwave troughs in
nwly flow aloft will then traverse the region into Thu. A round of
swly winds and warm advection ahead of one of the upper waves may
bring likely (60% chance) snows to srn WI for Tue nt lingering
into Wed. For late in the week the jet stream attempts to return
to zonal flow with warm advection bringing 20 percent chances for
light snow. Polar to arctic air will remain over srn WI for much
of the week.
Gehring
&&
.AVIATION...
Issued 840 PM CST Sat Jan 17 2026
Largely MVFR flight categories prevail this evening as -SN
begins to taper across southern Wisconsin. Expect reduced flight
categories to continue into the overnight hours. Will be
monitoring light flurries currently being reported to the west
of I-39 for possible additions through the late evening hours.
High pressure will move into the region closer to daybreak,
resulting in weakening winds. Whether the high's arrival will
bring VFR conditions remains uncertain. Have brought VFR flight
categories into the forecast at KMSN and KJVL, and maintained
MVFR categories further east. Will continue to monitor trends. The
high will move east tomorrow afternoon, allowing southwest
winds to become established. Another disturbance is forecast to
move into the western Great Lakes later tomorrow afternoon and
evening, bringing additional chances for -SN to all terminals
nearing the end of the period. Will continue to refine -SN
mentions in the coming 03Z and 06Z updates.
Quigley
&&
.MARINE...
Issued 320 PM CST Sat Jan 17 2026
Low pressure around 29.7 inches will continue to move away across
southern Quebec tonight with a trailing cold front moving across
Lake Michigan. Modest to brisk west to northwest winds are
expected.
Another low pressure system around 29.9 inches will track from
northwest Minnesota Sunday morning to slowly across the northern
Great Lakes through Monday and deepen to 29.6 inches as it does
so. An arctic front will then move across the lake early Monday
morning with northwest gales and heavy freezing spray possible. A
Gale Watch is in effect for all of Lake Michigan from early Monday
morning and through the day. A Heavy Freezing Spray Watch is in
effect from early Monday morning through Tuesday morning. Westerly
winds will then gradually weaken Monday night and Tuesday.
Gehring
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory...WIZ059-WIZ060-WIZ064-WIZ065-WIZ066-
WIZ069-WIZ070-WIZ071-WIZ072 until 9 PM Saturday.
LM...Gale Watch...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 Watch...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 Watch...LMZ643-LMZ644-LMZ645-LMZ646...midnight Monday to
noon Monday.
&&
$$
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