NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 151832
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
132 PM CDT Sun Mar 15 2026
.KEY MESSAGES...
- Significant icing impacts are likely mainly north of I-94
through late afternoon. Ice accumulations up to a quarter inch
are possible, with locally higher amounts. Lighter ice totals
up to a tenth of an inch are possible through the evening
hours along and south of I-94.
- The wintry mix of precipitation will transition to moderate to
heavy snowfall from northwest to southeast through this
afternoon and early evening, with snow then persisting tonight
through Monday morning. Near blizzard conditions are possible
tonight into Monday, especially north and west of Madison.
Expect significant impacts to the Monday morning commute.
- A few thunderstorms remain possible through this afternoon to
the south of I-94, with some gusty winds small hail possible.
- A Gale Warning, Storm Warning, and Heavy Freezing Spray
Warning are in effect for varying periods through Tuesday
morning.
- Light accumulating snowfall may impact the Wednesday morning
commute.
&&
.SHORT TERM...
Issued 132 PM CDT Sun Mar 15 2026
Tonight through Monday night:
Widespread precipitation will continue this afternoon, as
deepening low pressure heads east across northern Illinois. The
low has trended a bit farther south and temps at the surface and
aloft have wound up colder than anticipated today. This has
resulted in higher icing impacts from freezing rain north of
I-94, which will continue through the afternoon, lingering into
early evening in the northeast. Precip type may hang on as all
snow in the far northwest forecast area the rest of today, with
mainly rain south of I-94 this afternoon.
Low pressure will continue to deepen as it lifts northeast over
southern Lake Michigan this evening. The slowing/lifting of the
low will result in a gradual transition from rain and mixed
precip to all snow northwest to southeast later this afternoon
through early this evening. Increased ice totals a bit south of
I-94 for late afternoon and early evening as the freezing rain
potential may linger a bit longer than anticipated earlier. The
transition line between mixed precip and all snow should clear
the far southeast by midnight, with snow then persisting
overnight into Monday morning.
Another noteworthy change with this system is that models have
trended back upward with with the deformation precip on the
backside of the surface low mid evening into Monday morning.
There will be plenty of forcing from top to bottom, given upper
level divergence, a strong vortmax at 500 mb, and ample mid
level frontogenesis. There is a dry slot upstream, but looks
likely this could fill in fairly quickly based on the bulk of
12Z mesoscale models. Bumped up forecast precip totals during
this period, winding up close to the HREF values, while still a
little under some of the higher models such as the 12Z HRRR and
GFS runs.
Still expecting strong winds on the back side of the deepening
low this evening into Monday, which will cause increasing
blowing and drifting snow concerns from northwest to southeast
as the snow begins to pile up. Model soundings continue to show
gusts to 40-50 mph in the mixed layer overnight into Monday
morning, with gradually decreasing winds Monday afternoon into
the evening. Kept snow to liquid ratios in the 10-13 to 1 range
due to the fact that the strong winds will greatly reduce
ratios, despite the falling temps and solid forcing within the
dendrite growth zone.
The snow should wind down tomorrow from southwest to northeast
late morning into late afternoon. Even with decreasing snowfall
rates, the lingering strong winds during the day tomorrow will
likely result in continued impacts from blowing and drifting
across the forecast area into late afternoon. Will maintain the
winter weather headline expiration times of 4 pm CDT tomorrow
for now, though could see this get pushed a couple hours later
across the northeast forecast area as models have slowed a tad
with the exiting of the accumulating snow and lingering
blowing/drifting snow concerns. Given the potential light icing
farther southeast as well as snow totals inching upward and
lingering blowing snow concerns tomorrow, leaning towards
expanding the Winter Storm Warning a bit farther eastward.
DDV
&&
.LONG TERM...
Issued 132 PM CDT Sun Mar 15 2026
Tuesday through Sunday:
A surface ridge is expected to build into the area Tuesday morning
as the center of a high pressure system sinks south into the
middle Mississippi River Valley. Morning temperatures will be in
the low single digits and rise to the teens by noon. With some
modestly breezy conditions hanging on in the morning, wind chills
will hang out around zero until midday. High temperatures for the
day are expected to be in the low 20s, which will be about 20
degrees below normal for this time of the year.
Heading into Tuesday night, a clipper system is expected to move
southeast toward the state, primarily driven by a weak 500mb
shortwave as well as some 850 to 700mb fgen and WAA. At this time
the GFS and ECMWF ensembles favor areas southwest of Madison for
at least an inch of snow assuming a 10:1 ratio. The GFS has 1 inch
at 50 to 70% probs, while the ECMWF is lower at 30 to 50%. Both
hold negligible probs for over 3 inches. Current timing has the
snow coming in just after the evening rush southwest of Madison,
reducing Tuesday evening travel impacts.
Snow ends Wednesday morning and warm advection will push
temperatures to highs near 40 with weak high pressure moving
across the state. Wednesday night into Thursday, solutions diverge
a bit regarding precipitation potential, as the GFS favors dry
conditions into the weekend, while the ECMWF brings a trough and
light mixed precip through Wednesday night into Thursday. At this
time, the NBM only favors 15% to 20% PoPs given the model
disagreement.
Heading into the upcoming weekend, a ridge is expected to build
over the plains. We'll begin to warm back to above normal
temperatures as warm advection kicks in over the upper Midwest
and a baroclinic zone sets up from the central Dakotas to the
eastern Corn Belt.
CMiller
&&
.AVIATION...
Issued 132 PM CDT Sun Mar 15 2026
Widespread precipitation will remain over southern Wisconsin
through today, tonight and the first half of tomorrow. Currently
rain is occurring over southeast WI for KUES, KMKE and KENW and
along the WI/IL border for KJVL. Northward, freezing surface
temperatures have allowed for freezing rain/sleet and snow at
times along and northwest of a line from KMSN to KSBM.
Ceilings are expected to decrease to IFR and LIFR everywhere
this afternoon as the surface low passes to our south and cold air
gradually works south and east. The intrusion of colder air will
change freezing rain areas to snow and rain areas to
sleet/freezing rain, then all snow much later into tonight. Vis is
expected to be restricted as these precip types change and then
be severely limited as snow begins and ramps up. Snowfall rates
will be moderate to heavy with gusts from 35 to 40 knots causing
near whiteout conditions at times. Moderate to heavy snow will
continue overnight into tomorrow morning before tapering off
toward 18Z Monday. BLSN will likely linger into Monday afternoon
after the snow ends as winds will remain elevated and blow over
the fresh snowpack.
CMiller
&&
.MARINE...
Issued 132 PM CDT Sun Mar 15 2026
Low pressure of 29.3 inches will approach the southern end of
Lake Michigan this afternoon, and pass over the southern end of
the lake by midnight CDT tonight. Currently, northwest gales are
ongoing over the northern third of the Lake, while a warm front
bisects the lake and causes weaker winds from midlake,
southward. A Gale Warning continues over all of the lake at this
time.
As the surface low lifts north- northeast into Lower Michigan
state, gales are expected to shift southward down the lake as
winds become northwesterly over the more of the lake and fetch
improves. The strong pressure gradient over the lake will allow
for very strong winds gusts over roughly the northern half of the
lake and storm force winds are anticipated from this evening into
Monday afternoon. A Storm Warning is in effect over the northern
half of the lake. Along with the high winds, colder air moving
over the lake will support heavy freezing spray over the whole
lake Monday Morning into Tuesday, and a Heavy Freezing Spray
Warning has been issued for this time frame.
Monday, northwest winds will turn northerly and northwesterly,
continuing to support storm force gusts into the afternoon. Winds
should drop below storm force criteria late Monday afternoon and
remain high end gales into Monday evening. While the Gale Warning
drops off of the northern half of the lake Monday night, this
segment may need to be extended, as models suggest gales may
continue over the northern half of the lake until the pre-dawn
hours of Tuesday.
Northwest winds then ease Tuesday morning as the surface low pulls
way and surface high pressure of 30.3 inches approaches the lake.
Additionally, visibility will be heavily restricted over the lake
as heavy snow moves over northern portions of Lake Michigan today,
and then all of the lake tonight into tomorrow morning.
CMiller
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory...WIZ059-WIZ062-WIZ063 until 7 PM
Sunday.
Winter Storm Warning...WIZ059-WIZ062-WIZ063-WIZ064-WIZ067-
WIZ068-WIZ069...7 PM Sunday to 4 PM Monday.
Winter Storm Warning...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-
WIZ057-WIZ058 until 4 PM Monday.
Winter Weather Advisory...WIZ060 until 4 PM Monday.
Winter Weather Advisory...WIZ065-WIZ066-WIZ070-WIZ071-
WIZ072...10 PM Sunday to 4 PM Monday.
LM...Gale Warning...LMZ080-LMZ673-LMZ675-LMZ777-LMZ779-LMZ874-
LMZ876-LMZ878 until 7 AM Tuesday.
Heavy Freezing Spray Warning...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ643-LMZ644-LMZ645-LMZ646-
LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878...4 AM Monday to 11 AM
Tuesday.
Gale Warning...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ868-LMZ870-LMZ872 until 7 PM
Sunday.
Storm Warning...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ868-LMZ870-LMZ872...7 PM Sunday
to 10 PM Monday.
Gale Warning...LMZ643-LMZ644-LMZ645-LMZ646 until 1 AM Tuesday.
&&
$$
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