NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 030014
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
614 PM CST Mon Mar 2 2026

.KEY MESSAGES...

- Light rain chances (about 20 to 45 percent) return later
  tonight through Tuesday morning. Some light freezing
  drizzle/rain or light snow could briefly mix in before 9 AM
  Tuesday (when temperatures rise), though widespread impacts
  aren't currently anticipated. Highest precip chances are south
  of a Wisconsin Dells to Watertown to Kenosha line, though some
  north-south shift remains possible.

- A warming trend Tuesday through the end of the week.

- Additional periods of rain are forecast Wednesday into
  Thursday (about 30 to 70 percent chances) and Friday into
  Saturday (about 75 to 90 percent chances). Some thunderstorms
  are possible in each round of rain.

&&

.UPDATE...
Issued 610 PM CST Mon Mar 2 2026

Forecast remains largely on track early this evening, with minor
updates being recently made to account for latest cloud cover &
temp/dew point trends. Largest near-term forecast challenge
continues to be the potential band of light precipitation late
tonight into early Tuesday morning. Regional radar mosaics show
the beginning of said precipitation from eastern South Dakota
into northwest Iowa, where an area of upper divergence &
attendant 850-700 mb frontogenesis are providing sufficient lift
for a narrow band of rainfall. Expect this area of precipitation
to continue shifting eastward this evening & tonight as the
responsible forcing mechanisms move toward southern Lake
Michigan. Do expect some contraction in precipitation coverage
as this occurs, as activity will be encountering progressively
drier air that remains in the wake of departed high pressure.
Thus anticipate that any precip will be confined to the
immediate vicinity of the low level frontogenesis and upper
divergence by the time it reaches southern Wisconsin early
Tuesday morning (~4-10 AM), with precip struggling to reach the
ground elsewhere. Previous expectations for track of the best
lift remain generally on track, but will be closely monitoring
for potential north-south wobbles as the evening guidance suite
comes in. Still can't rule out some light freezing drizzle or
snow at the outset of precipitation, and will be closely
monitoring trends through this evening.

Quigley

&&

.SHORT TERM...
Issued 135 PM CST Mon Mar 2 2026

Tonight and Tuesday:

An arc of low stratus clouds will gradually push eastward from
southeastern MN / eastern IA, reaching south-central WI then
eroding through this evening. High clouds approach and gradually
thicken tonight, holding overnight low temperatures close to the
freezing mark. Our forecast calls for surface air temps
bottoming out a few degrees below freezing, though right at
freezing or ~1 degree above freezing temps are also possible
depending on how quickly clouds arrive and inhibit radiational
cooling.

A WNW to ESE oriented band of 850-700mb frontogenesis will track
eastward across our region from 3 AM to Noon CST Tuesday,
delivering 20-45% precip chances (which are highest south of a
Wisconsin Dells to Watertown to Kenosha line). Though precip
will only last for a few hours off/on in any given area, there
will be a window (before 9 AM CST Tuesday) for wintry
precipitation to mix in, either light freezing rain or light
snow. The snow would be of minimal concern, and practically
wouldn't accumulate at all, but there is potential for a very
thin glaze of ice from the light freezing rain / drizzle.
Both the forecast air temperatures and precip 'chances' leave in
question whether this thin glaze of ice would be able to form,
it may boil down to whether or not pavement temperatures are
cold enough in any given area. Eastern and east-central WI have
drier air throughout the column during the event (hence the
lower end of the precip chances, around 20%) and may fail to
observe any measurable precip at all.

Though clouds do linger into Tuesday afternoon before scattering
apart, temperatures manage to climb to the 40s (upper 40s for
some inland areas, low 40s by the shoreline), with light and
variable winds.

Sheppard

&&

.LONG TERM...
Issued 135 PM CST Mon Mar 2 2026

Tuesday night through Monday:

Weak low pressure developing over the central Great Plains will
work with departed high pressure (offshore of the northeastern
CONUS) on Tuesday to develop a warm front spanning from the
middle Mississippi River Valley through Ohio on Tuesday. The
aforementioned low tracks northeastward along it's warm front,
tracking just to the south of our region Wednesday and leading
to some 15-30% rain chances (highest further south). These
rain chances ramp up (50-70%) late Wednesday night into
Thursday as the low intensifies and tracks past the southern tip
of Lake Michigan. A few rumbles of thunder cannot be completely
ruled out (less than 25% chance though, thus not present in our
forecast grids), but any convection would be elevated based on
our positioning north of the warm front. A slight lull in the
rain chances unfolds Thursday night.

Both Wednesday and Thursday feature above normal temperatures,
with inland daytime highs in the upper 40s to low 50s, likely
cooler towards the lakeshore.

A much more organized Colorado low pressure tracks northeastward
across our region later this week, with high rain chances
(70-90%) Friday into Friday night. The exact track of this low
remains uncertain, there's potential for it to track roughly
overhead, delivering high temps in the mid to upper 50s, or
alternatively track across far northern portions of the state
and deliver highs in the 60s. Both of these tracks come with
moderate rainfall, but the northern track would put us in the
warm sector, significantly boosting thunderstorm chances. As
such, we'll be watching trends in the system track closely.

A lull in this active weather pattern is possible this weekend,
specifically later Saturday into Sunday. Our best guess is for
the CAA on the back side of the departing low pressure to be
weak, leaving temperatures above normal. A separate low
pressure system tracking eastward across central Canada into
Sunday may allow WAA to briefly resume early next week before
temperatures return closer to seasonal norms.

Sheppard

&&

.AVIATION...
Issued 610 PM CST Mon Mar 2 2026

VFR flight categories prevail through the first half of this
evening at southern Wisconsin terminals. Already being observed
in the vicinity of MSN, low-mid level overcast will gradually
work east through the predawn hours as an upper disturbance
approaches from the west. Expect eventual MVFR flight categories
at all aerodromes by mid-morning Tuesday, with reductions slowly
arriving from southwest to northeast as dry low level air
lingers behind departing high pressure. Aforementioned low level
dry air makes any prevailing IFR outside of precipitation
uncertain, and has motivated a continued MVFR forecast in the
00Z update. Any such precipitation is likely to focus along a
relatively narrow band of lift in the low-mid levels, with
forecast guidance still split over the precise track of said
lift. Have thus inserted PROB30 groups at all terminals in the
00Z update given location uncertainties, and will elevate to
TEMPO and/or prevailing groups as forecast trends clarify into
this evening. Still could see some brief -FZDZ or -SN at the
outset of precipitation with temperatures lingering near
freezing, with a changeover to all rain quickly occurring after
sunrise Tuesday. Any precip will conclude by mid-morning
Tuesday, with dry conditions prevailing through the remainder of
the period. Anticipate a return to prevailing VFR flight
categories Tuesday afternoon at all aerodromes.

Quigley

&&

.MARINE...
Issued 135 PM CST Mon Mar 2 2026

Low pressure around 29.5 inches will move east into Hudson Bay
today, with high pressure around 30.6 inches moving east through
the northeastern CONUS. This will drive breezy south to southeast
winds across Lake Michigan today, particularly over the northern
third of the lake where gusts to 30 knots are possible. Winds will
subside tonight into Tuesday as both pressure systems depart
eastward, with light and variable winds Tuesday afternoon through
Tuesday night.

Light east to northeast winds develop into Wednesday as weak low
pressure around 29.9 inches develops over the central Great
Plains, tracking northeastward through the middle Mississippi
River Valley. The low will approach and ultimately pass near or
just south of the southern portions of the lake Wednesday night
into Thursday. East to northeast winds will linger. Periods of
rain will accompany the low Wednesday into Thursday, with a few
thunderstorms possible over southern Lake Michigan Wednesday
afternoon and evening.

Another low pressure system around 29.5 inches will form in the
central Great Plains Thursday night, and is forecast to progress
toward the Upper Mississippi River Valley during the day on
Friday. The approach of the low will bring increasing southerly
winds to the open waters on Friday, along with widespread areas of
rain and embedded thunderstorms.

The low will move northeast across the region and into Ontario
Friday night through Saturday, dragging a cold front across Lake
Michigan in the process. Additional rain is expected during the
frontal passage. Winds will veer southwest to west as the front
passes.

Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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