NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 231805
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
105 PM CDT Mon Mar 23 2026

.KEY MESSAGES...

- High pressure moves in today with temperatures around normal.

- Chances (mainly 20 to 30 percent) for precipitation returns to
  the area for Thursday. Potential for a few thunderstorms as
  well.

&&

.SHORT TERM...
Issued 100 PM CDT Mon Mar 23 2026

Tonight through Wednesday night:

Modest south to southeast winds tonight behind a lake breeze as
the high pressure shifts east of CWA tonight into the mid Great
Lakes region. A front will also be pushing into the region
overnight with the best forcing and deep moisture off to the
north but some WAA, perhaps some weak shortwave activity aloft
with moisture between 500-700mb there will be some potential for
precip to fight their way to the surface. However, dry air is
largely expected to win out tonight as the surface to 800mb
layer looks quite dry and with such a brief period of moisture
aloft the period to see that layer moisten up is short thus
making precip unlikely but I have included some chances for a
few flurries overnight into early Tuesday morning.

Tuesday/Tuesday night looks largely quiet as high pressure
largely wins out but winds remain southerly with developing low
pressure out to the west. Moisture aloft will be present likely
bringing a mostly cloudy day. Any precip Tuesday night into
Wednesday will remain well north associated with the warm front
from the low pressure system to the west. Into Wednesday some
models bring some light chances for a shower across far eastern
WI but the lack of moisture in most models suggests these
chances are limited. If moisture in future models runs increases
across various models Wednesday, there will be sufficient WAA
to at least allow for some light showers/drizzle. By Wednesday
night, expect drier conditions to return as the mid to upper
levels largely dry out.

Kuroski

&&

.LONG TERM...
Issued 100 PM CDT Mon Mar 23 2026

Thursday through Tuesday:

Synopsis: West-northwest upper level winds will persist across the
western Great Lakes through the period, with a lack of pronounced
mid-level waves leaving precipitation chances confined to surface
frontal passages. The first of two cold fronts remains forecast to
cross southern Wisconsin during the day on Thursday, bringing rain
areawide with a few thunderstorms possible near the Wisconsin-
Illinois border. Noticeably cooler conditions will prevail behind
the departed front Friday into Saturday, with highs 5-10 degrees
below normal on Friday afternoon. Temperatures will gradually
rebound from the second half of the weekend through the start of
next week. The next cold front will move into Northern Plains-
western Great Lakes vicinity next Monday, though its arrival &
affiliated precipitation chances will likely hold off until just
beyond the end of the current long term period.

Thursday: The best precip chances of the current long term period
arrive along a passing cold front. Very mild conditions in place
ahead of the front---current guidance suggests the potential for
highs 10-15+ degrees above normal---will be supportive for all rain
during the frontal passage. Whether any convection can mix in with
the rain will depend upon the precise timing of the cold frontal
passage, with available guidance showing a range of morning or
afternoon timings. A later/slower solution would allow more time for
instability to work toward southern Wisconsin, introducing some
potential for embedded thunderstorms. At present, said slower/later
solution remains less favored amongst available guidance, so the
forecast has been trended toward all rain & no thunder in the mid-
day update. Will nevertheless be monitoring trends, particularly
along & south of the I-94 & US-18 Corridors, where the best
potential for thunderstorms would exist in the event of a slower
cold frontal passage. A much drier air mass will quickly work into
southern Wisconsin behind the cold front by Thursday evening, with
the expectation that precipitation will shut off before any
changeover to appreciable snowfall can materialize. Can nevertheless
rule out a few wet snowflakes mixing in with rain as precip vacates
during the late afternoon/early evening hours.

Thursday night through Saturday: A strong push of cold advection
will lead to seasonably chilly conditions, particularly through
Friday afternoon. Will see a blustery start to the day Friday, with
wind chills forecast to fall into the teens by daybreak. Expect
highs in the low-mid 40s away from Lake Michigan Friday afternoon,
with readings remaining in the mid-upper 30s closer to Lake
Michigan. Gradual improvements will occur during the day Saturday.

Quigley

&&

.AVIATION...
Issued 100 PM CDT Mon Mar 23 2026

VFR conditions expected in the TAF period with high pressure
pushing through tonight. Lighter and winds turning from north to
east and then back to south from today into tonight. Primarily
southwest winds through the rest of the TAF period with largely
high clouds tonight through Tuesday but some breaks in the
clouds would be expected. No major concerns in the TAF period.

Kuroski

&&

.MARINE...
Issued 100 PM CDT Mon Mar 23 2026

Low pressure of 29.6 inches off the coast of Maine will continue
east as high pressure of 30.5 inches in the Northern Plains
pushes toward and builds into Michigan. The pressure gradient
is gradually weakening between these two systems which will
bring an end to the gusty winds over the next few hours as the
high builds in. Light and variable winds are expected into this
evening as the high moves overhead.

However, into the late overnight hours and into Tuesday winds
in the north half of the lake may become breezy as a stalling
front moves over the north side of the lake behind the departing
high. This may actually bring south winds that may approach
gales although gales remain unlikely at this time. This will
however bring a brief window of chance Tuesday morning for small
craft conditions over the northern tiers of the nearshore
waters. Winds are currently expected to remain just below small
craft thresholds. Winds will weaken through Tuesday as the front
weakens and high pressure to the north squeezes out the stronger
pressure gradient to the east.

Largely south winds remain through Wednesday, as a broad low
pressure around 29.8 inches approaches from the west. Chances
for precipitation on Tuesday and again on Wednesday though
primarily for northern parts of the lake.

The next best chance for gales will come Thursday evening as the
backside of a low pressure system around 29.6 inches works
southeast.

Kuroski

&&

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

&&

$$

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