NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 221147
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
647 AM CDT Sun Mar 22 2026

.KEY MESSAGES...

- Some chances (around 10-20 percent) for light rain to occur
  later tonight into Sunday morning. Cooler temperatures and
  gusty winds are expected Sunday morning.

- There will be a few, intermittent gusts to gale force over the
  southern half of Lake Michigan this morning into the evening.

- Chances (mainly 20 to 30 percent) for precipitation returns to
  the area for middle to later portions of next week.

&&

.UPDATE...
Issued 647 AM CDT Sun Mar 22 2026

Breezy north to northeast winds have set up across southern
Wisconsin now that sfc cold front is just south of the state
border. Light rain has set up across central Wisconsin this
morning along an access of mid level moisture and 700mb Fgen.
Guidance continues to suggest that this mid level lift will move
south with time, but that the rain will become more scattered to
isolated as it moves through southern Wisconsin. Forecast
soundings that have the rain completely dissipating show the mid
levels drying out. Current dewpoint depressions of 5 to 10
degrees or more are also detrimental to the rain chances. Kept
POPS around 10 to 15% as this 700mb Fgen moves south as there is
still a chance for some drizzle or patchy light rain, but it
wont be nearly as organized as it is right now to our north. If
the mid level forcing is slow to shift south, it is possible
that temperatures cool enough to compensate for this slight
drier air, but confidence on this occuring is very low. Either
way the amount of rain we will see will be low.

Patterson

&&

.SHORT TERM...
Issued 1141 PM CDT Sat Mar 21 2026

Today through Monday Night:

A cold front is currently angled across the state from Prairie
du Chien to Manitowoc. The front will continue to sag south
through tonight, bringing breezy north winds behind it as cold
advection brings a more seasonable air mass back to the area.
850-700mb fgen looks to be the main driver of lift with any
precip along the front, but RAP and HRRR model soundings show a
lot of dry air from the 900 to 600 mb level. As a result, precip
should struggle as it moves into our area. Still, a few
sprinkles and light showers may saturate the low to mid-levels
enough for light precip to make it to the surface over central
tonight, and then along the WI/IL border late Sunday morning
into the afternoon. With the cold advection, highs will be in
the low to upper 40s tomorrow across the area. Overnight lows
will dip back down into the 20s amid clearing skies.

High pressure moves in for Monday with daytime cu and similar
highs to Sunday across the area.

CMiller

&&

.LONG TERM...
Issued 1158 PM CDT Sat Mar 21 2026

Tuesday through Saturday:

High pressure lingers on Tuesday as ridging builds aloft over
the plains and southwesterly winds return. Highs will begin to
rebound into the 50s, though warm advection over the region will
kick off more cloud cover.

Precipitation chances are then expected to begin Midweek as
temperatures continue to warm and a frontal boundary parks over
the Middle Mississippi Valley region on Wednesday, with a wave
propagating along the boundary on Thursday. At this time,
Wednesday's precipitation chances look to be driven by some
nebulous warm advection, with the NBM broadly splashing PoPs of
20% across the state, given disagreement among the global
models. Thursday, the wave looks a bit stronger but consistency
in location is lacking, so 20 to 30% PoPs have been maintained.
The GFS does produce some skinny CAPE profiles on Thursday, so
any precip, especially along the WI/IL border may feature
thunder.

Following Thursday's wave, cold air pushes back into the area
with temperatures moderating back toward normal to slightly
below normal Friday and Saturday.

CMiller

&&

.AVIATION...
Issued 647 AM CDT Sun Mar 22 2026

VFR to MVFR conditions are expected through the period. MVFR
ceilings around 1-3 kft will be possible this morning into the
afternoon as light rain moves south through the area. The
scattered to isolated rain will be very light and boarding on
drizzle. Rain chances are low around 10-15% as dry air will also
be battling the precipitation as it moves through. Thus rain has
been kept out of the TAFs. Ceilings will improve this evening
into tonight as high pressure builds in.

Breezy north to northeast winds this morning will remain
through this evening. As high pressure builds in tonight winds
will weak and become more variable heading into Monday morning.

Patterson

&&

.MARINE...
Issued 1126 PM CDT Sat Mar 21 2026

Low pressure will push east across the lake tonight. As this
low passes southeast of the lake, winds will shift to the north
and northeast and become gusty into Sunday morning. A few,
sporadic northerly gales are possible Sunday, mainly over
southern portions of the lake. High pressure should then bring
decreasing winds for Monday through Monday night. Into Tuesday
winds may pick up a bit from the south as the high exits and
weak front passes over the region. Winds over the lake will
remain largely from the south through Wednesday as broad low
pressure approaches from the west. Chances for precipitation on
Tuesday and again on Wednesday though primarily for northern
parts of the lake.

CMiller

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 1 AM
     Monday.

&&

$$

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