NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 050402
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1102 PM CDT Mon May 4 2026

.KEY MESSAGES...

- Cooler temperatures are expected for the rest of the week.

- Frost may occur each night away from Lake Michigan Tuesday
  night into Thursday night.

&&

.SHORT TERM...
Issued 1102 PM CDT Mon May 4 2026

Overnight through Wednesday night:

Lingering gusty west northwest winds should gradually weaken
overnight. One area of middle to high clouds will shift east of
the area, with another area moving in overnight and into Tuesday
morning. This should settle more in the southern/southeastern
portions of the area, where some 700 mb to 500 mb frontogenesis
response may remain. This may bring some sprinkles or isolated
light showers overnight. Lows should drop into the upper 30s
northwest to the middle 40s far south and southeast.

Diurnal stratocumulus clouds may develop in the late morning
into the afternoon on Tuesday around 7000 feet AGL, with
forecast soundings showing some moisture at this level. Modest
west northwest winds are expected, with a southeast lake breeze
possible late in the day. Cooler highs should reach into the
middle 50s.

A shortwave trough should gradually shift southeast toward the
area Wednesday, then shift through the area Wednesday evening.
Forecast soundings are rather dry besides more diurnal
stratocumulus clouds Wednesday afternoon and some middle to high
clouds at times. For now, kept the forecast dry.

Lows Tuesday night should drop into the middle to upper 30s
across most areas away from Lake Michigan, with mainly middle
30s Wednesday night. Winds should be relatively weak each night,
though there may be some middle to high clouds lingering at
times. Still, it looks to be a good chance for frost to occur
each night inland, especially Wednesday night. Frost/freeze
headlines may eventually be needed.

Wood

&&

.LONG TERM...
Issued 1102 PM CDT Mon May 4 2026

Thursday through Monday:

500 mb cluster analysis shows a persistent and anomalous broad
trough/low over and north of the Great Lakes region during this
period. This should keep the area in general cyclonic/northwest
flow at 500 mb.

There may be some showers at times in the Thursday through
Friday period, as a south southwest low level jet and some warm
air advection brings in some moisture and upward vertical
motion. There may also be some differential CVA from a passing
500 mb vorticity maximum on Thursday. A weak front then may
shift southeast through the area on Friday.

Ensemble means and members are generally showing this trend, so
will keep 20 to 30 percent chances for showers at times during
this period. There may be enough instability for a rumble of
thunder Thursday afternoon as well.

One more night of possible frost may occur Thursday night
inland, though lows may remain in the upper 30s or higher.
Temperatures look to slowly moderate Thursday into Friday,
with highs rising into the 60s, with cooler values near the lake
with lake breezes each day.

There is some signal for another frontal passage Saturday
night, which may have more robust moisture profiles to work with
and result in small chances (around 20 percent) for showers.

For the rest of this period, there is more uncertainty in
ensemble trends with timing features through the region. Thus,
will leave mainly 20 to 30 percent chances for showers going at
times in this part of the forecast. Temperatures are generally
trending slowly warmer during this time as well.

Wood

&&

.AVIATION...
Issued 1102 PM CDT Mon May 4 2026

Lingering gusty west northwest winds should gradually weaken
overnight. One area of middle to high clouds will shift east of
the area, with another area moving in overnight and into Tuesday
morning. This should settle more in the southern/southeastern
portions of the area. This may bring some sprinkles or isolated
light showers overnight.

Diurnal stratocumulus clouds may develop in the late morning
into the afternoon on Tuesday around 7000 feet AGL. Modest west
northwest winds are expected, with a southeast lake breeze
possible late in the day.

Wood

&&

.MARINE...
Issued 1102 PM CDT Mon May 4 2026

A cold front will push southeast across the southern portions
of the lake into the overnight hours, shifting gusty southwest
winds to the west northwest. These winds will weaken overnight
as well. The cold front is in association with low pressure
around 29.0 inches moving east across James Bay through Tuesday.

West to northwest winds then persist through the first half of
Tuesday. Winds will become light and variable Tuesday afternoon
and night, as a weak surface ridge passes over the lake. Mainly
light to modest winds are expected Wednesday afternoon and
night, before south to southwest winds return Thursday into
Friday.

Wood

&&

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

$$

Visit us at weather.gov/milwaukee

Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee