NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 261917
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
217 PM CDT Sun Apr 26 2026
.KEY MESSAGES...
- Widespread showers (80 to 100 percent chances) and scattered
thunderstorms return for Monday into Monday night. There is
the potential for severe weather Monday afternoon and evening,
with locally heavy rainfall also possible.
- Cooler temps Tuesday through the end of next week, with a
frost/freeze potential by the end of the week.
&&
.SHORT TERM...
Issued 217 PM CDT Sun Apr 26 2026
Tonight through Monday night:
Aside from lingering clouds near the lake, skies should start
out mostly clear this evening, with increasing mid and high
level clouds overnight as warm advection aloft increases ahead
of an approaching low. Showers and a few storms associated
with the strong warm advection will reach the southwest
forecast area by or shortly after daybreak. This area will lift
through southwest to northeast through the morning hours,
exiting the east by early afternoon. Only marginal instability
with this round of precip, so severe storms are not expected
through the morning.
There should be a lull in precip during the early to mid-
afternoon hours tomorrow. This may allow for a period of time
for temps to warm up a bit under southeast winds, as surface
low pressure lifts from central Iowa into west-central
Wisconsin. Not expecting to see the sun much at all, but
filtered sunshine through lingering mid/high level clouds may be
enough for temps to rise into the mid/upper 60s, providing some
destabilization for the next round of storms.
By late afternoon, the more solidly defined warm sector based
on temps from the sfc to 925 mb is expected to start to lift
into the forecast area from the southwest, sliding through the
southern half of the forecast area during the late afternoon and
evening hours. Confidence has increased in a window of modest
surface based instability during this time frame ahead of the
approaching cold front. Given a strong LLJ overhead and plenty
of shear, it's looking more probable that an organized line of
storms will push through areas mainly south of I-94 during the
late afternoon and evening. Though some hail is not out of the
question, this setup is trending towards a damaging wind and
QLCS tornado threat if severe storms develop. The peak window
of opportunity for severe storms tomorrow should be from 5 to 10
pm, with the storms departing to the east late in the evening.
Will continue to keep an eye on a heavy rainfall threat as well
tomorrow, given models push the ~1.50" precipitable water
values into southern portions of the forecast area. Localized
flooding would be a concern given saturated soils and rivers
remaining elevated.
DDV
&&
.LONG TERM...
Issued 217 PM CDT Sun Apr 26 2026
Tuesday through Sunday:
Northwest flow will develop Tuesday behind the departing low
and will likely persist through the remainder of the week and
into the weekend. Surface high pressure will bring quiet
weather much of this time, though a shortwave or two may bring
some light rain chances at times. Temps in this pattern will run
near to a few degrees below normal through at least late week.
Could see a return of a frost/freeze potential the second half
of the week.
DDV
&&
.AVIATION...
Issued 217 PM CDT Sun Apr 26 2026
The area of low clouds in the east and over the lake is
gradually decreasing in areal coverage this afternoon, with a
return to VFR conditions likely by evening. There is a signal
that some lower clouds may linger near the lake north of
Milwaukee through late evening. Otherwise increasing mid and
high level clouds are expected overnight. East to southeast
winds will also gradually pick up overnight.
Showers and a few storms associated with strong warm advection
will reach the southwest forecast area by or shortly after
daybreak Monday. This area will lift through southwest to
northeast through the morning hours, exiting the east by early
afternoon. Severe storms are not expected through the morning.
LLWS is likely to develop in at least the eastern forecast area
by mid-morning as a strong LLJ moves overhead. Lower clouds
in the 800-1200 ft range area likely to spread in during the
morning hours as well, lingering into the afternoon.
There should be a lull in precip during the early to mid-
afternoon hours tomorrow. There is increasing confidence that
an organized line of storms will then push through areas mainly
south of I-94 during the late afternoon and evening. Though
some hail is not out of the question, this setup is trending
towards a damaging wind and QLCS tornado threat if severe storms
develop. The peak window of opportunity for severe storms
tomorrow should be from 22Z to 03Z pm, with the storms
departing to the east late in the evening.
DDV
&&
.MARINE...
Issued 217 PM CDT Sun Apr 26 2026
East to northeast winds of 5 to 10 knots will continue into the
evening hours today. Low pressure of 29.4 inches is expected to
lift from northeast Kansas early Monday to Lake Superior by
later Monday night. Winds will become east to southeast tonight
ahead of the low, increasing to around 10-15 knots. Winds will
then increase Monday into Monday night out of the south to
southeast as the low approaches. The cooler lake temps should
dampen the threat for gales across the lake, with Small Craft
Advisory conditions likely for the nearshore waters. Breezy
westerly winds are expected Tuesday behind the departing low.
DDV
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...4 AM
Monday to 1 PM Tuesday.
&&
$$
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