072
FXUS63 KMKX 122052
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
352 PM CDT Sun May 12 2024

.KEY MESSAGES...

- Scattered thunderstorms late this afternoon and evening. Gusty
  winds up to 50 mph are possible.

- Widespread rain with embedded thunderstorms Monday afternoon
  lingering and evening, mainly along and south of a line from
  Madison to Port Washington.

&&

.SHORT TERM...
Issued 352 PM CDT Sun May 12 2024

Tonight through Monday night:

Scattered thunderstorms developed in a line across northern Iowa
and are slowly expanding into southwest WI this afternoon. These
are roughly along 700mb frontogenesis and are being triggered
with help from a weak mid level shortwave and also by reaching
the convective temperature. Low levels are very dry with steep
low level lapse rates up to 8000 ft, so gusty winds up to 50
mph are the main threat with these storms, although pea size
hail is possible.

The next line of scattered storms of interest is currently up
in southeast MN and this is associated with the low level cold
front (surface to 850mb). This front will make its way into
south central WI this evening, but then stall. Convection along
it is expected to be weakening as it reaches our forecast area
near the Dells mid to late evening.

With that boundary stalled over southern WI, additional showers
and elevated, weak thunderstorms are expected to develop by
midday Monday. Areas toward central WI have lower confidence in
these showers, but southern WI has a high probability of showers
and storms (80 to 100 percent) during the late afternoon and
evening hours.

Depending on sky cover Monday morning, a high around 80 could
sneak into far southeast WI before the showers develop. This
area would be more susceptible to a stronger storm or two, but
that would be short lived.

Winds will switch to northeast near the lakeshore by late
morning in Sheboygan and spread down toward Kenosha through the
mid afternoon as a cold front races down the lake faster than
inland areas. Lower clouds and much cooler temperatures, along
with increasing northeast winds, will help lower clouds develop
as the day goes on Monday late afternoon and night. The
scattered showers will end from north to south overnight Monday
night into Tuesday morning. Models are trending a little slower
with clearing the precip out.

Cronce

&&

.LONG TERM...
Issued 352 PM CDT Sun May 12 2024

Tuesday through Sunday:

Southern Wisconsin will get shortwave ridging aloft Tuesday into
Wednesday for dry and warm conditions. There looks to be a mid
level trough approaching from the west on Wednesday night. Still
uncertain on whether thunderstorms develop, but there will also be
an approaching cold front. Some weak lift is indicated late
Wednesday night into Thursday for shower activity. Highest QPF
looks to be east and southeast of the forecast area on Thursday.
Surface wind direction could also be tricky on this day.

This system kicks well east by Friday for a dry and breezy day
for southern Wisconsin. In fact, mostly dry and zonal flow aloft
should hold through next weekend. This will very likely result in
warm temperatures and no precipitation, although diurnal
convection can be expected each day.

KPL

&&

.AVIATION...
Issued 352 PM CDT Sun May 12 2024

Scattered thunderstorms are expected across southern WI late
this afternoon and evening. Storms are expected to remain below
severe levels, but gusty winds and small hail are possible.
After a lull in the precip chances overnight into Monday
morning, more widespread showers with embedded thunderstorms are
expected for the afternoon and evening. They should end north to
south overnight into Tuesday morning.

MVFR ceilings are looking likely for Monday afternoon and
evening with the showers. As the day goes on, there is an
increasing chance for MVFR (50 to 70%) ceilings to work inland
from lakeshore areas and IFR (20 to 30%) ceilings from Milwaukee
to Janesville south in the evening.

Winds will be gusty out of the southwest today and lighter
Monday. However, a cold front will race down the lake midday and
cause a sudden wind shift near the lakeshore. Cronce

&&

.MARINE...
Issued 352 PM CDT Sun May 12 2024

Gusty southerly winds up to 25 kt are expected this afternoon
in the nearshore area. This is a marginal Small Craft Advisory
since mixing deep enough to get those gusts is questionable as
there is a constant battle with that stable lake air. End time
of the gusty wind threat is late evening. Thunderstorms are
possible this evening and again Monday afternoon and evening
with a cold front in the vicinity.

Winds will suddenly shift northeast along the lakeshore midday
Monday as a cold front races down Lake Michigan. Gusty northeast
winds are expected Monday night through Tuesday, so another
Small Craft Advisory will be needed.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 10 PM
     Sunday.

&&

$$

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