928
FXUS63 KMKX 040246
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
946 PM CDT Fri May 3 2024

.KEY MESSAGES...

- A few stronger thunderstorms are possible in southeast WI
  Saturday afternoon.

- Additional showers and thunderstorms are expected during the
  middle portions of next week.


&&

.UPDATE...
Issued 927 PM CDT Fri May 3 2024

Some stratus may move in from Lake Michigan Saturday morning,
impacting far eastern Wisconsin. Then some sun is expected there
midday before clouds return with the frontal passage. No changes
to the shower and thunderstorm chances for Saturday. See
previous discussion.

Marquardt

&&

.SHORT TERM...
Issued 351 PM CDT Fri May 3 2024

Tonight through Saturday night:

Clear skies will prevail over southern WI tonight. Look for
winds to become light and variable overnight as high pressure
moves across the region, then start increasing out of the
southeast in the morning as the high departs. Dewpoints mixed
down to around 40 this afternoon, so that should help our
evening temps drop into the lower 50s quickly. Lows should be in
the upper 40s, but can`t rule out mid 40s toward central WI.

A line of showers and thunderstorms along a weak cold front will
be tracking into the western part of WI Saturday morning. This
front is associated with a mid level shortwave trough and the
resultant weak surface low. The stronger forcing with that
shortwave will stick closer to the entrance region of the upper
jet, which will track across northwest WI. Therefore, the line
of showers with a chance for lightning will be weakening as it
tracks into south central WI late Saturday morning.

Once the front reaches south central WI from around Janesville
to Fond du Lac, there will have been enough daytime heating to
allow for some build-up of CAPE (up to 1000 j/kg) in southeast
WI to support an increase in shower and thunderstorm
development. The shear is on the higher end and will be enhanced
by the lake breeze. While the mid level forcing will be weaker,
the surface forcing will be stronger. Thus, there is a chance
for a stronger storm or two in far southeast WI during the
afternoon. Small hail and gusty winds are the threats. The
tornado threat is non-zero if storms interact just right with
the lake breeze boundary. The window of opportunity looks like
3 to 8 PM for areas between Janesville, Port Washington, and the
WI/IL border.

Cronce

&&

.LONG TERM...
Issued 351 PM CDT Fri May 3 2024

Sunday through Friday:

High pressure will take hold of southern WI Sunday and Monday.
Look for increasing southeast winds Mon afternoon as low
pressure approaches from the Plains. That closed low will stay
fairly stationary in the Northern Plains Mon-Tue as it occludes,
but showers and thunderstorms along the warm front should
extend into southern WI on Tuesday. As the upper low either
moves eastward or weakens, another round of showers and storms
is possible over southern WI on Thursday. The weather pattern
associated with the storm chances is complicated and
unorganized, which is the typical nature of upper lows. Expect
changes to the forecast many times between now and then.

Unfortunately, that upper low does not move out of the Upper
Midwest until at least Saturday, which means a prolonged period
of clouds and precip chances for southern WI until then.

Cronce

&&

.AVIATION...
Issued 927 PM CDT Fri May 3 2024

Some clouds may move in from Lake Michigan Saturday morning
impacting far eastern Wisconsin, including MKE. Cloud bases
could be scattered to broken around 1000ft for a few hours from
10 to 14Z before rising and scattering. There is a lot of
uncertainty whether this will occur and VFR could prevail.

East winds will become south and gust around 20 knots during
the day Saturday for areas inland of Lake Michigan. A line of
scattered showers and thunderstorms will be weakening as it
moves into south-central Wisconsin late Saturday morning. Once
it reaches Janesville to Fond du Lac more widespread showers an
thunderstorms are expected to develop late Saturday afternoon
and early evening.

Marquardt

&&

.MARINE...
Issued 351 PM CDT Fri May 3 2024

Light southeast winds are expected tonight into Saturday as high
pressure slides across the Upper Great Lakes. Showers and
thunderstorms are possible along a cold front late Saturday
afternoon through the evening. High pressure will return for
Sunday and Monday. The next low pressure system that may bring
gusty winds below gale level and another round of thunderstorms will
track across northern Lake Michigan Tuesday into Wednesday.

Cronce

&&

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

$$

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