645
FXUS63 KMKX 020255 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
955 PM CDT Mon Jul 1 2024

.KEY MESSAGES...

- River flooding and high water levels continue this week.
  Additional rises will be possible with any heavier rainfall
  that occurs later tonight through Tuesday night.

- Rain and thunderstorms are expected at times later tonight
  into Tuesday morning, and again later Tuesday into early
  Wednesday morning. Primary concern is heavy rainfall,
  especially for Tuesday night.

- Shower and thunderstorm chances return for Independence Day
  and Friday.

&&

.UPDATE...
Issued 955 PM CDT Mon Jul 1 2024

An area of showers and a few storms are trying to move eastward
into the western parts of the area, aided by differential CVA
and some warm air advection. This will be fighting very dry low
levels per area forecast soundings, and ceilings are generally
above 8000 feet AGL. Think that some very light showers or
sprinkles may make it into the far western parts of the area
over the next few hours, and may need further adjustments to
PoPs in that area.

The main area of rain and thunderstorms with heavy rainfall is
likely to focus from northern Iowa across southwest to north
central Wisconsin overnight into Tuesday morning, aligned with
the southwesterly low level jet nose and focused warm air
advection. The northwestern parts of the area should get in on
this activity, though again the heaviest rainfall should remain
to the northwest.

There should be a lull in the activity later Tuesday morning
into the afternoon, before more rain and storms moves into
mainly southern Wisconsin by later Tuesday afternoon, continuing
into Tuesday night/early Wednesday morning. This second round
would be more impactful for heavy rainfall, as the low level jet
nose focuses over the region with high precipitable water
values over 2.00 inches. The right entrance region of the upper
jet also helps with upward vertical motion, and the slow moving
cold front moves slowly east and parallel to the upper flow.
Thus, may see more training of convection and heavy rainfall
over the area.

Areas southwest of Madison will have the best chances for
greater then 2.00 inches of rainfall per ensembles. May need to
consider a Flood Watch for flash flooding in later forecasts,
depending on how much we get in northwest parts of the area with
the first round of rainfall.

High swim risk/Beach Hazards Statement continues for Tuesday for
all Lake Michigan beaches, for high waves causing dangerous rip
currents. This will linger into Tuesday night for beaches in
Sheboygan and Ozaukee County, with south winds continuing to
bring high waves to those areas. Stay out of the water during
this period.

Wood

&&

.SHORT TERM...
Issued 310 PM CDT Mon Jul 1 2024

Tonight through Tuesday night:

Dry and pleasant weather continues until late tonight (after
midnight). A surface pressure trough extending south from low
pressure in Manitoba (connecting to a satellite low in KS) works
with the departing high pressure system to generate strong 850-700mb
WAA late tonight, leading to a gradual increase in rain shower
coverage early Tuesday morning, with a chance for a few weak
elevated thunderstorms amongst the showers (though HREF Mean MUCAPE
is < 500 joules). One or two lulls in shower / weak
thunderstorm activity may occur mid Tuesday. In the late
afternoon / evening, the LLJ strengthens overhead (40-45 kts,
PWAT climbs to around 2.0 inches), potentially fueling showers
and weak thunderstorms capable of higher rainfall rates. Shower
and thunderstorm activity gradually decrease late Tuesday night
as a cold front crosses the region, moving clear of the CWA by
around 7 AM CDT Wednesday.

Sheppard

&&

.LONG TERM...
Issued 310 PM CDT Mon Jul 1 2024

Wednesday through Monday:

The passage of a weak high pressure system will lead to a lull
in active weather on Wednesday. West winds 10 to 20 mph behind
the cold front will only briefly provide CAA. The subsidence of
the approaching high will clear the skies out gradually, sending
Wednesday`s daytime high temps into the mid 80s. West winds
abate the lake breeze and allow areas east of the Kettle Moraine
to soar into the upper 80s.

The active weather pattern returns Thursday into Friday as low
pressure develops in the northern Plains and tracks eastward. A
semi persistent trough axis over the northern plains may allow
additional low pressure systems to follow a similar track,
leading to occasional shower / storm chances through the end of
the forecast period.

Sheppard

&&

.AVIATION...
Issued 955 PM CDT Mon Jul 1 2024

May see a few showers approach Madison and Janesville over the
next few hours, though they should be very light or just
sprinkles. Southeast winds will linger overnight into Tuesday
morning, with some gusts to 15 to 20 knots at times. Low level
wind shear conditions are possible overnight, though will leave
out of TAFs for now, with 2000 foot AGL south winds around 40
knots.

More rain and thunderstorms should move into areas northwest of
a Monroe to Sheboygan line overnight into Tuesday morning, with
more scattered showers and a few storms elsewhere. May see MVFR
to IFR visibility values in any heavier rain or storms, with
VFR conditions expected otherwise. South to southeast winds are
expected Tuesday.

A lull in the showers and storms is anticipated from later
Tuesday morning into the afternoon, before more rain and storms
moves into southern Wisconsin later Tuesday afternoon into
Tuesday night and linger into early Wednesday morning. This
period may see heavy rainfall and more widespread MVFR to IFR
visibility values, as well as some MVFR ceilings developing by
Wednesday morning.

South to southwest winds should weaken Tuesday night into early
Wednesday morning. May see some low level wind shear conditions
during this time, with southwest winds around 35 knots at 2000
feet AGL.

Wood

&&

.MARINE...
Issued 310 PM CDT Mon Jul 1 2024

With high pressure around 30.3 inches lingering over Lake Michigan,
winds will be light and variable for the rest of today,
predominantly westerly over the northern edge and easterly over
the southern edge. High pressure will continue moving east,
exiting the western Great Lakes Region tonight. Winds will become
southeasterly and increase tonight as low pressure around 29.4
inches moves northeast from Saskatchewan toward James Bay. Winds
will remain south to southeasterly until Tuesday night when a cold
front crosses the lake. Rain and thunderstorms are expected with
the frontal passage. Southwest to west winds are expected behind
the front. Weak high pressure returns to the region Wednesday
night into Thursday bringing a return of light and variable
winds.

Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060...6 AM Tuesday to 1 AM
     Wednesday.

     Beach Hazards Statement...WIZ066-WIZ071-WIZ072...6 AM Tuesday
     to 7 PM Tuesday.

LM...Small Craft Advisory...LMZ643...6 AM Tuesday to 1 AM Wednesday.

     Small Craft Advisory...LMZ644-LMZ645-LMZ646...6 AM Tuesday to
     7 PM Tuesday.

&&

$$

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