921
FXUS63 KMKX 261515 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1015 AM CDT Wed Jun 26 2024

.KEY MESSAGES...

-  Showers and scattered storms for Friday and Friday night.
   There is a Marginal Risk for severe thunderstorms.

-  River flooding and high water levels will continue this week
   and into this weekend.

-  Moderate Swim Risk for Lake Michigan beaches later today and
   tonight.

&&

.UPDATE...
Issued 1015 AM CDT Wed Jun 26 2024

Light showers continue to shift east out of the far southeast
portions of the area, as the main 500 mb shortwave trough pushes
through. There is clearing behind the shortwave, and would
expect skies to continue to become at least partly sunny into
this afternoon. Diurnal cumulus clouds should develop this
afternoon, and there may be some sprinkles that occur with some
lingering weak instability during peak heating. Added this into
the forecast for this afternoon. Winds should shift northeast
near the lake this afternoon, bringing cooler temperatures
there. Highs into the lower 80s should generally occur inland.

A Moderate Swim Risk is anticipated for later today into tonight
for the Lake Michigan beaches, with increasing northeast winds
and building waves of 2 to 4 feet.

Wood

&&

.SHORT TERM...
Issued 431 AM CDT Wed Jun 26 2024

Today through Thursday:

High based light showers or sprinkles will continue across the
area this morning via mid level frontogenesis ahead of a
shortwave trough approaching from nrn MN. At the surface a n-s
sfc trough will shift swd across the area this afternoon with
increasing cold advection. A shift of nwly winds to nely winds
is expected at the lake first then farther inland through the
evening.

Nwly flow aloft will then prevail through Thu with sfc high
pressure arriving late tonight then gradually ewd on Thu. Temps
will cool into the 50s tnt with pleasant highs in the lower to
middle 70s for Thu.

Gehring

&&

.LONG TERM...
Issued 431 AM CDT Wed Jun 26 2024

Thursday night through Tuesday:

High pressure will move to the lower Great Lakes Thu nt while a
sfc trough moves across the Great Plains. Sely winds will
increase along with cloud cover but pcpn is expected to hold off
until Fri.

A well organized upper trough will then track from the high
plains of MT to the Lake Superior region from Fri into Sat. A
sfc low will track ahead of it with its warm front approaching
and moving into srn WI Fri afternoon and night. A good surge of
low to mid level warm, moist advection and PWs approaching 2
inches will bring widespread showers and a few storms for Fri-
Fri nt. However, due to poor lapse rates any meaningful
elevated or sfc based CAPE comes after much of the pcpn occurs.
The cold frontal passage will then occur Sat AM but convective
development will be spotty and probably more widespread over IL.
Rainfall amounts are currently expected to remain below 1 inch.
Nwly winds and cold advection to then take hold late Sat into
early Sun with high pressure approaching late in the day. A
relatively cool and pleasant day is expected for Sun.

Another round of cyclogenesis will then occur across the nrn
Great Plains into Ontario for Mon nt-Tue with more warm frontal
pcpn expected over srn WI.

Gehring

&&

.AVIATION...
Issued 1015 AM CDT Wed Jun 26 2024

Light showers continue to shift east out of the far southeast
portions of the area. Skies should continue to become at least
partly sunny into this afternoon. Diurnal cumulus clouds should
develop this afternoon, and there may be some sprinkles that
occur. Winds should shift northeast near the lake this
afternoon, with northwest winds elsewhere.

High pressure moving across the area tonight into Thursday will
continue to bring quiet weather. Light and variable winds
tonight may allow for ground fog in low lying areas. East to
northeast winds are generally expected on Thursday, with middle
to high clouds moving east into the area in the afternoon.

Wood

&&

.MARINE...
Issued 431 AM CDT Wed Jun 26 2024

Winds will increase a bit over Lake Michigan today with the
passage of a cold front. Light westerly winds over southern Lake
Michigan early this morning will become modest northwest winds
later this morning, then northerly for the afternoon. Over the
north half, light northwest winds early this morning will become
modest northerly winds later this morning. The modest northerly
winds will continue tonight into Thursday morning.

High pressure around 30.0 inches will then slowly move across Lake
Michigan on Thursday. Increasing south winds are then forecast
for Friday, becoming southwest to west on Saturday, as a cold
front moves through the region. Chances for showers and
thunderstorms increase during this period.

Increasing southerly winds on Friday may build waves to 3 to 5
feet north of Port Washington and require a Small Craft
Advisory.

Gehring

&&

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

$$

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