469
FXUS63 KMKX 120857
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
357 AM CDT Sun May 12 2024

.KEY MESSAGES...

- Very warm and breezy today. Scattered thunderstorms late this
  afternoon and evening.

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

&&

.SHORT TERM...
Issued 357 AM CDT Sun May 12 2024

Today through Monday:

Light sly winds will develop early this morning becoming breezy
swly winds this afternoon as a wave of low pressure moves across
nrn WI. Low level warm advection will bring the thermal ridge
into srn WI late in the day, and 925 mb temps will warm into
the lower 20s Celsius. This will yield highs in the lower 80s
for most locations. The breezy winds will mix out the dewpoints
to some extent with dewpoint depressions greater than 30F for
the afternoon. Thus Inverted-V soundings are expected for the
afternoon and evening with MLCAPE of 500-1000 J/kg. Just small
chances (20-30 percent) for storms for the afternoon as the cold
front remains well to the north, but the convective temp could
be reached.

The wave of low pressure will weaken tnt as it moves east,
thereby slowing the arrival of the cold front until sunrise
Mon for the nrn CWA. However any storms along the front Sun
afternoon and evening could propagate esely into srn WI
especially toward central WI. Given the inverted-v soundings,
gusty winds will be the main concern.

For Mon-Mon nt, confluent flow is expected btwn an approaching
weak shortwave trough from the nrn Great Plains, and a slow
moving but larger shortwave trough tracking from the central
Great Plains into IL. PWs will increase to 1-1.3 inches while
frontogenesis, PVA and the right entrance region of a jet
supports organized, deep lift. Thus expect showers and possibly
a few storms to develop especially along and south of a line
from Madison to Port Washington with much lesser chances for
pcpn toward central WI.

Gehring

&&

.LONG TERM...
Issued 357 AM CDT Sun May 12 2024

Tuesday through Saturday:

High pressure noses in from the Hudson Bay on Tuesday and remains
dominant through Wednesday, leading to cooler and dry conditions.
Winds off Lake Michigan will lead to the coolest conditions in
southeastern Wisconsin.

A series of shortwaves then approach the area starting Thursday.
Thunderstorms are possible Thursday afternoon as the first
shortwave propagates southeastward. As this shortwave interacts
with a southern Plains low, wrap around precipitation may continue
across southern Wisconsin into Friday. The southern low looks to
exit into Saturday, although an additional shortwave may approach
from the Canadian Prairies Saturday into Sunday. Although there
may be a dry period between Friday and Saturday, enough
uncertainty in timing remains to keep 15 to 30 percent PoPs
through the weekend.

MH

Gehring

&&

.AVIATION...
Issued 357 AM CDT Sun May 12 2024

VFR conditions today through Monday morning but with scattered
high based showers and storms with gusty winds. The prevailing
winds will be gusty swly winds for this afternoon as well.
LLWS will be possible this evening via a wly low level jet of
40-45 kts.

Gehring

&&

.MARINE...
Issued 357 AM CDT Sun May 12 2024

Light south winds early this morning will become breezy south
winds this afternoon as a wave of low pressure around 29.6 inches
and its associated cold front moves across northern Wisconsin. The
low and cold front will then slowly move across northern Lake
Michigan tonight. Thus the winds will shift to light northwest
late tonight over the north half, while modest southwest winds
continue over the south half. The cold front will slowly move
south on Monday bringing light to modest northerly winds to the
entire lake.

Breezy northeast winds and building waves will then develop over
the south half late Monday night into Tuesday night as low
pressure passes to the south, while high pressure extends from
western Hudson Bay into Wisconsin.

A Small Craft Advisory is in effect this afternoon and evening
from Sheboygan to Winthrop Harbor for gusty sswly winds. Another
Small Craft Advisory will likely be needed from early Tue AM
into Tue nt due to persistent and brisk nely winds and building
waves.


Gehring

&&

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

&&

$$

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