602
FXUS63 KMKX 130902
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
402 AM CDT Mon May 13 2024

.KEY MESSAGES...

- Widespread showers with embedded thunderstorms are expected
  Monday afternoon and evening, mainly along and south of a line
  from Madison to Port Washington. A few early-afternoon
  thunderstorms may produce briefly gusty winds.

- Smoke from Canadian wildfires may continue to impact air
  quality through this morning in portions of southwestern
  Wisconsin.

- Additional rounds of showers and storms expected to impact
  southern Wisconsin late this week and into this weekend.

&&

.SHORT TERM...
Issued 402 AM CDT Mon May 13 2024

Today through Tuesday:

A weak cold front is draped across northern Wisconsin, slowly
progressing southward through today. With subsidence behind this
cold front, areas of smoke and poor air quality remain possible
across portions of central Wisconsin through this morning.
Meanwhile, low pressure developing in eastern Kansas this
morning will approach the Middle Mississippi Valley this
afternoon and lead to convergence-based showers and
thunderstorms in far southern Wisconsin. Light southeasterly
winds are expected through much of the day, with a lake breeze
enhanced by the weak northern cold front pushing inland this
afternoon and providing an additional trigger for shower and
thunderstorm development.

Early in the afternoon, with initial thunderstorm development,
surface based CAPE values close to 800 J/kg, boundary layer
lapse rates close to dry adiabatic, and inverted-v sounding
signatures lead to concerns for briefly gusty winds under
heavier storms. However, this threat looks to remain very
isolated, with dewpoints expected to rise back into the upper
50s and bulk shear remaining near or below 25 kt providing less
support than yesterday. Going into the evening hours, expect
winds to rapidly turn northeasterly and bring in stable air from
Lake Michigan. Some elevated instability may remain, allowing
for continued embedded thunderstorms, but the main weather mode
looks to be showers.

Showers slowly sink southeastward overnight, exiting into
Tuesday morning. Meanwhile, low pressure to the south allows for
increased PGF winds from the north-northeast. Expect wind gusts
of 20 to 25 mph Tuesday into Tuesday evening before diminishing
as low pressure shifts into Ohio and weakens.

MH

&&

.LONG TERM...
Issued 402 AM CDT Mon May 13 2024

Tuesday night through Sunday:

Nely winds will continue Tue nt but gradually become lighter as
a sfc ridge builds south from Ontario into wrn WI. The sfc ridge
will then slowly moves across srn WI on Wed. Mostly clear skies
will continue for this period with high temps in the lower 70s
well inland from Lake MI.

A weak sfc trough and upper level trough will then move across MN
Wed nt and into WI on Thu. PWs will increase to 1 inch with
marginal instability ahead of this feature. The fcst soundings do
become fairly saturated in the low to mid levels with little to no
capping so the 50-60 percent PoPs of the NBM looks reasonable.
The showers will continue into the evening over se WI. Another
weaker shortwave trough will then approach and pass through srn WI
for Fri-Fri eve so will have to maintain 20-30 percent PoPs. High
temps will remain in the 70s away from the lake both days.

Upper ridging will then take hold for the weekend with some
differences in timing of the sfc warm frontal passage. A warm
weekend is expected with another Sunday possibly in the 80s. Rain
chances of 20-30 percent chances are forecast via warm, moist
advection.

Gehring

&&

.AVIATION...
Issued 402 AM CDT Mon May 13 2024

VFR conditions expected through this morning, with showers and
thunderstorms developing this afternoon along a weak cold
frontal boundary as well as the lake breeze boundary. Showers
and storms are expected to lower ceilings into MVFR conditions,
although VFR conditions are expected to remain outside showers
and thunderstorms. This evening into tonight, ceilings from
MKE southward through JVL and ENW will continue to fall, with
1000 to 1500 ft ceilings likely and IFR conditions possible,
especially at stations closest to Lake Michigan.

Light southwesterly winds throughout much of the day will shift
to northeasterly from central Wisconsin southwestward late this
afternoon into tonight. Gusts of 20 to 25 kt develop late
tonight into early Tuesday morning.

MH

&&

.MARINE...
Issued 402 AM CDT Mon May 13 2024

A weak cold front draped across the northern third of Lake
Michigan will slowly push southward through today. Expect
southwest winds ahead of this front, with light north winds
behind it. A few thunderstorms are possible across the southern
half this afternoon and evening ahead of this front. Northeast
winds will increase tonight into Tuesday as low pressure
develops in the Middle Mississippi Valley. Winds shift northerly
as low pressure tracks into Ohio Tuesday afternoon and evening,
with winds diminishing into Tuesday night as the low weakens. A
Small Craft Advisory is in effect late tonight through late
Tuesday night for elevated winds and waves in the nearshore
regions. Winds remain light and northerly through Wednesday as
high pressure over the Hudson Bay noses into the region. Winds
are expected to remain light through Thursday.

MH

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...1 AM
     Tuesday to 4 AM Wednesday.

&&

$$

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