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000
FXUS63 KMKX 220941
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
441 AM CDT Mon Apr 22 2024

.KEY MESSAGES...

- Potential for patchy frost early this morning, with more
  frost/freeze concerns Tuesday night and especially Wednesday
  night.

- Elevated fire weather conditions expected today.

- Chances for thunderstorms Tuesday afternoon and early evening,
  with hail and gusty winds possible.

- More active pattern Friday into the weekend.

&&

.SHORT TERM...
Issued 441 AM CDT Mon Apr 22 2024

Today through Tuesday Night:

Patchy frost may develop early this morning in low lying areas,
where temperatures drop into the 30 to 35 degree range. These
colder temperatures are in random parts of the area, so will
not issue a frost/freeze headline.

Gusty southwest winds with deep mixing will combine with very
low relative humidity values to bring elevated fire weather
conditions to the area today. See the Fire Weather section
below for more information.

The gusty southwest winds and some warm air advection will bring
warmer highs into the middle 60s across the area today. These
values may get a little higher if mixing is more robust. One
caveat will be extensive middle to high clouds moving into the
area this afternoon, which may limit the temperature rise a
little.

CAMs and deterministic models are bringing an area of scattered
showers east across the area mainly late this afternoon and
evening. Area of more focused warm air advection and modest
differential CVA should help drive these showers through.
Reduced PoPs to reflect the more scattered nature of the
showers, as forecast soundings are showing somewhat limited
moisture profiles.

There should be a break in the precipitation overnight into
Tuesday morning, with mild air lingering with the gusty
southwest winds. Mild highs in the middle to upper 60s are
anticipated for Tuesday. Models do bring the main cold front
southeast through the area Tuesday afternoon and early evening,
accompanied by a fairly potent 500 mb shortwave trough.

These features should combine to bring more widespread showers
and some thunderstorms through the area. Forecast soundings from
deterministic models and ensembles suggest a few hundred J/kg
of low level CAPE developing before the front moves through,
with strong low layer and deep layer shear. This may help bring
hail and gusty winds with any storms as they move through.

Cold air advection kicks in behind the cold front Tuesday night,
with colder air moving back into the area. May see lows drop
into the upper 20s to lower 30s over a good portion of the area
later Tuesday night, as skies clear out. Winds remain elevated,
so may need a freeze headline for the area in later forecasts.

Wood

&&

.LONG TERM...
Issued 441 AM CDT Mon Apr 22 2024

Wednesday through Sunday:

High pressure to the northeast should push east Wednesday into
Thursday, with dry conditions expected across the area.
Temperatures should be cool near the lake with easterly flow,
and milder well inland. A good chance for frost looks to be
Wednesday night, as winds weaken and clear skies allow for
radiational cooling. Thus, more frost/freeze headlines may be
needed.

It looks like there is general agreement with the ensembles that
low pressure should move northeast through the region Friday
into the upcoming weekend. The details are still uncertain, but
it looks like there could be periods of showers and
thunderstorms at times during this period. Temperatures may
become warm once again during this time, especially if the area
can remain in the warm sector airmass.

Wood

&&

.AVIATION...
Issued 441 AM CDT Mon Apr 22 2024

Gusty southwest winds are expected to develop by middle morning
and linger tonight into Tuesday, before gradually shifting west
Tuesday afternoon. Sustained winds to 20 knots and gusts up to
30 knots are anticipated. Low level wind shear conditions are
likely later this evening into the overnight hours, with
southwest winds of 45 to 50 knots at 1500 to 2000 feet AGL.

Scattered showers should move east through the area later this
afternoon and evening, though VFR conditions are expected. Any
ceilings will remain above 5000 feet AGL this afternoon into
Tuesday.

More widespread showers and some thunderstorms are anticipated
for Tuesday afternoon and early evening. Hail and gusty winds
may occur with any storms. Winds will shift north behind a cold
front Tuesday evening, and remain gusty.

Wood

&&

.MARINE...
Issued 441 AM CDT Mon Apr 22 2024

Low pressure around 29.4 inches will move from southern Manitoba
today and into Lake Superior tonight. South to southwest winds
will gradually increase during this period, with a few gale force
gusts possible tonight over the open waters.

The low will then shift across Lake Huron Tuesday, and into the
New England region Tuesday night into Wednesday. The low will
bring a cold front southeast across Lake Michigan later Tuesday
into Tuesday night. Southwest winds Tuesday will shift north
behind the front into Tuesday night, with some gales possible
over the open waters of Lake Michigan. Building waves are also
anticipated.

A Small Craft Advisory is in effect this afternoon into
Wednesday for the nearshore waters of Lake Michigan. A few gale
force gusts may occur Tuesday night here as well.

High pressure around 30.5 inches will then build into eastern
Ontario on Wednesday, with gusty north winds over Lake Michigan
gradually subsiding. Light east winds Wednesday night will become
southeast on Thursday, as the high shifts east.

Gusty winds and building waves may return Friday and through the
upcoming weekend, as low pressure moves through the region.

Wood

&&

.FIRE WEATHER...
Issued 441 AM CDT Mon Apr 22 2024

Gusty southwest winds of 15 to 25 MPH, with gusts to 30 to 35
MPH, are expected today. Deep mixing heights of 5000 to 7000
feet AGL should occur as well, which will result in relative
humidity values dropping into the 20 to 25 percent range over
most of the area this afternoon. This will result in elevated
fire weather conditions this afternoon across the area. The
relative humidity values could drop a little lower, if deeper
mixing occurs. The middle to high clouds moving in this
afternoon may limit this potential.

Under these conditions, fires will start and spread easily and
could potentially lead to a wildland fire. Please exercise
caution with any activities that involve outdoor fires or create
sparks, including campfires, grilling, and operating large
equipment. Please heed any local burn bans.

Relative humidity values may drop into the 30 to 35 percent
range on Tuesday, perhaps a little lower. Gusty southwest winds
should remain, before widespread showers and some thunderstorms
develop and move southeast through the area Tuesday afternoon
and early evening. More uncertainty lingers here with how low
relative humidity values could get, as clouds will limit mixing
heights. Conditions should improve once precipitation starts to
move through.

Wood

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...1 PM
     Monday to 7 PM Wednesday.

&&

$$

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