404
FXUS63 KMKX 152004
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
304 PM CDT Sat Jun 15 2024

.KEY MESSAGES...

- Chance for thunderstorms late Saturday into Sunday.

- Hot weather is anticipated Sunday into the middle of the work
  week. Heat indices in the middle 90s are likely Sunday and
  Tuesday and heat index values in the upper 90s are likely on
  Monday.

- Additional chances for storms the rest of this week. Severe
  storms, particularly Wednesday, cannot be ruled out.

&&

.SHORT TERM...
Issued 300 PM CDT Sat Jun 15 2024

Tonight and Sunday:

As the system pushes in through the evening and overnight hours
we will gradually moisten up in the low levels further west. It
will likely (80%) remain drier further east. The upper level
shortwave will continue through the region into the evening and
overnight but the difference will be the LLJ jet building into
the region which will enhance forcing in the mid levels. The
issue with this is the LLJ will largely be setting up further
west. Given the drier air further east it could set up a fairly
stark boundary for dry and wet. There is some storm potential
with this given the LLJ and enhanced shear (30-40kts) that it
will provide but given the timing the instability will be rather
limited and region may largely be capped so any storms are
largely expected to be weak and elevated.

As the LLJ shifts a tad east we could see storms and showers
slide east a bit possible affecting parts of southeast WI but
models are conflicted on this potential. Overall, the best
chances (80-90%) for precip/storms from this system will be
further northwest though the entire northwest half of the CWA
will see chances (60-90%) with the southeast more likely
(40-60%) to remain dry. This system will slide out by Sunday
morning with the rest of Sunday looking dry as we remain capped.

In addition, due to increasingly breezy southeast winds tonight
into Sunday morning to 25-30 mph, waves will increase to 3 to 5
feet along the nearshores of Ozaukee and Sheboygan counties.
Waves will be highest Sunday morning and afternoon. This will
bring a High Swim Risk to the area from later tonight through
late Sunday evening. Kenosha, Racine and Milwaukee counties will
still see Moderate Swim Risk conditions but the focus of the
highest waves will be further north.

Kuroski

&&

.LONG TERM...
Issued 300 PM CDT Sat Jun 15 2024

Sunday night through Saturday:

Late Sunday night into Monday morning we should expect the LLJ
to ramp up again to the west, though weaker. This, in
combination with the warm front setting up well north of the CWA
will likely fire storms across parts northern and central WI.
These may drift south but as they do they will likely weaken as
they move into a more capped environment to the south. Some
showers or weak storms may sneak into the north side of the CWA
but much of the area will remain dry overnight into Monday
morning. As we move into the day Monday we will see chances for
pop up storms given the lapse rates and large instability of
2000-3000 J/kg (possibly more). Now there is much forcing to
work with but we may see enough effect from the fringes of LLJ
to the west or even the lake breeze to allow for some
convection. Severe storms are not expected but it remains
possible for a hailer with some wind given the large instability
and lapse rates.

Tuesday looks more quiet but there will still be slight chance
for additional pop up storms though with limited forcing outside
of maybe the lake breeze (which may be enough) and any outflows
thereafter. But there will still be enough instability to
potentially bring tall storms capable of a few larger hailstones
and/or a strong gust.

Wednesday will feature decent chances (60%) for showers/storms
with even a chance for some severe storms as well. While there
is still plenty of uncertainty, especially with regards to
timing, the instability and increased shear (30-40 kts 0-6km)
as a surface front comes through with some shortwave support in
the upper levels. This will be the day to watch for potential
for severe storms.

Uncertainty beyond Wednesday really balloons but there will
likely chances for showers/storms at least through the weekend
with severe storms remaining possible.

While not mentioned earlier, Sunday through Tuesday will feature
very warm temperatures in the upper 80s to mid 90s with Monday
being warmest day. With 925mb temps in the upper 20s we could
see temperatures in the southeast WI, especially with
downsloping from breezy southwest winds, reach the upper 90s in
spots.

Kuroski

&&

.AVIATION...
Issued 300 PM CDT Sat Jun 15 2024

VFR conditions are largely expected through the TAF period.
However, while much of the evening and night is expected to
remain quiet as we head into the late overnight and early Sunday
morning period we will see chance for showers and maybe even a
few weak storms slide into parts of southern WI. Most of this
is expected to remain off toward west central WI. There remains
a decent chance (60%) for a shower or storm closer to Madison
but the better chance will remain north and west. While we
cannot rule out a few isolated showers or storms further east,
most models have things dissipating as the push east. There
remains a slight chance (20%) for a period of MVFR VSBYS with
precip. Otherwise MVFR CIGS will likely (70%) remain off to the
north and west of southern WI (best chance (30%) is to see an
hour or 2 of MVFR CIGS in Madison or Sheboygan). Scattered to
broken CIGS expected across most of southeast WI during this
period. System will push out by late Sunday morning or early
Sunday afternoon. Otherwise expect southerly winds gradually
increasing overnight into Sunday, turning more SSW and
persisting through much of the day.


Kuroski

&&

.MARINE...
Issued 300 PM CDT Sat Jun 15 2024

High pressure over Ontario will move into New England by
tonight as low pressure deepens over the northern plains. East
winds will become southeast at 20 knots or less. On Sunday the
low will approach Lake Superior and south winds will increase.
Gusts of 30 knots are possible. Another area of low pressure
will approach from the central plains on Monday and Tuesday and
south winds will continue. Winds may be brisk at times. A front
will move through the lake sometime mid or late week.

Kuroski

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060...1 AM Sunday to 1 AM
     Monday.

LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...1 AM
     Sunday to 1 AM Monday.

&&

$$

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