-- Discussion containing changed information from previous version are highlighted. --
674
FXUS63 KMKX 160244
AFDMKX

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

.KEY MESSAGES...

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- Showers likely and scattered storms for Sun AM.

- 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.
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&&

.UPDATE...
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Issued 944 PM CDT Sat Jun 15 2024

Precipitation chances will finally increase toward sunrise west
of MSN then ewd across srn WI through the morning as the
shortwave trough currently over the Mid MO River Valley lifts
newd across central and srn WI. A strong surge of moisture
transport at 850 mb will bring 1000-1500 J/KG of elevated CAPE
with it. Some of the CAMs have become more aggressive with
showers and storm coverage so increased rain chances to 50-70
percent with the se corner of WI with the lowest chances. Pcpn
and clouds will then decrease early in the afternoon as the
shortwave trough exits. Very warm and humid conditions will then
develop.


Gehring
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&&

.SHORT TERM...
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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 nearshore 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
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&&

.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...
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Issued 944 PM CDT Sat Jun 15 2024

LLWS will develop late tnt via a sly low level jet of 40-50 kt and
continue until 13-15Z Sun. An area of showers and scattered
storms is expected to move from west to east across srn WI from
sunrise through the morning. Areas of MVFR Cigs may develop
within and briefly after the rainfall for locations north and
west of Madison. Skies will then become partly cloudy for the
afternoon with VFR conditions and swly wind gusts of 25 kt. VFR
conditions will continue into Sun nt.

Gehring
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&&

.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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