891
FXUS63 KMKX 040314 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1014 PM CDT Mon Jun 3 2024

.KEY MESSAGES...

- Rounds of thunderstorms will continue late this evening into
  at least early tonight. Flash flooding remains a concern due
  to the repeated rounds of storms on top of already saturated
  soils.

- Warm/muggy conditions continue Tuesday.

- Thunderstorms are expected to develop Tuesday afternoon. An
  isolated severe storm with wind and hail possible during the
  afternoon to evening hours. Additional thunderstorms develop
  Tuesday night into Wednesday along a cold front.

- Northwest winds bring cooler and drier air to southern
  Wisconsin for the second half of this week.

&&

.UPDATE...
Issued 1014 PM CDT Mon Jun 3 2024

Persistent moisture transport into southern Wisconsin is helping
to keeps storms developing late this evening. A local maximum of
precipitable water values of 1.6 to 1.7 inches continues to sit
over the forecast area. The main concern with storms into
tonight is a persistent lightning threat along with locally
heavy rainfall due to the high PWs. Kept the Flash Flood Watch
going as is based on latest radar and model trends.

The storms are currently focused largely north of I-94, but
there are some indications that the activity may pick up along
and south of the interstate over the next couple hours. Will
continue to monitor these trends given the concern for more
storms over areas that have already received 2-4 inches today.
Showers and storms should wind down between midnight and 3 am
per latest short term models, with mainly quiet weather likely
through Tuesday morning.

DDV

&&

.SHORT TERM...
Issued 337 PM CDT Mon Jun 3 2024

Tonight through Tuesday night:

Showers and storms have developed along the MCV boundary along the
Mississippi River. These storms are expected to progress east
northeastward tonight and combine with a lingering boundary
draped from Port Washington to Madison, leading to severe
weather potential across southern and southwestern Wisconsin.
The primary threat with these storms looks to be wind, with
surface based CAPE values near 2000 J/kg in southwestern
Wisconsin and close to 1000 J/kg in southeastern Wisconsin
combining with PWATs near 1.5 inches and equilibrium levels near
40 kft to produce favorable conditions for wet microbursts.
Threat for large hail (greater than one inch in diameter) still
exists within stronger cells, especially going into this
evening. However, mid-level lapse rates only near 6.5 degrees
C/km is expected to inhibit explosive growth and mitigate hail
sizes.

Mesoscale modeling is indicating SRH in the lowest km will
increase to near 100 m2/s2 into this evening as storms develop
cold pools, leading to a chance for an isolated tornado along
line segments.

As storms become cold pool dominant late tonight, heavy rain
becomes the primary threat. PWAT values are forecast to be near
1.5 inches, with warm, moist southeasterly to southerly flow
throughout the overnight hours. Storms that manage to develop
parallel to shear may produce training thunderstorms that
produce heavy rain. MUCAPE remains around 700 J/kg throughout
the overnight hours, so generally not expecting all PWATs to be
realized as rainfall. However, the environment is primed for
heavy rainfall and flooding potential will be monitored tonight.

Rain diminishes and moves out into Tuesday morning, with
clearing skies and continued southerly flow bringing in
additional instability and assisting with atmospheric recovery.
Surface based CAPE values near 2500 J/kg are possible, with a
few CAMS indicating solutions up to 3000 J/kg. A shortwave
moving northeastward through southern Wisconsin will then have
the potential to kick off additional thunderstorms in this
primed airmass. Bulk shear values remain near 25 kt, which may
provide a mitigating factor in severe weather. However, damaging
wind gusts and hail are possible within stronger thunderstorms.

MH

&&

.LONG TERM...
Issued 337 AM CDT Mon Jun 3 2024

Wednesday through Monday:

The main cold front that is associated with an extension of vorticity
that stems from a closed upper low stationed over central Alberta
Canada will push through WI early Wednesday. The showers and
thunderstorms along that front are expected to clear southeast WI
by mid morning, but likely by 7 AM. Another shortwave trough that
is rounding the base of the closed upper low will slide into
southern WI during the late afternoon or evening. This will help
to steepen the low and mid level lapse rates over southern WI and
allow for scattered showers. Models are not showing super steep
rates right now because the wave might come through past the peak
daytime heating, so thunder seems less likely, but kept the
mention in the forecast for now.

We will remain under that cyclonic flow until Friday night when
the upper low finally shifts into the eastern Great Lakes region.
Highs will be in the lower 70s Thu-Fri, with lows in the lower
50s. There may be scattered afternoon showers each day, but
moisture might be too sparse. There will at least be widespread
diurnal cumulus clouds each day.

Yet another weak shortwave should move through Saturday afternoon
and night, thus another chance for showers and storms. More
sunshine, slight ridging, and a little return moisture will allow
for temps to get back into the mid-upper 70s for the weekend.

Cronce

&&

.AVIATION...
Issued 1014 PM CDT Mon Jun 3 2024

Rounds of storms will continue late this evening into at least
early tonight. The main concern with these storms will be a
persistent lightning threat along with locally heavy rainfall
that could result in some flash flooding. The storms are
currently focused largely north of I-94, but there are some
indications that the activity may pick up along and south of the
interstate over the next couple hours. Mainly VFR conditions
will persist into Tuesday, outside of lower ceilings and
visibilities within stronger storms.

Showers and storms should wind down between 05Z and 08Z per
latest short term models, with mainly quiet weather likely
through Tuesday morning. More storms will be possible tomorrow
afternoon into then evening with daytime heating as a shortwave
approaches, with more storms arriving from the west by late
evening along the cold front.

DDV

&&

.MARINE...
Issued 337 PM CDT Mon Jun 3 2024

Low pressure centered over northern Minnesota will continue to
weaken and light southerly winds will persist. Dense fog is
possible over the north half tonight, but there is not enough
confidence to issue a headline at this time. Patchy dense fog is
possible in nearshore regions as well after rain and storms
exit.

A low pressure trough will cross the Northern Plains tonight
through Tuesday. Southerly winds are expected ahead of the
associated cold front. Showers and thunderstorms are expected
through late tonight and again Tuesday afternoon and evening.
The cold front will cross Lake Michigan early Wednesday morning
and the widespread showers and storms will end. Winds will veer
westerly and scattered showers are possible each afternoon
through the weekend. Winds may approach Small Craft Advisory
criteria at times during this period. Westerly winds continue
through the end of the week as low pressure over south central
Canada weakens.

Cronce/MH

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Flood Watch...WIZ056-WIZ057-WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-
     WIZ064-WIZ065-WIZ066-WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-
     WIZ072 until 4 AM Tuesday.

LM...None.
&&

$$

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