NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 270525
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1225 AM CDT Mon Jul 27 2026

.KEY MESSAGES...

- Additional heat headlines will heavily depend upon the
  coverage and timing of arrival of a thunderstorm complex
  Monday morning.

- The arrival of a line of severe storms has been delayed into
  the morning hours on Monday.

- Late Monday, a cold front will bring final chances for
  storms. All hazards are possible with this activity, but
  intensity will depend on how late storms linger Monday
  morning.

- High swim risk conditions are expected to develop early
  Tuesday morning and continue into Wednesday morning along all
  Lake Michigan beaches due to high waves and currents expected.
  A Beach Hazard Statement has been issued for all Lake Michigan
  counties.

&&

.SHORT TERM...
Issued 1126  CDT Sun Jul 26 2026

Current Overnight through Monday:

Convection has broadly formed in an arc from North-central
Wisconsin to the Arrowhead region of Minnesota this evening as
the low level jet has kicked in. CAMs have handled this
convection very poorly, with recent runs of the CAMs killing
convection shortly after initialization, which doesn't reflect
reality. Based upon observations and MesoA, the low level jet
should sustain convection this morning, with some potential for
the current storms over Waupaca County to make it south into
our area over the next few hours. A larger MCS would then likely
come through some time later near dawn today. All hazards remain
possible, as the environment is marked by steep mid level lapse
rates near 8 C/km, bulk shear > 40 knots, and MUCAPE greater
than 3500 J/kg.

Depending upon how long storms linger this morning and how much
cloud cover stays behind, heat concerns this afternoon may be
lessened. Have held off on a heat advisory at this time given
the uncertainty with storm timing this morning. If storms come
through earlier this morning and clear by late morning, a last
minute heat advisory may be needed, primarily over the western
half of the CWA where heat indices may reach 100 to 102.

One final chance for severe weather may present itself late this
afternoon as a cold front moves through and interacts either
with the lake breeze or whatever remnant outflow boundary is
left behind from this morning's MCS. CAMs depict steep lapse
rates lingering, promoting MUCAPE around 3000 J/kg and
effective shear of 40 knots, and a supercellular mode. Gusty
winds and hail would be the primary threats, though a brief
tornado can't be ruled out if a storm were to ingest the lake
breeze or the left over OFB over southern WI.

CMiller

&&

.LONG TERM...
Issued 1218 AM CDT Sun Jul 26 2026

Monday Night through Saturday:

The mid level shortwave trough will begin to deepen as it gets
over the lower Great Lakes late Monday night. This will usher a
period of gusty northerly winds down Lake Michigan, that will
arrive and push inland from Sheboygan beginning around midnight.
Cooler and drier air will arrive in the wake of this cold front.
Highs Tuesday will be in the upper 70s near Lake Michigan to the
lower 80s inland. Dewpoints will drop into the upper 50s to
around 60 by late afternoon. Lows Tuesday night will be in the
upper 50s to lower 60s, and patchy fog looks possible.

With persistent north-northeast winds along the lakeshore, a high
swim risk will develop for all of the lakeshore counties from
Sheboygan to Kenosha due to waves of 4 to 6 feet. A Beach Hazards
Statement was issued. This runs for a long time, from late Monday
night through late Wednesday morning. High pressure will take hold
and help winds and waves diminish Wednesday, and the headline may
be able to be canceled a little early.

Highs Wednesday will be around 80 near the lakeshore and mid 80s
inland. Areas toward central WI could see upper 80s once again as
the warm and moist ridge starts to push back into the region. By
Wednesday evening, we will be back in an unsettled weather
pattern. A shortwave rounding the ridge over MN and northern WI
Wed nt could generate upstream storms, but the chance of it
pushing all the way into southern WI is low due to the surface
ridge directly overhead. The upper ridge will push into southern
WI on Thursday, giving us highs in the upper 80s and heat indices
in the lower 90s.

Another shortwave will ride over the ridge in the Northern Plains,
but amplify as it crosses the Upper Great Lakes on Friday. There
is fair consensus between the GFS and ECMWF with this feature.
This will bring us a chance for showers and a few storms, but
there is a lower probability for severe. The trough will slowly
exit Wisconsin Saturday, with shower chances lingering until then.
High temperatures Friday through the weekend should be in the
lower 80s.

Cronce

&&

.AVIATION...
Issued 1223 AM CDT Sun Jul 26 2026

Patchy fog is possible this morning amid the high surface dew
points. While its not expected to be dense, vis down to 1 mile
may occur in spots. MVFR to VFR is expected, with increasing
chances for storms near daybreak. All severe weather hazards
will be possible with storms that move through. Following
storms, VFR conditions should return, with some more chances
scattered storms late today.

CMiller

&&

.MARINE...
Issued 1225 AM CDT Sun Jul 26 2026

Patchy dense fog is expected in portions of the central to
northern Lake Michigan through tonight and potentially Monday as
warm moist air moves northward.

Severe storms are possible during the early morning hours within
that warm air mass across Lake Michigan. Waterspouts, very strong
winds, and hail are possible with these storms. Storms will move
north to south across the lake late tonight. Monday, expecting a
cold front to progress north to south across the lake in the
afternoon hours. This will bring the next chances for severe
weather, with strong winds and hail the main threats. Northerly
winds are expected behind the front, with gusts around 30 kt
expected. Gusts to gale force cannot be ruled out as low pressure
deepens over the eastern Great Lakes Tuesday. Locally, a Small
Craft will persist through this time of high winds and waves.

Windswill remain northerly through Wednesday as high pressure
builds into the northern Great Lakes, then will become lighter
and more variable into Thursday and Friday as high pressure
builds overhead.

CMiller

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066-WIZ071-
     WIZ072...midnight Tuesday to 10 AM Wednesday.

LM...None.
&&

$$

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