NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 111227 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
727 AM CDT Thu Jun 11 2026

.KEY MESSAGES...

- Significant severe storms are possible this afternoon and
  evening. Tornadoes, damaging winds, and large hail are all
  possible. There is a small potential for flash flooding
  especially in urban areas.

&&

.UPDATE...
Issued 727 AM CDT Thu Jun 11 2026

The thunderstorms that fired along the nose of the low level jet
in southern NE overnight have evolved into an eastward moving
complex across Iowa this morning. The northern portion of this
complex is expected to clip southern WI. Storms in this area
will likely be elevated and post a threat for small hail. Can't
rule out a since strong storm or two, but no widespread severe
with this round.

Early this afternoon, we can expect numerous storms to develop
in eastern IA and southwest WI as the nose of the low level jet
pushes in and surface low pressure strengthens in central IA and
tracks through central WI. The increasing southerly winds and
low level jet will usher higher instability, very strong shear
(low level and bulk), and high helicity into southern WI. This
very unstable layer should zipper up toward Madison and expand
eastward along I-94. However, there is some uncertainty and it
could remain closer to the IL border (or zip farther north).
Regardless, we have a very good setup for high-end severe storms
with tornadoes, damaging winds and large hail, especially toward
the WI/IL border in south central WI. As the storms track
eastward, they will evolve into a line for a more widespread
damaging wind threat but also tornadoes (due to high 0-3km
shear).

The main message we want to share is that today has a higher
tornado risk than yesterday. Be weather aware, have multiple
ways to receive warnings, and have a plan to take immediate
action if a tornado warning is issued for your location.

Increasing south-southeast winds along the lakeshore and over
southern Lake Michigan this afternoon will bring high waves to
the lakeshore areas between 4 and 11 PM, especially north of
Port Washington. We will briefly have a high swim risk for that
area, but then winds will become offshore as storms are rolling
through between 6 and 9 PM.

Cronce

&&

.SHORT TERM...
Issued 1256 AM CDT Wed Jun 10 2026

Today and tonight:

The thunderstorm east of Monroe will drift into IL early this
morning with only slight chances for redevelopment through
08-09Z. Although the cold front will continue to dissipate west
of the MS River, drier air at 925-850 mb on wly winds will
contribute to the ending of the showers and storms early this
morning. Areas of light fog and low stratus may form early this
morning given the moist conditions and weakening sfc winds.

The potential for significant severe thunderstorms still looks
fairly probable today as low pressure and a vorticity maximum
tracks newd from KS this morning reaching ne IA by 18Z then into
east central WI by 00Z Fri. A strong sswly low level jet of 50
kt will quickly surge nwd ahead of the low bringing a round of
low to mid level warm, moist advection and showers and storms
to srn WI from late morning into the early afternoon. These
storms will likely be elevated with the potential for large
hail. As the sfc low tracks from ne IA to east central WI
accompanied by the trailing cold front, high thetae air will
surge north across srn WI with a MLCAPE gradient from 1000-1500
J/KG over central WI to 2500-3000 J/KG toward the IL border.
Strong deep layer and low level shear will be in place as shown
by large, curved hodographs. CAMs are not surprisingly
highlighting supercells via updraft helicity, but also line
segments with a QLCS as the predominant mode. Isolated
tornadoes, damaging winds, and large hail are all probable
including some significant occurrences of each possible.

Wly winds and cold advection will then prevail in the wake of
the storms this evening. Temps are expected to drop into the 50s
by sunrise Fri.

Gehring

&&

.LONG TERM...
Issued 1256 AM CDT Wed Jun 10 2026

Friday through Wednesday:

Light to modest wly surface winds, dry weather, and near normal
temps will return for Friday in the wake of a cold front Thu nt.
Otherwise zonal flow will prevail into the weekend. A weak
trough in the low to mid levels will approach from the west Sat
afternoon and pass Sat nt. Weak low to mid level warm, moist
advection, but slightly stronger frontogenesis in that layer
will support 60-80 percent chances of showers and thunderstorms.

A larger scale upper trough will then become established over
Ontario early next week including weak shortwave troughs
rotating across the region. This will bring below normal temps
to srn WI, and shower chances of 20-40 percent at times through
Wed.

Gehring

&&

.AVIATION...
Issued 727 AM CDT Thu Jun 11 2026

Stratus with ceilings between 400 and 1400 ft AGL developed in a
strip across southern WI early this morning. There are clear
skies in southeast WI and central WI, but the low ceilings are a
little transient. Expect the MVFR/IFR clouds to diminish around
mid morning, but there is uncertainty here. A complex of
thunderstorms rolling across IA will track into northern IL and
southern WI, with the stronger portion on the IL side. This
should arrive in south central WI around 10 or 11 AM and should
have a diminishing trend to the precip. Did not include it in
the eastern TAF sites at this time.

Severe thunderstorms are likely across south central WI,
especially toward the IL border. All hazards are possible.
Tornadoes/large hail/wind in south central WI and then
wind/tornadoes in southeast and east central WI.

Look for gusty south winds ahead of the storms and gusty west
winds behind them. Winds will diminish overnight as skies clear
out.

Cronce

&&

.MARINE...
Issued 727 AM CDT Thu Jun 11 2026

Modest south to southwest winds can be expected through this
morning but will become breezy south to southeasterly this
afternoon. This will occur as low pressure around 29.5 inches
moves from eastern Iowa to central Lake Michigan by early
evening, then northeast into Ontario by early Friday morning.
Winds will become westerly and breezy behind the low pressure area
this evening into the overnight. Modest to breezy southwest winds
will follow for Friday into Saturday. Numerous thunderstorms are
expected this afternoon and evening and may become severe.

A small craft advisory is in effect from this afternoon through
tonight for wind gusts and elevated waves. Highest waves toward
Sheboygan.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643...4 PM Thursday to 4 AM Friday.

     Small Craft Advisory...LMZ644-LMZ645-LMZ646...4 PM Thursday to
     11 PM Thursday.

&&

$$

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