Severe Thunderstorm Warning 86, NWS Milwaukee, WI

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
342 PM CDT Wed Jun 28 2017

.SHORT TERM...

Tonight...Forecast Confidence is Medium.

There is a round of thunderstorms across south central and
southeast WI right now. These are fueled by persistent warm air
advection and strong moisture transport. The ML CAPE is on the
rise and storms are starting to get a little more height to them.
Still not tall enough for severe. The storms moving into southeast
WI actually has sunshine, so that will help sustain them as they
move through.

The next round of thunderstorms approaching from IA will have the
potential to be severe. These should arrive in Madison around 5 to
6 pm. However, the low clouds that are hanging around all day are
not helping the instability situation and these storms may just
be a large multi-cell cluster by the time they reach south central
WI. Time will tell.

More storms could move through southern WI as late as midnight,
but these have a much lower chance of being severe.

Thursday through Sunday...Forecast confidence medium.

A low pressure area will move across the nrn Great Lakes and
Ontario, Canada for Thu-Thu nt while its trailing cold front
slowly moves across srn WI. Meanwhile a shortwave trough will
approach from the wsw on Thu bringing another round of convection
to far srn WI Thu aft-eve.

As the front drops swd into IL and Lower MI late Thu nt into Fri,
another shortwave trough and wave of low pressure will track
along the front bringing yet another round of convection for much
of srn WI, heaviest in se WI.

On Sat, wnwly flow will prevail with a weak cold front for the
afternoon and evening with isolated to sct tstorm development
possible. A weak ridge of high pressure will follow late Sat nt
into Sun.

Temps and humidity during this period will be near seasonal
normals.

.LONG TERM...Monday through Wednesday...Forecast confidence low.

The models differ on the overall evolution of the synoptic pattern
and a wavering frontal boundary. Chances of showers and storms
will continue with the possibility of a stationary front in the
vicinity of srn WI.

&&

.AVIATION(18Z TAFS)...

Ceilings will gradually improve from west to east this afternoon
as we get better mixing and more heating. Plan on gusty southerly
winds as well.

We are still expecting a couple more rounds of thunderstorms.
There will be some scattered storms through late afternoon, then a
larger area of storms should approach south central WI late this
afternoon which could be severe. There is yet another chance for
storms during the evening hours which could also be strong.

&&

.MARINE...

The increasing southerly winds are delayed this afternoon due to
the morning showers, but they are starting to come up now. Winds
and waves will remain high through much of the night. A small
craft advisory is in effect.

Westerly wind gusts will approach small craft advy levels Thu
afternoon.

&&

.BEACHES...

A Beach Hazard Statement is in effect from Port Washington to
Sheboygan. Breezy southerly winds and high waves will bring a
high swim risk to the Sheboygan county beaches. Winds will be a
bit more off shore and waves will be lower south of that area.
However, a moderate swim risk covers all of southeast Wisconsin
Lake Michigan beaches.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement through late tonight for WIZ052.

LM...Small Craft Advisory until 6 AM CDT Thursday for LMZ643>646.

&&

Tonight/Thursday and Aviation/Marine...Cronce
Thursday Night through Wednesday...Gehring

Hazardous Weather Outlook...UPDATED
National Weather Service Milwaukee/Sullivan WI
526 PM CDT Wed Jun 28 2017

WIZ046-047-051-052-056>060-062>072-291200-
Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
526 PM CDT Wed Jun 28 2017

This Hazardous Weather Outlook is for portions of east central
Wisconsin, south central Wisconsin, and southeast Wisconsin.

.DAY ONE...Tonight

A Tornado Thunderstorm Watch is in effect for most of southern
Wisconsin through late evening. Storms will produce heavy rain and
may produce damaging winds, large hail, or a tornado.

A small threat of flash flooding also exists as some areas may
see repeated rounds of thunderstorms and heavy rain.

A Beach Hazard Statement is in effect into tonight for beaches in
Sheboygan County. Breezy southerly winds and high waves will
result in dangerous rip, structural, and longshore currents.

.DAYS TWO THROUGH SEVEN...Thursday through Wednesday

Thunderstorms are possible at times from Friday through Tuesday as
multiple low pressure systems move through the region.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will be needed Tonight.

LMZ643>646-291200-
Sheboygan to Port Washington WI-
Port Washington to North Point Light WI-
North Point Light to Wind Point WI-
Wind Point WI to Winthrop Harbor IL-
526 PM CDT Wed Jun 28 2017

This Hazardous Weather Outlook is for portions of Lake Michigan.

.DAY ONE...Tonight

A Small Craft Advisory is in effect through tonight due to breezy
southerly winds and high waves.

Thunderstorms are likely late through late evening. Some of these
storms may be severe during this time.

.DAYS TWO THROUGH SEVEN...Thursday through Wednesday

Thunderstorms are possible at times from Friday through Tuesday
as multiple low pressure systems move through the region.

Cronce

www.weather.gov/mkx