Severe Thunderstorm Warning 107, NWS Milwaukee, WI

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
310 PM CDT Wed Jun 19 2024

.KEY MESSAGES...

- Scattered showers and storms are forecast into early this
  evening for most of southern Wisconsin. May see gusty winds
  with the stronger storms over southeast Wisconsin. On and off
  thunderstorm chances will then continue into this weekend.

- Heat index values will be in the middle 90s over southeast
  Wisconsin until early this evening. Head index values will be
  back in the middle 90s Friday and Saturday.

- A moderate swim risk may occur Thursday morning at Sheboygan
  County beaches.

&&

.SHORT TERM...
Issued 310 PM CDT Wed Jun 19 2024

Tonight through Thursday night:

Cold front will continue to shift southeast through the area and
into northern Illinois into this evening. Scattered showers and
storms continue to develop and slowly shift northeast through
parts of the area, both near the front and where convective
temperatures may be reached. CAMs continue to support the
scattered showers and storms into early this evening across the
area.

The best instability will be toward southeast Wisconsin, where
mean layer CAPE up to 1500 J/kg or so is expected, perhaps
higher in spots. Areas further northwest may have more clouds
move in with the front, so mean layer CAPE there will be lower.
0 to 6 km bulk shear values should increase by early evening
into the 20 to 25 knot range, though the southeast parts of the
area will be on the lower end of this range.

This would mean short-lived airmass thunderstorms that have
some downburst wind potential, as forecast soundings are showing
some inverted V structures to them in the low levels. In
addition, cannot totally rule out a landspout spinup, as 0 to 3
km CAPE values are above 100 J/kg along the front and are
coinciding with some surface vorticity with the front. The
probability is low, but not zero. We will keep an eye on this.

Heat index values in the lower to middle 90s are expected to
linger in southeast Wisconsin until early this evening. Cooler
but still mild temperatures are expected later tonight into
Thursday, as winds shift northeast and lower clouds move in.
Some fog and low stratus clouds may also push onshore near the
lake overnight into Thursday morning. The clouds may linger for
a good part of Thursday.

Chances for showers and storms will continue at times overnight
into Thursday night, as some modest 850 mb warm air advection
and convergence/frontogenesis response lingers near the area.
Areas near the Illinois border may see the best chances for
storms Thursday afternoon and evening, as some better low level
frontogenesis with the front just to the south of the area
interacts with warm and unstable air. May see some gusty winds
with any of those storms as well.

&&

.LONG TERM...
Issued 310 PM CDT Wed Jun 19 2024

Friday through Wednesday:

Models are generally showing the warm front shifting north
across the area Friday into Friday night, before moving further
north for Saturday. Chances for showers and storms will remain
during this period. The area should get into the warm sector and
become very warm and humid again on Saturday with southwest
winds. A cold front looks to shift east across the region
Saturday night, bringing another chance for showers and
thunderstorms. Will have to watch this period for stronger
storms, though deep layer bulk shear values are only 20 to 25
knots at this time.

There may be a lull in precipitation chances Sunday into Monday,
as high pressure may move through the region. Temperatures look
to remain near to above normal into next week per ensemble
trends. Chances for showers and storms may return for the middle
of next week as well, as ensembles are showing a generally wet
Tuesday into Wednesday period.

Wood

&&

.AVIATION...
Issued 310 PM CDT Wed Jun 19 2024

Scattered showers and storms are expected to continue into early
this evening, as a cold front moves southeast through the area.
Gusty winds are possible with the storms, with locally reduced
visibility values.

Gusty southwest winds ahead of the front will shift west to
northwest and weaken by early this evening, as the cold front
moves through. Winds will then shift north by later this
evening and northeast later tonight, with east to northeast
winds on Thursday.

Cooler temperatures are expected tonight into Thursday,
especially near Lake Michigan. Some showers and storms may
occur at times overnight into Thursday night, perhaps more
toward the Illinois border areas on Thursday.

General VFR ceilings into this evening should drop to 500 to
1200 feet AGL Thursday morning, as low stratus clouds move into
the area off of Lake Michigan. These ceilings should slowly
rise Thursday afternoon. In addition, fog with 2 to 5 mile
visibility may form overnight into Thursday morning, with some
fog moving onshore from Lake Michigan for terminals near the
lake. Locally lower values are possible.

Wood

&&

.MARINE...
Issued 310 PM CDT Wed Jun 19 2024

A cold front will gradually sink southeast across Lake Michigan
into tonight. South to southwest winds will shift northwest to
north this evening, and northeast to north later tonight into
Thursday. Patchy to areas of marine fog may form tonight and
linger into Thursday morning, with some dense fog possible.

North to northeast winds should then linger into Friday, as high
pressure around 30.4 inches moves from Lake Superior into Ontario.
Gusty south to southwest winds are then anticipated to return for
Saturday into Saturday night, as low pressure around 29.5 inches
shifts into the region.

Wood

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

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Hazardous Weather Outlook...UPDATED
National Weather Service Milwaukee/Sullivan WI
228 PM CDT Wed Jun 19 2024

WIZ046-047-051-052-056>060-062>072-201930-
Marquette-Green Lake-Fond du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
228 PM CDT Wed Jun 19 2024

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

.DAY ONE...Late This Afternoon and Tonight

Scattered thunderstorms capable of gusty winds may occur into
early this evening. Chances for storms may linger overnight.

Heat index values in the middle 90s will occur over southeast
Wisconsin until early evening.

.DAYS TWO THROUGH SEVEN...Thursday through Wednesday

A moderate swim risk may occur at Sheboygan County beaches
Thursday morning.

There are chances for thunderstorms at times into this weekend.

Heat index values in the middle 90s may occur Friday and Saturday
over parts of southern Wisconsin.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

LMZ643>646-201930-
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-
228 PM CDT Wed Jun 19 2024

This Hazardous Weather Outlook is for the nearshore waters from
Sheboygan Wisconsin to Winthrop Harbor Illinois.

.DAY ONE...Late This Afternoon and Tonight

Scattered thunderstorms capable of gusty winds may occur into
early this evening. Chances for storms may linger overnight.

Dense fog may develop tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Wednesday

Dense fog may linger into Thursday morning.

There are chances for thunderstorms at times into this weekend.

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-201930-
Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to
mid-line of lake.-
Lake Michigan from Seul Choix Point to Rock Island Passage 5NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and North of a line from Charlevoix MI to South
Fox Island 5NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to
mid lake-
Lake Michigan from Point Betsie to Manistee MI 5NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI 5NM
offshore to mid lake-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5NM offshore to Mid
Lake-
Lake Michigan from Sheboygan to Port Washington WI 5NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor to Michigan City in 5NM
offshore to Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid
Lake-
Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5NM offshore to Mid
lake-
Lake Michigan from St Joseph to South Haven MI 5NM offshore to
Mid Lake-
228 PM CDT Wed Jun 19 2024

This Hazardous Weather Outlook is for the open waters of Lake Michigan.

.DAY ONE...Late This Afternoon and Tonight

Scattered thunderstorms capable of gusty winds may occur into
early this evening. Chances for storms may linger overnight.

Dense fog is possible tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Wednesday

Dense fog may linger into Thursday.

There are chances for thunderstorms at times into this weekend.

Wood
www.weather.gov/mkx

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
300 PM CDT Wed Jun 19 2024

WIZ057-058-063-192030-
Dodge WI-Columbia WI-Dane WI-
300 PM CDT Wed Jun 19 2024

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN COLUMBIA...
NORTHEASTERN DANE AND WESTERN DODGE COUNTIES THROUGH 330 PM CDT...

At 259 PM CDT, Doppler radar was tracking a strong thunderstorm near
Columbus, moving northeast at 25 mph.

HAZARD...Wind gusts up to 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Beaver Dam, Columbus, Marshall, Horicon, Juneau, Fall River, Burnett,
Fox Lake, Reeseville, Lowell, Deansville, Atwater, Danville, South
Beaver Dam, Minnesota Junction, and Leipsig.

This includes the following highways...
 U.S. Highway 151 between mile markers 110 and 142.
 Wisconsin Highway 26 near mile marker 53.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4340 8857 4316 8911 4336 8916 4363 8882
      4363 8878
TIME...MOT...LOC 1959Z 232DEG 23KT 4338 8892

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

MRC