Flash Flood Warning 13, NWS Milwaukee, WI

406 
WGUS73 KMKX 180259
FFSMKX

Flash Flood Statement
National Weather Service Milwaukee/Sullivan WI
959 PM CDT Fri Apr 17 2026

WIC055-079-101-127-133-180309-
/O.CAN.KMKX.FF.W.0013.000000T0000Z-260418T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson WI-Milwaukee WI-Racine WI-Walworth WI-Waukesha WI-
959 PM CDT Fri Apr 17 2026

...FLASH FLOOD WARNING FOR MILWAUKEE, NORTHWESTERN RACINE, 
NORTHEASTERN WALWORTH AND WAUKESHA COUNTIES HAS BEEN REPLACED WITH A 
FLOOD WARNING...
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN JEFFERSON 
COUNTY...

&&

LAT...LON 4292 8854 4300 8847 4308 8830 4315 8789
      4313 8790 4307 8787 4304 8790 4303 8790
      4300 8789 4299 8787 4296 8785 4291 8784
      4289 8785 4288 8790 4279 8828 4271 8862
      4281 8849 4284 8850 4284 8854

$$

KUROSKI

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
711 PM CDT Fri Apr 17 2026

.KEY MESSAGES...

- Thunderstorms with higher-end severe potential and heavy
  rainfall is expected into early evening. An Enhanced Risk (3
  out of 5) for severe weather exists over the western half of
  the CWA. Heavy rain over saturated ground may lead to flash
  flooding.

- A Flood Watch in effect for all of southern Wisconsin until
  7am Saturday.

- Marine Dense Fog continues through tonight.

&&

.UPDATE...
Issued 711 PM CDT Fri Apr 17 2026

Severe storm threat will continue across the southeast half of
the forecast area over the next 2-3 hours. All severe hazards
remain possible along with flash flooding due to already
saturated soils.

After a brief break in precip, will see isolated to scattered
storms along the cold front later this evening into tonight.
Storms are generally expected to be sub severe, with up to
0.25" of additional rain with this last round.

DDV

&&

.SHORT TERM...
Issued 1207 PM CDT Fri Apr 17 2026

Tonight and Saturday:

Nearly all of southern WI has sunshine as of 1130 this morning.
The fog and low stratus are hanging on over east central WI, but
the increasing southerly winds will help that to erode quickly
through the early afternoon. Temperatures are rising quickly,
with areas west of Madison already in the lower 70s. Dewpoints
are rising as well, with lower 60s in the southwest. Gusty winds
are developing as we start to mix out our low layer inversion
and diurnal cu are also popping up. This is all conducive for
priming our environment for convection this afternoon.

The main change for today is that we are expecting storms to
develop and move into southwest WI earlier than forecast, now
between 1 and 5 PM. Storms triggered along a gravity wave just
south of the Twin Cities around 8 am. If we trace that gravity
wave down into Iowa on satellite, the cumulus clouds are
focusing along it. The leading edge of this is now entering
northeast IA and far southeast MN. The timing of it to arrive
in Madison is 230PM/1930Z, give or take a half hour. There is no
lighting in eastern IA yet, but we are watching for that to
happen within the next 30 to 60 minutes.

Whatever develops in IA and tracks eastward is our main show in
southern WI for today. All hazards are on the table. High CAPE,
shear and helicity all point to a large hail (greater than 2
inches), damaging wind and tornado potential. If tornadoes
develop, they would be on the strong side. As any discrete cells
congeal into a line as they head into eastern WI, the severe
threat will be mainly for damaging wind and QLCS tornadoes. With
0 to 3 km shear vectors up to 50 kt and aligned perpendicular
to the line of storms (and streamwise vorticity of 45-50 kt),
brief spin- up tornadoes are favorable along the leading edge
within any notches/bowing line segments.

There is still a chance that the storms that develop in Iowa
could skirt just to the south of WI and be the strongest across
northern IL this afternoon. If I had to guess, the strongest
storms should be over the south half of southern WI. However,
there is still a severe threat for all of WI, including north
central all the way to Green Bay.

The actual cold front is back in south central MN and central
IA. This is a very strong front, with over a 20 degree temp drop
behind it. Storms will be well ahead of the front, but once our
afternoon storms clear, we will still have a chance for
scattered showers and thunderstorms (not severe) until the
actual front passes during the late evening and overnight hours.

Cronce

&&

.LONG TERM...
Issued 244 PM CDT Fri Apr 17 2026

Saturday through Friday:

Gusty west-northwest winds up to 30 mph are expected behind the
cold front Saturday. Sunshine should be prevalent, although
cyclonic flow aloft will allow for some high-level diurnal
cumulus clouds. Saturday highs will only be in the 40s, a stark
contrast to the highs today. Lows Saturday night should dip
below freezing nearly everywhere except the immediate Lake
Michigan lakeshore.

The upper low will remain over Ontario Sunday and a shortwave
trough digging into central and southern WI may steepen lapse
rates enough to produce a few flurries. It looks like moisture
will be very limited with this feature, but the forcing is
certainly there. Highs Sunday will be similar to Saturday but
with slightly lighter northwest winds. Lows Sunday night have a
better chance of dropping below freezing, with lows forecast in
the 25 to 30 degree range.

As high pressure departs the Upper Great Lakes on Monday,
southerly winds will usher milder air back into southern WI.
The sunshine will also help temps get into the mid 50s inland
and lower 50s near the lakeshore. A clipper system will cross
Ontario and Lake Superior Monday night, but southern WI will
remain dry. However, this could push a cold front down Lake
Michigan Tuesday. Not all models have picked up on this
potential yet, so the forecast highs Tue are in the lower 70s
inland and mid 60s lakeshore. Lakeshore temps could end up being
colder, but the highs will depend on when that back door cold
front actually makes it onshore.

There will be a stark temp gradient across southern WI from
west to east on Wednesday as low pressure develops in the
Plains. It looks like the storms associated with the warm front
of this low will be over northeast MN and northern WI Thu. All
We should see temps get back into the upper 70s inland over
southern WI. The next potential for showers and thunderstorms,
potentially severe, looks like next week Friday.

Cronce

&&

.AVIATION...
Issued 711 PM CDT Fri Apr 17 2026

Severe storm threat will continue across the southeast half of
the forecast area over the next 2-3 hours. All severe hazards
remain possible along with flash flooding due to already
saturated soils.

After a brief break in precip, will see isolated to scattered
storms along the cold front later this evening into tonight.
Storms are generally expected to be sub severe, with up to
0.25" of additional rain with this last round.

Lower ceilings and visibilities are likely within any
thunderstorms into tonight. Widespread low clouds (700-1200 ft) are
then expected behind the cold front later this evening into
tonight, with breezy west to northwest winds gusting 25 to 30
knots.

Skies should clear out west to east Sat morning, with gusty west
to northwest wind gusts to 30 knots continuing through the day.

DDV

&&

.MARINE...
Issued 1207 PM CDT Fri Apr 17 2026

Winds will become southerly this morning as a surface low of 29.5
inches approaches from the central plains. Dense fog will
continue over the lake through this evening and likely during
the overnight hours until the cold front clears the lake. This
surface low will quickly move from Omaha to Duluth from this
morning into the afternoon. Winds will become gusty and
southeasterly tonight, and strong to severe storms will cross
the lake as a cold front sweeps through the area. Winds then
become northwesterly behind the cold front Saturday morning.
Breezy northwesterly winds then continue Saturday through Sunday
as the low then races northeast toward Hudson Bay. Winds ease
Monday morning as high pressure tracks southeast over the upper
Great Lakes.

Cronce

&&

.HYDROLOGY...Issued 1207 PM CDT Fri Apr 17 2026

This afternoon / evening's convection is expected to produce an
additional 0.50 to 1.25 inches of rainfall across the region,
with locally higher totals up to 2.00 inches possible. Probs of
exceeding 2.00 are only 10% or less based off of most guidance.
Highest rainfall potential exists in the western half of the
CWA, given the potential for initial supercells with heavy rain
followed by additional showers / storms along the advancing cold
front (eg. multiple rounds of heavier precip). Further east,
still expecting a good burst of heavy rain from short line
segments or QLCS to be more progressive / fast- moving by that
time of day, but increased the storm total amounts toward an
inch.

Cronce/Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Flood Watch...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-WIZ058-
     WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-WIZ067-
     WIZ068-WIZ069-WIZ070-WIZ071-WIZ072 until 7 AM Saturday.

LM...Dense Fog Advisory...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
     LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
     LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until 4 AM
     Saturday.

     Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 10 PM
     Saturday.

&&

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Hazardous Weather Outlook
National Weather Service Milwaukee/Sullivan WI
256 PM CDT Fri Apr 17 2026

WIZ046-047-051-052-056>060-062>072-182000-
Marquette-Green Lake-Fond du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
256 PM CDT Fri Apr 17 2026

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

.DAY ONE...Rest of Today and Tonight

Thunderstorms with higher-end severe potential and heavy rainfall
is expected this afternoon and early evening. An Enhanced Risk (3
out of 5) for severe weather exists over the western half of the
CWA. Heavy rain over saturated ground may lead to flash flooding.

.DAYS TWO THROUGH SEVEN...Saturday through Friday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will be needed through tonight.

LMZ643>646-182000-
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-
256 PM CDT Fri Apr 17 2026

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

.DAY ONE...Tonight

Dense fog continues for the whole nearshore through the overnight
hours.

Small Craft Advisory in effect for high waves and strong
southerly winds through tonight

Thunderstorms are likely late afternoon and this evening, with
severe storms possible.

.DAYS TWO THROUGH SEVEN...Saturday through Friday

Small Craft Advisory will continue through Saturday evening for
breezy west to northwest winds.

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-182000-
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-
256 PM CDT Fri Apr 17 2026

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

.DAY ONE...Tonight

A few southerly gale force gusts are possible through late
evening.

Dense fog continues through tonight.

Thunderstorms are likely late afternoon and this evening, with
severe storms possible.

.DAYS TWO THROUGH SEVEN...Saturday through Friday

No hazardous weather is expected at this time.

MRC

www.weather.gov/mkx

Preliminary Local Storm Report
National Weather Service Milwaukee/Sullivan WI
633 PM CDT Fri Apr 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0609 PM     Tornado          1 N Avalon              42.65N 88.87W
04/17/2026                   Rock               WI   Public

            Corrects previous tornado report from 5 ENE
            Avalon. Snapped and uprooted trees, damage
            to houses, and sheet metal wrapped around
            trees near Emerald Grove. Time estimated
            from radar.

&&

TP

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
633 PM CDT Fri Apr 17 2026

WIZ051-052-059-060-180030-
Sheboygan WI-Washington WI-Ozaukee WI-Fond Du Lac WI-
633 PM CDT Fri Apr 17 2026

...STRONG THUNDERSTORMS WILL IMPACT OZAUKEE...SOUTHEASTERN FOND DU
LAC...WASHINGTON AND SHEBOYGAN COUNTIES THROUGH 730 PM CDT...

At 633 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Howards Grove to near Random Lake to near
Hartford. Movement was northeast at 45 mph.

HAZARD...Wind gusts up to 50 mph and pea 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...
Sheboygan, West Bend, Mequon, Hartford, Grafton, Cedarburg, Port
Washington, Plymouth, Sheboygan Falls, Jackson, Slinger, Saukville,
Kewaskum, Howards Grove, Germantown, Oostburg, Belgium, Fredonia,
Kohler, and Cedar Grove.

This includes the following highways...
 Interstate 43 between mile markers 93 and 135.
 Interstate 41 between mile markers 54 and 80.
 U.S. Highway 45 between mile markers 61 and 73.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

A Tornado Watch remains in effect until 800 PM CDT for southeastern
and east central Wisconsin.

&&

LAT...LON 4357 8779 4349 8779 4335 8788 4319 8816
      4320 8842 4358 8839 4389 8806 4389 8774
      4381 8773 4376 8770 4368 8770
TIME...MOT...LOC 2333Z 214DEG 37KT 4379 8789 4362 8796 4335 8836

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

WAGNER

Preliminary Local Storm Report
National Weather Service Milwaukee/Sullivan WI
641 PM CDT Fri Apr 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0640 PM     Flood            2 W Janesville          42.68N 89.05W
04/17/2026                   Rock               WI   Broadcast Media

            Two cars stranded in flood waters near North
            Crosby Ave.

&&

TP

Preliminary Local Storm Report
National Weather Service Milwaukee/Sullivan WI
719 PM CDT Fri Apr 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0712 PM     Hail             Eagle                   42.88N 88.47W
04/17/2026  M1.00 Inch       Waukesha           WI   Amateur Radio

            Relayed from HAM Radio.

&&

TP

Preliminary Local Storm Report
National Weather Service Milwaukee/Sullivan WI
728 PM CDT Fri Apr 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0725 PM     Hail             2 S Eagle               42.85N 88.47W
04/17/2026  E1.00 Inch       Waukesha           WI   Amateur Radio

&&

TP

Preliminary Local Storm Report
National Weather Service Milwaukee/Sullivan WI
739 PM CDT Fri Apr 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0702 PM     Hail             3 SE Palmyra            42.83N 88.56W
04/17/2026  E1.00 Inch       Walworth           WI   Public

&&

TP