A developing thunderstorm merged with an outflow boundary from another thunderstorm to produce a waterspout about 16 miles southeast of Port Washington. The waterspout lasted for 5 to 10 minutes per estimates from radar.
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The episode as NWS MKX wrote it up.
A developing thunderstorm merged with an outflow boundary from another thunderstorm to produce a waterspout about 16 miles southeast of Port Washington. The waterspout lasted for 5 to 10 minutes per estimates from radar.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Milwaukee, WI wrote its last area forecast discussion before the first event at Aug 10, 1:36 PM CST, 3 hours 29 minutes earlier.
Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 235 PM CDT THU AUG10 2017 .TONIGHT AND FRIDAY - Forecast Confidence...High. Showers and storms are beginning to fire this afternoon as expected. Storms will be likely into early evening, with some of the storms possibly reaching severe levels. Large hail and damaging winds are the main threats. After storms exit the southeast this evening, dry weather is expected overnight. Could see a shower or sprinkle tomorrow as the cooler air aloft moves through, but most places will remain dry. Below normal temps are likely on Friday, with mostly cloudy skies lingering much of the day and the cooler airmass aloft moving through. .FRIDAY NIGHT THROUGH SUNDAY - Forecast Confidence...Medium to High. A mainly dry and comfortable period is expected. Lingering low to mid level cyclonic curvature on Saturday will fight against a very dry atmosphere, so only expecting few-sct cumulus redevelopment. Hence expecting a mostly sunny day with 925H temps resulting in daytime temps warming to slightly below seasonal normal. Weak warm air advection ahead of a slowly moving upper level wave in the northern Plains may clip far southwest Wisconsin with a few showers or storms Sunday afternoon. Otherwise, a bit more cloudiness can be expected on Sunday due to the proximity of the upstream short wave. Temperatures on Sunday will be similar to Saturday. .EXTENDED PERIOD... SUNDAY NIGHT THROUGH THURSDAY - Forecast Confidence...Medium to High. Most of this period is looking dry and seasonal for mid-August. Persistent down-stream low pressure troffing over eastern Canada into the eastern Great Lakes will result in dry NNW steering flow across the western Great Lakes. Upstream, short wave high pressure ridging will gradually expand in coverage and intensity and spread into the western Great Lakes early next week. 925H temps look seasonal with readings in the 15-18 degree range and resultant daytime temperatures warming into the 70s to around 80. Protective ridge should keep southern WI dry at least through Wednesday. Medium range guidance in reasonable agreement showing ridge flattening out due to strong short wave moving ENE through the northern plains into the western Great Lakes around mid-week. GFS Ensembles show some variation in the timing of the short wave trof with several perturbations holding onto lingering ridging. GFS increase precipitable water rapidly to around 2 inches Wednesday night into early Thursday. For now wl include chance pops Wednesday night into Thursday. && .AVIATION(18Z TAFS)...Thunderstorms are likely this afternoon into early evening. The main focus will be across the southeast half of the forecast area. A few of the storms could reach severe levels, with damaging winds and large hail the main threats. After storms exit the southeast this evening, dry weather is expected overnight. Could see a shower or sprinkle tomorrow, but most places will remain dry. Lower ceilings are likely later tonight into Friday as cooler air aloft moves into the area. && .MARINE...Waves could approach 4 feet through late afternoon north of Port Washington under breezy south winds. Otherwise, winds and waves are expected to stay below Small Craft Advisory levels the next several days. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. TONIGHT AND FRIDAY/AVIATION/MARINE...DDV FRIDAY NIGHT THROUGH THURSDAY...MBK
Hazardous Weather Outlook National Weather Service Milwaukee/Sullivan WI 254 PM CDT Thu Aug 10 2017 WIZ046-047-051-052-056>060-062>072-112000- Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge- Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee- Lafayette-Green-Rock-Walworth-Racine-Kenosha- 254 PM CDT Thu Aug 10 2017 This Hazardous Weather Outlook is for portions of east central Wisconsin, south central Wisconsin, and southeast Wisconsin. .DAY ONE...Late this Afternoon and Tonight Numerous thunderstorms will rumble across south central and southeast Wisconsin late this afternoon and this evening. A few thunderstorms will likely become severe, producing large hail and/or damaging thunderstorm wind gusts. One or two tornadoes are also possible. A Severe Thunderstorm Watch is in effect for most of south central and southeast Wisconsin until 9 pm CDT. There is a moderate swim risk late this afternoon into this evening for Sheboygan and Ozaukee beaches adjacent to Lake Michigan. Breaking waves and currents are expected. Stay away from dangerous areas like piers, breakwalls and river outlets. .DAYS TWO THROUGH SEVEN...Friday through Thursday There is a small chance for thunderstorms Wednesday night and Thursday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening. LMZ643>646-112000- 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- 254 PM CDT Thu Aug 10 2017 This Hazardous Weather Outlook is for portions of Lake Michigan. .DAY ONE...Late this Afternoon and Tonight Numerous thunderstorms will affect the near shore waters into this evening. A few thunderstorms may become severe, producing damaging wind gusts and large hail. A Severe Thunderstorm Watch is in effect until 9 pm CDT. .DAYS TWO THROUGH SEVEN...Friday through Thursday There is a chance of thunderstorms next Wednesday night and Thursday. www.weather.gov/mkx MBK
Special Weather Statement National Weather Service Milwaukee/Sullivan WI 445 PM CDT THU AUG 10 2017 WIZ057-058-063-064-102215- Dodge-Columbia-Jefferson-Dane- 445 PM CDT THU AUG 10 2017 ...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN DANE AND NORTHWESTERN JEFFERSON COUNTIES... At 445 PM CDT, a strong thunderstorm was located over northeastern Madison, moving east at 20 mph. Wind gusts up to 50 mph and dime size hail are possible with this storm. Locations impacted include... Eastern Madison, Sun Prairie, Waunakee, Monona, Windsor, Marshall, Waterloo, Cottage Grove, Deerfield, Deansville, Token Creek and East Bristol. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. LAT...LON 4304 8933 4320 8940 4330 8904 4306 8894 TIME...MOT...LOC 2145Z 255DEG 18KT 4314 8931 MBK
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
455 PM CDT THU AUG 10 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0441 PM HAIL WAUPUN 43.63N 88.74W
08/10/2017 E1.00 INCH DODGE WI PUBLIC
MULTIPLE PICTURES RELAYED VIA SOCIAL MEDIA.
&&
BSHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
512 PM CDT THU AUG 10 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0441 PM TSTM WND DMG PLYMOUTH 43.75N 87.97W
08/10/2017 SHEBOYGAN WI LAW ENFORCEMENT
SEVERAL TREES DOWNED.
&&
BSHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
521 PM CDT THU AUG 10 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0448 PM TSTM WND GST SHEBOYGAN 43.75N 87.70W
08/10/2017 M41 MPH LMZ643 WI C-MAN STATION
MEASURED AT SHEBOYGAN LAKESHORE WEATHER
STATION.
&&
MBKSpecial Weather Statement
National Weather Service Milwaukee/Sullivan WI
521 PM CDT THU AUG 10 2017
WIZ060-102245-
Ozaukee-
521 PM CDT THU AUG 10 2017
...A STRONG THUNDERSTORM WILL AFFECT CENTRAL OZAUKEE COUNTY...
At 521 PM CDT, a strong thunderstorm was located over Port
Washington, moving northeast at 30 mph.
Winds in excess of 40 mph and half inch hail are possible with this
storm.
Locations impacted include...
Grafton, Port Washington and Saukville.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 4345 8781 4341 8785 4338 8786 4338 8787
4330 8789 4327 8791 4341 8801 4349 8780
TIME...MOT...LOC 2221Z 245DEG 25KT 4336 8787
MARQUARDTSpecial Weather Statement
National Weather Service Milwaukee/Sullivan WI
529 PM CDT THU AUG 10 2017
WIZ051-052-058>060-102300-
Dodge-Sheboygan-Ozaukee-Washington-Fond Du Lac-
529 PM CDT THU AUG 10 2017
...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHERN OZAUKEE...
SOUTHERN FOND DU LAC...NORTHERN WASHINGTON...SOUTHERN SHEBOYGAN AND
NORTHEASTERN DODGE COUNTIES...
At 528 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Plymouth to near Theresa. Movement
was east at 35 mph.
Winds in excess of 40 mph and dime size hail are possible with these
storms.
Locations impacted include...
Sheboygan, Waupun, Plymouth, Sheboygan Falls, Mayville, Kewaskum,
Oostburg, Lomira, Belgium, Kohler, Cedar Grove, Campbellsport, Random
Lake, Theresa, Oakfield, Ashford, Byron, Eden, Cascade and
Brownsville.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 4356 8779 4348 8780 4350 8858 4362 8893
4374 8819 4374 8771 4370 8770
TIME...MOT...LOC 2228Z 259DEG 29KT 4372 8805 4355 8846
MARQUARDTThe Milwaukee radar (KMKX), 79 km away, was scanning. The volume nearest the first event began at 23:05 UTC.
1 waterspout. Local standard time, as filed.
Public took a photograph of a waterspout on Lake Michigan. The start and end times and path length of the waterspout are estimated from radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Lake Michigan in 2017Every state in 2017This day in weather history
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 706211.