A low pressure area and warm front resulted in rounds of strong to severe thunderstorms. Damaging winds caused tree damage and some structural damage.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MKX wrote it up.
A low pressure area and warm front resulted in rounds of strong to severe thunderstorms. Damaging winds caused tree damage and some structural damage. Large hail was also observed.
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 May 17, 1:35 PM CST, 10 minutes earlier.
Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 235 PM CDT WED MAY 17 2017 .TONIGHT AND THURSDAY - Forecast Confidence...Medium. The focus through the evening hours will be on the potential for severe thunderstorms. Not much has changed with the setup, with plenty of moisture, instability, and wind flow with strong low pressure approaching from the southwest. The main severe threat through the afternoon hours will be wind/hail. Wind shear will be stronger toward the evening hours, increasing the potential for a tornado threat. Meso models show the western half of the forecast area to have the best potential for storms through the late afternoon and already seeing a few storms in the west. Some questions as to areal extent and coverage of storms through late afternoon, with a couple models showing a farther eastward extent of scattered storms. A more focused line of storms is likely during the evening hours, moving in from the southwest, then spreading eastward by late evening. Models continue to show somewhat of a weakening trend toward Lake Michigan. Storms are expected to wind down by midnight, with a few showers lingering overnight in the northwest toward the low. A round of light showers is possible tomorrow, from mid morning into the afternoon as a cold front drops through the area. Temps will likely cool behind the front from northwest to southeast from late morning into the afternoon. .THURSDAY NIGHT THROUGH SATURDAY - Forecast Confidence...Medium. Showers and t-storms expected to return to southern WI later Friday night into Saturday as upper ridge slides off to the east and low pressure over the southwest fills and gets ejected northeast into the central and northern Plains. Short wave reamplifies and takes on slight negative tilt as it progresses through the northern Plains and re-energizes late in the period. Will continue likely wording for later Friday night into Saturday when axis of strong low level jet passes across southern WI, in rough timing with potential mesoscale convective eddy generated by upstream plains convection. .EXTENDED PERIOD... SATURDAY NIGHT THROUGH WEDNESDAY - Forecast Confidence...Medium. Cooler weather is expected early in the period as the main rain area moves off to the northeast. Differences in extended guidance on the strength and timing of upper low over southern Canada through early next week. However Medium range guidance in somewhat agreement on short wave trof rotating around upper low across the Upper Midwest around Tuesday or Wednesday bringing another chance of showers and storms to the area. && .AVIATION (18Z TAFS)... A couple more rounds of storms are expected this afternoon and evening ahead of approaching low pressure. Some of the storms may be severe. A few showers may linger past midnight, with another round of showers possible tomorrow as the cold front slides through. The showers tomorrow will be on the light side. Low level wind shear looks possible again tonight...from around mid/late evening through late tonight. Outside of lower visibilities in thunderstorms, mainly VFR conditions are expected into tonight. Will likely see lower ceilings tomorrow near and behind the advancing cold front. && .MARINE... Southerly winds will remain gusty through Thursday, veering to the southwest by Thursday morning. With little to no onshore component to the winds, waves should generally stay in the 3 to 5 foot range through Thursday afternoon. After a brief break, will likely see winds/waves pick back up Thursday evening into Friday. Another Small Craft Advisory will probably be needed. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory until 4 PM CDT Thursday for LMZ643>646. TONIGHT AND THURSDAY/AVIATION/MARINE...DDV THURSDAY NIGHT THROUGH WEDNESDAY...MBK
Hazardous Weather Outlook National Weather Service Milwaukee/Sullivan WI 340 AM CDT Wed May 17 2017 WIZ046-047-051-052-056>060-062>072-180845- Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge- Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee- Lafayette-Green-Rock-Walworth-Racine-Kenosha- 340 AM CDT Wed May 17 2017 This Hazardous Weather Outlook is for portions of east central Wisconsin, south central Wisconsin, and southeast Wisconsin. .DAY ONE...Today and Tonight Thunderstorms are likely across south central Wisconsin with a chance of thunderstorms southeast today into this evening. The period of greatest concern for severe thunderstorms is late afternoon into the early evening especially across south central Wisconsin where there is a greater risk of a few tornadoes, large hail and damaging winds. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday There is a chance of thunderstorms again on Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening. LMZ643>646-180845- 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- 340 AM CDT Wed May 17 2017 This Hazardous Weather Outlook is for portions of Lake Michigan. .DAY ONE...Today and Tonight A small craft advisory is in effect for breezy southerly winds. There is a chance of thunderstorms this afternoon and evening. There is a marginal risk of severe thunderstorms. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday A small craft advisory is in effect through Thursday afternoon for breezy southerly winds. There is a chance of thunderstorms again on Saturday. Collar www.weather.gov/mkx
Special Weather Statement National Weather Service Milwaukee/Sullivan WI 216 PM CDT WED MAY 17 2017 WIZ056-057-062-063-171945- Columbia-Iowa-Sauk-Dane- 216 PM CDT WED MAY 17 2017 ...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN IOWA...SOUTHWESTERN COLUMBIA...NORTHWESTERN DANE AND EASTERN SAUK COUNTIES... At 215 PM CDT, a strong thunderstorm was located near Mazomanie, or 11 miles southwest of Sauk City, moving northeast at 40 mph. Winds in excess of 30 mph and pea size hail are possible with this storm. Locations impacted include... Baraboo, Prairie Du Sac, Sauk City, Lake Wisconsin, Lodi, Mazomanie, West Baraboo, Black Earth, Arena, Merrimac, Harmony Grove, Okee and Devils Lake St Park. LAT...LON 4305 8986 4315 9006 4357 8974 4341 8943 TIME...MOT...LOC 1915Z 214DEG 37KT 4317 8990 SPM
The Milwaukee radar (KMKX), 99 km away, was scanning. The volume nearest the first event began at 19:44 UTC.
22 thunderstorm wind, 7 hail. Local standard time, as filed.
Several trees and limbs down including power lines.
Over 200 calls pertaining to tree damage over the eastern two-thirds of the county. Some power lines down. These locations included Beloit, Janesville, Milton and other communities near these cities and east and north to the Walworth and Jefferson County borders.
Trees uprooted landing on a large overhang of a home, thereby collapsing it.
Walls collapsed on several older farm buildings.
A barn lost its roof, an uprooted tree and branches down.
A considerable number of trees and limbs down in Whitewater. Some trees or limbs down on homes and vehicles. Roads were closed due to the large number of trees blocking the roads. No electricity into the next day with schools cancelled. A corn dryer on Howard Road was disconnected from its gas line, thereby causing a fire.
Trees down on the University of Wisconsin Whitewater campus including near Perkins Stadium on the north side of Whitewater in Jefferson County.
Two street light poles down in Fort Atkinson, one downtown and the other on the northwest side of the city. Branches down in the city.
A large uprooted tree landing on a house.
A large tree uprooted.
Numerous trees and limbs down.
Several trees and limbs down along highway 126.
Several trees and limbs down including power lines.
Several trees and limbs down including power lines.
Straight-line winds downed six trees.
Numerous reports of trees and limbs down across the western portion of the county.
A 20 inch diameter tree down.
A few trees and limbs down.
A grain bin was blown over.
A barn blown down and two 2X4s blown into a nearby house.
Numerous large branches down and a few rotten trees snapped. Over 100 square feet of siding removed from a home. A power pole was leaning from the strong winds. Some power lines down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2017Every state in 2017This day in weather historyWarnings in Wisconsin, May 2017
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: 691661, 691643, 691644, 691645, 691770, 691774, 691647, 691773, 691648, 691796, 691813, 691822, 691805, 691810, 691650, 691811, 691829, 691830, 691653, 691654, 691657, 691659, 691665, 691663, 691664, 691666, 691667, 691788, 691651.