A couple rounds of thunderstorms moved across western Wisconsin during the afternoon and evening of July 18th. Most of these storms remain below severe limits, but a couple of storms briefly produced strong enough winds to blow down trees near Fountain City (Buffalo County) and Wonewoc (Juneau County).
Every event with a place to put it. Tap one for its entry below.
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 ARX wrote it up.
A couple rounds of thunderstorms moved across western Wisconsin during the afternoon and evening of July 18th. Most of these storms remain below severe limits, but a couple of storms briefly produced strong enough winds to blow down trees near Fountain City (Buffalo County) and Wonewoc (Juneau County).
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 La Crosse, WI wrote its last area forecast discussion before the first event at Jul 18, 1:18 PM CST, 4 hours 37 minutes earlier.
Area Forecast Discussion National Weather Service La Crosse WI 218 PM CDT Tue Jul 18 2017 .SHORT TERM...(This Evening through Wednesday Night) Issued at 218 PM CDT Tue Jul 18 2017 High Impact Weather Potential: Several bouts of thunderstorms remain possible from this evening through mainly Wednesday night. Can't rule out an isolated severe storm into this evening, though the greater risk for severe could come toward Wednesday night with increasing signals for a potential wind-producing MCS crossing the region. Today's attempt at a convective forecast is brought to you by the words "uncertainty" and "good luck". As discussed at length for the past few days, forecast confidence regarding any one convective solution the next few days (into Saturday really) is quite low, owing to lots of questions regarding the placement of best instability as well as a wavering frontal boundary which will serve as a focus for convective activity. Some good news at least - today's forecast so far is behaving somewhat as expected, with an earlier convectively-enhanced vort lifting from south-central Minnesota into northwest Minnesota, as a trailing "cold" front continues to advance southward toward the area, itself driven by a ridge-running shortwave over northern Minnesota. After earlier activity just skirted our western areas, starting to see some convective elements develop on the southern flank of that shortwave, with additional scattered convection expected to expand along the front as it lays out across the area. Mixed layer CAPE isn't anything great - generally about 1300 J/kg give or take - and both low level and deep layer shear aren't terribly impressive either (maybe 20 knots). As such, continue to believe we're mostly looking at a pulse-type environment, with a lower end risk for a rogue severe storm producing mainly wind and perhaps some smaller hail (pretty warm aloft for anything too large). Things still look to quiet down tonight into Wednesday as the frontal boundary likely gets pushed down into at least northern if not central or southern Iowa (the more widespread the storms today, the farther south it should be). Can't rule out something bubbling up overnight as our airmass remains rather moist, though overall forcing is quite weak. Maybe we could sneak something into northern Iowa on the edge of the strongest capping building north from the central Plains, though again confidence isn't too great. Of greater confidence is Wednesday being a mainly dry day with bubble high development across the region and likely an influx of lower dew points for many areas. Focus then shifts back into north/south Dakota late in the day with persistent hints of another shortwave working through that area, and encountering a quite unstable airmass. Given the pattern with a large heat dome just to our south (well capped off of course) and expanding instability northward with time coupled with an uptick in modest mid level flow, really wondering if we may see a much more organized MCS roll east out of North Dakota during the afternoon. Should that occur, Corfidi vector propagation would suggest a gradual southward turn into our direction in between the capped environment to the south and nil instability to the north. This bears watching if storms can get organized for a potential damaging wind risk. .LONG TERM...(Thursday through Tuesday) Issued at 218 PM CDT Tue Jul 18 2017 Unfortunately, forecast confidence only continues to decline into late week and Saturday (maybe Sunday too?) with lots of questions regarding the position of our focusing frontal boundary. Still like the idea of a mainly dry day on Thursday as we again see bubble high development over the region. Thereafter, there remains a pretty good signal for another round of convection across the area sometime on Friday, though timing/placement concerns remain, with another bout possible toward Saturday with guidance hints of a stronger wave sliding by just to the north. While overall confidence on the specifics is low, the risk for repeated rounds of heavier rain is certainly there, though we'll have to see how our first two rounds of storms unfold through Wednesday night. One bit of good news perhaps is that much of Sunday and into early next week continue to look on the much quieter and potentially cooler side as low level Canadian ridging expands across the region. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1157 AM CDT Tue Jul 18 2017 A cold front will drop southward through the area this afternoon into tonight. Scattered showers and storms are expected along/ahead of the front as it moves through. Looks like shra/ts should be in the vicinity of the KRST/KLSE sites by 21Z with tempo TS likely through 02-03z. Looking like we should maintain mainly VFR conditions with tempo reduction into MVFR in TS activity. Drier/northerly flow behind the cold front should inhibit fog formation but will maintain a close watch on this at KLSE in the Mississippi River valley where wind flow will be lighter. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && SHORT TERM...Lawrence LONG TERM...Lawrence AVIATION...DAS
Hazardous Weather Outlook National Weather Service La Crosse WI 450 AM CDT Tue Jul 18 2017 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029- 032>034-041>044-053>055-061-191200- Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette- Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston- Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau- Adams-Vernon-Crawford-Richland-Grant- 450 AM CDT Tue Jul 18 2017 This Hazardous Weather Outlook is for portions of southeast Minnesota...northeast Iowa and southwest into central Wisconsin. .DAY ONE...Today and Tonight Heat indices this afternoon are expected to reach 95 to 100 across central and southwest Wisconsin, northeast Iowa, and parts of southeast Minnesota. Thunderstorms are likely from mid afternoon through this evening. Some storms may produce locally heavy rainfall, with isolated damaging wind gusts and large hail also possible. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Thunderstorms are likely Wednesday night with locally heavy rainfall and damaging winds possible. Periodic thunderstorm chances will continue Thursday through Saturday night. While it is too early to discern any potential severe threats during this time, locally heavy rainfall is possible. Localized flooding is possible in any areas impacted by repeated thunderstorms with heavy rainfall through late this week. .SPOTTER INFORMATION STATEMENT... Spotter activation may be requested this afternoon and evening. .EMERGENCY MANAGEMENT COORDINATION... No webinar is scheduled. JAM
Special Weather Statement National Weather Service La Crosse WI 154 PM CDT Tue Jul 18 2017 IAZ008-009-018-MNZ079-086>088-094>096-WIZ017-029-032>034-041>044- 182200- Mitchell-Howard-Floyd-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore- Houston-Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe- Juneau-Adams- Including the cities of Osage, Cresco, Charles City, Wabasha, Dodge Center, Rochester, Winona, Austin, Preston, Caledonia, Medford, Neillsville, Alma, Arcadia, Whitehall, Black River Falls, La Crosse, Sparta, Tomah, Mauston, and Friendship 154 PM CDT Tue Jul 18 2017 ...Storms Quickly Developing... Thunderstorms were quickly developing across the area, and scattered storms can be expected to persist through the rest of the afternoon hours. The strongest storms will produce heavy rainfall, and be capable of 1/2 hail.
Special Weather Statement National Weather Service La Crosse WI 358 PM CDT Tue Jul 18 2017 IAZ008>011-018-019-MNZ088-094>096-WIZ033-034-041>044-053-182300- Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Winona-Mower- Fillmore-Houston-Trempealeau-Jackson-La Crosse-Monroe-Juneau- Adams-Vernon- Including the cities of Osage, Cresco, Decorah, Waukon, Charles City, New Hampton, Winona, Austin, Preston, Caledonia, Arcadia, Whitehall, Black River Falls, La Crosse, Sparta, Tomah, Mauston, Friendship, and Viroqua 358 PM CDT Tue Jul 18 2017 ...Scattered Storms Into Early Evening... At late afternoon, thunderstorms continue to develop along a cold front that ran roughly along the Interstate 90 corridor. The storms were moving east, while the front was slowly sinking south. Storms will continue to spark around the boundary into the early evening. The strongest storms will produce heavy rainfall, and be capable of 1/2 hail with wind gusts to 30 mph.
Special Weather Statement National Weather Service La Crosse WI 404 PM CDT Tue Jul 18 2017 IAZ008-009-018-019-182330- Mitchell-Howard-Floyd-Chickasaw- Including the cities of Osage, Cresco, Charles City, and New Hampton 404 PM CDT Tue Jul 18 2017 ...Conditions Favorable for Funnel Clouds... A line of thunderstorms will move into Mitchell and Floyd Counties through 5 pm, and into Howard and Chickasaw Counties through 6 pm. Several reports of funnel clouds have been received over Worth and Cerro Gordo Counties from these storms, and additional funnels are possible into early evening. These funnels typically do not reach the ground. However remain alert as storms arrive and move to a place of safety should a funnel approach the ground. Lawrence
Special Weather Statement National Weather Service La Crosse WI 515 PM CDT Tue Jul 18 2017 MNZ094-095-182330- Mower-Fillmore- Including the cities of Austin and Preston 515 PM CDT Tue Jul 18 2017 ...Funnel clouds possible through 7 PM... Atmospheric conditions are favorable for the formation of short lived funnels through 7 PM. These funnel clouds normally do not touch the ground. As a result, they rarely do any damage and last only a few minutes. Remain on the alert and be prepared to move to a place of safety if a funnel should approach the ground. Wetenkamp
Special Weather Statement National Weather Service La Crosse WI 616 PM CDT TUE JUL 18 2017 WIZ044-182330- Adams- 616 PM CDT TUE JUL 18 2017 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN ADAMS COUNTY... At 615 PM CDT, a strong thunderstorm was located 9 miles north of Wisconsin Dells, moving east at 20 mph. Winds in excess of 30 mph and half inch hail are possible with this storm. This storm will remain over mainly rural areas of southeastern Adams County, including the following locations: Brooks, K And L Campground, Coons Deep Lake Campground, Highway 82 And County B and Big Spring. LAT...LON 4374 8977 4384 8969 4383 8960 4365 8960 TIME...MOT...LOC 2315Z 289DEG 18KT 4375 8971 Hollan
Special Weather Statement
National Weather Service La Crosse WI
632 PM CDT TUE JUL 18 2017
MNZ088-190000-
Winona-
632 PM CDT TUE JUL 18 2017
...A STRONG THUNDERSTORM WILL AFFECT NORTHERN WINONA COUNTY...
At 632 PM CDT, a strong thunderstorm was located near Lewiston, or 10
miles west of Winona, moving east at 55 mph.
Winds in excess of 30 mph and nickel size hail are possible with this
storm.
This storm will be near...
Winona, Goodview and Fountain City around 640 PM CDT.
Trempealeau around 655 PM CDT.
Other locations impacted by this storm include Utica, Minnesota City,
Whitman, County Roads 28 And 31 and Pickwick.
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 4416 9180 4413 9175 4413 9173 4412 9171
4410 9171 4410 9168 4407 9166 4405 9161
4403 9159 4402 9151 4401 9149 4401 9146
4400 9143 4393 9194 4411 9200
TIME...MOT...LOC 2332Z 255DEG 49KT 4404 9186
WetenkampThe La Crosse radar (KARX), 56 km away, was scanning. The volume nearest the first event began at 23:55 UTC.
2 thunderstorm wind. Local standard time, as filed.
Trees were blown down near Fountain City with one of these landing across a road.
Numerous trees were blown down in the Township of Wonewoc.
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, July 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: 708597, 708598.