A line of severe thunderstorms moved across north-central Wisconsin during the late evening hours, producing minor wind 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 GRB wrote it up.
A line of severe thunderstorms moved across north-central Wisconsin during the late evening hours, producing minor wind damage.
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 Green Bay, WI wrote its last area forecast discussion before the first event at Jul 8, 6:16 PM CST, 3 hours 14 minutes earlier.
Area Forecast Discussion National Weather Service Green Bay WI 716 PM CDT Wed Jul 8 2020 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Thursday Issued at 310 PM CDT Wed Jul 8 2020 The MCS that formed over Minnesota last night dissipated as it moved into northcentral Wisconsin this afternoon. It was able to produce wind gusts to 40 mph over northwest Marathon county. Middle and high clouds from that system held temperatures down for part of the day, so it did not get quite as hot as expected in the north. There is a chance of a shower or thunderstorm this afternoon or evening along a lake or bay breeze or outflow boundary, but do not expected much. Another convective system may form across northeast Minnesota or western Upper Michigan later this evening, and move south across Wisconsin late tonight. If it does it may slow the formation of thunderstorms ahead of a cold front late in the day Thursday. CAPE values of 2000 to 3000 J/KG are possible if we have sunny skies. Shear seems sufficient to get some severe storms in the late afternoon and evening. Freezing levels and LCL heights are rather high, so the main threat seems to be strong winds and very heavy rain. Heat indices in the low to mid 90s are likely in most places. .LONG TERM...Thursday Night Through Wednesday Issued at 310 PM CDT Wed Jul 8 2020 The main focus of the long term will be the ongoing thunderstorm potential Thursday night into Friday, the small drop in temperatures over the weekend, and the slow return of heat, humidity, and storms next week Thursday night into Friday...Large scale ascent associated with increasing positive vorticity advection will support convective development in the evening hours of Thursday into Friday night. Any ongoing convection from the afternoon will likely sustain itself into the evening. As diurnally driven instability starts to dissipated, the storms will gradually weaken, but an isolated severe threat remains present. Shear remains weak during this time, so the threat will be mainly limited to heavy rain and high winds. Behind the system, northwesterly flow will bring in some cooler and less humid conditions for Friday and Friday night, with minimal additional rain chances to start the weekend. Rest of the forecast...Summer like convection continues to be in the forecast through the weekend and into next week. Diurnal instability and several weak shortwaves will create additional shower and storm chances for the region throughout the period, much as we had the past week or so. Kept with general guidance for now, as confidence on timing and location remains low. Temperatures and dewpoints will begin to rise next week again, as winds once again shift to the southwest. && .AVIATION...for 00Z TAF Issuance Issued at 714 PM CDT Wed Jul 8 2020 Deep convection associated with an upper-level disturbance and frontal boundary has been steadily developing across central MN ENE to far NW Wisconsin early this evening. Various short-term model guidance is not in very good agreement on how this convection will evolve during the evening and overnight, thus confidence with respect to where and when thunderstorms will impact TAF sites during the current forecast period is low. Best guess is convection will gradually sag southeast and weaken somewhat before it impacts RHI TAF site sometime around 06-08 UTC, then perhaps impact AUW and GRB TAF sites after 08 UTC. Before convection weakens, could be a few surface wind gusts to 30-35 kts with MVFR conditions, primarily impacting RHI and areas north of I29. Convection is expected to weaken toward daybreak with VFR conditions returning briefly, before more widespread thunderstorm activity develops across much of the forecast area during the afternoon, bringing MVFR cigs and vsbys and perhaps a few isolated wind gusts in excess of 35 kts, roughly between about 20 and 24 UTC Thursday. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM.....RDM LONG TERM......Uhlmann AVIATION.......ESB
Hazardous Weather Outlook National Weather Service Green Bay WI 255 PM CDT Wed Jul 8 2020 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-092000- Vilas-Oneida-Forest-Florence-Northern Marinette County-Lincoln- Langlade-Menominee-Northern Oconto County-Door-Marathon-Shawano- Wood-Portage-Waupaca-Outagamie-Brown-Kewaunee-Waushara-Winnebago- Calumet-Manitowoc-Southern Marinette County- Southern Oconto County- 255 PM CDT Wed Jul 8 2020 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Tonight Thunderstorms may form over Upper Michigan this evening and move south across northern and central Wisconsin overnight. There is a marginal risk of severe storms over northcentral Wisconsin. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday Hot and humid weather will continue Thursday with heat indices in the low to mid 90s in most places. There is a slight risk of severe storms on Thursday, especially over central and east central Wisconsin. The strongest storms will be capable of producing damaging winds, torrential rainfall and hail. Be sure to monitor later forecasts for more detailed information. Thunderstorms will be possible at times from Friday through the weekend, but the risk of severe weather looks low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected tonight. LMZ521-522-541>543-092000- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 255 PM CDT Wed Jul 8 2020 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight There is a chance of thunderstorms late tonight. Any storms may pose a risk to boaters. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday Scattered thunderstorms are expected at times from Thursday through the weekend. Any thunderstorms that develop will pose a hazard to boaters on the lake and bay. RDM/Uhlmann
Special Weather Statement National Weather Service Green Bay WI 858 PM CDT Wed Jul 8 2020 WIZ005-010>012-090400- Vilas-Oneida-Forest-Florence- 858 PM CDT Wed Jul 8 2020 ...THUNDERSTORMS APPROACHING NORTH CENTRAL WISCONSIN LATE THIS EVENING... Strong thunderstorms located across northwest Wisconsin at 900 PM will continue to move east towards north central Wisconsin during the next one to two hours. Storms are expected to reach western Vilas County between 10:00 and 10:30 PM. Additional thunderstorms may develop across the Wisconsin and Upper Michigan border. These storms may be capable of producing damaging wind gusts, heavy rainfall, penny sized hail, and frequent cloud to ground lightning. Have a way to receive warning messages should one be issued for your location. KLJ
The Marquette radar (KMQT), 170 km away, was scanning. The volume nearest the first event began at 03:29 UTC.
3 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds downed trees in Presque Isle. The time of this report is an estimate based on radar data.
Thunderstorm winds downed trees in Lac du Flambeau. The time of this report is an estimate based on radar data.
Thunderstorm winds downed trees in Minocqua. The time of this report is an estimate based on radar data.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2020Every state in 2020This day in weather historyWarnings in Wisconsin, July 2020
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: 897374, 897381, 897399.