A thunderstorm developed across southeast Minnesota during the afternoon of Tuesday, July 6th. This storm intensified as it moved across the Mississippi River and northeast toward Eau Claire County of west central Wisconsin.
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 MPX wrote it up.
A thunderstorm developed across southeast Minnesota during the afternoon of Tuesday, July 6th. This storm intensified as it moved across the Mississippi River and northeast toward Eau Claire County of west central Wisconsin. This storm bowed out as it moved into southern Eau Claire County where trees were blown down near the Trempealeau and Eau Claire border. Other trees were blown down as it moved across southern Eau Claire County before moving off to the east.
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 Twin Cities, MN wrote its last area forecast discussion before the first event at Jul 6, 1:27 PM CST, 17 minutes earlier.
Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 227 PM CDT Tue Jul 6 2021 .SHORT TERM...(This evening through Wednesday night) Issued at 227 PM CDT Tue Jul 6 2021 Areas of showers and thunderstorms are present across our CWA this afternoon and will continue with a chance for some stronger storms by the late afternoon to early evening, mainly in southern MN. The strongest storms will remain south of the Twin Cities, with the better storm environment and dynamics expected to remain along the cold front stretching from the low pressure system over the area. MLCAPE of around 1000-2000 J/KG is present within southern MN and western WI, combining with dynamics associated with an MCV propagating along with the low to give us our potential for severe weather. Right now, the biggest overall risk looks to be strong wind gusts to 60-70mph along any bowing segments in the line of storms along the front, however some large hail up to 1-1.5 inches is possible should any lone supercells develop, and a tornado or two is also possible but mainly along the southern portions of the line in parts of Iowa and far southern MN. The last main point of concern is plenty of moisture to work with, with PWAT values of 1.5 to 1.7 inches, which will allow for some locally heavy downpours which could end up enhancing any strong wind gusts as well. Areas north of the center of the Low pressure system, namely from the Twin Cities and farther north, will likely end up seeing just generic rain showers with a few bouts of thunder and lightning, but no major severe weather as the cold front and MCV south of the low remains the primary driver of the severe potential. Temperatures have been struggling to rise today due to the showers and cloud cover, with areas of southern MN finally hitting 80 over the last hour or so as most of us sit in the mid to upper 70s. With showers expected to linger on into the evening before falling back overnight as the cold front departs, temperatures will gradually fall as well with overnight lows in the mid to upper 50s. A bit of fog is possible tomorrow morning lingering into midday due to a lack of wind and the moisture present from the showers today, which will keep temperatures in the upper 60s to low 70s with clearing skies tomorrow afternoon. Our next chance for rain looks to take place on Friday, be sure to read the long term discussion for further details! .LONG TERM...(Thursday through Tuesday) Issued at 227 PM CDT Tue Jul 6 2021 Expect a cool and wet start to this period with a gradual warming trend. Continued potential for heavy rain and thunderstorms on Friday. Thursday into Sunday... Continuing to track a shortwave that will move into the Upper Midwest from OR/WA later this week brining us our next chance for rain and thunderstorms. The southerly shift mentioned in the previous discussion has held with the best chances for rain along and south of the I-94 corridor on Friday. There continues to be differences though between different deterministic systems such as the GFS and ECMWF on how this wave evolve into the weekend. The GFS moves this wave out much faster, while in the ECMWF it lingers in the Midwest longer. We continue to see a wide variety of QPF among ensemble members across southern Minnesota where the forcing will be best for both rainfall and thunderstorm chances. As far as deep convection is concerned shear continues to look good in much of the model guidance, but instability remains the question. Instability varies much between both deterministic models and the various ensembles members. Bottom line widespread rainfall still looks likely, but farther south with heavy rain and thunderstorms possible (most likely in southern Minnesota). On the temperature front cooler temperatures will continue, but gradually warm up to near normal by the end of the weekend. Next week... As the previous week's system moves off to the east high pressure and warmer air will settle in early next week. This will result in normal temperatures to slightly above normal temperatures depending on how the 850 mb winds set up. There should be an early week break from rain chances with a slight ridge aloft ahead of the next trough. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1238 PM CDT Tue Jul 6 2021 A tricky TAF period as ongoing showers north of a low pressure system will continue to be present for many sites, with a chance for TSRA along our southern sites by around 20-22Z. VIS and CIG drops to MVFR and IFR in spots as rain continues, with CIGS dropping even further overnight as the rain wraps up, to be replaced by potential for fog lingering into the end of the period. Winds could gust briefly due to showers and any storms, but generally remain fairly weak at 5-10kts out of the NE. A few amendments are possible depending on where the thunderstorms set up, generally expected for RWF, MKT, MSP, and EAU.\ KMSP...It is still a question on whether or not storms will end up near MSP from about 21-00Z, with short range CAM guidance going back and forth on how far north thunderstorms end up. Right now, storms are expected to remain far enough south of the terminal where they should not be an issue. After the system moves on by 06-12Z tomorrow morning, the main issue becomes how widespread and thick any potential fog might be, which was omitted from the TAF for now due to being end of period and low confidence. /OUTLOOK FOR KMSP/ WED...MVFR early, otherwise VFR. Wind NE 5-10kts. THU...VFR. Wind VRB bcmg SE 5-10kts. FRI...MVFR/SHRA likely, chc -TSRA. Wind SE 10-15kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && SHORT TERM...TDH LONG TERM...NDC AVIATION...TDH
Hazardous Weather Outlook National Weather Service Twin Cities/Chanhassen MN 1144 AM CDT Tue Jul 6 2021 MNZ053-054-056>070-073>078-082>085-091>093-WIZ014>016-023>028- 071645- Chisago-Lac Qui Parle-Chippewa-Kandiyohi-Meeker-Wright-Hennepin- Anoka-Ramsey-Washington-Yellow Medicine-Renville-McLeod-Sibley- Carver-Scott-Dakota-Redwood-Brown-Nicollet-Le Sueur-Rice-Goodhue- Watonwan-Blue Earth-Waseca-Steele-Martin-Faribault-Freeborn-Polk- Barron-Rusk-St. Croix-Pierce-Dunn-Pepin-Eau Claire- 1144 AM CDT Tue Jul 6 2021 This Hazardous Weather Outlook is for portions of central and southern Minnesota, and west central Wisconsin. .DAY ONE...This Afternoon and Tonight. Thunderstorms are likely today and tonight, with a slight risk of severe storms. The main threat will be damaging winds with a chance for some large hail and isolated tornados. Locally heavy rainfall is also likely, especially within thunderstorms. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Thunderstorms are possible again Friday with some stronger storms capable of gusty winds, hail, and heavy rainfall. .SPOTTER INFORMATION STATEMENT... SKYWARN spotter activation may be needed. MNZ041>045-047>052-055-071645- Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns- Benton-Sherburne-Isanti-Swift- 1144 AM CDT Tue Jul 6 2021 This Hazardous Weather Outlook is for portions of central Minnesota...east central Minnesota and west central Minnesota. .DAY ONE...This Afternoon and Tonight. Rain showers today with a chance for some isolated thunderstorms and locally heavy rain. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Thunderstorms are possible again Friday with some stronger storms capable of gusty winds, hail, and heavy rainfall. .SPOTTER INFORMATION STATEMENT... SKYWARN spotter activation is not expected.
The La Crosse radar (KARX), 90 km away, was scanning. The volume nearest the first event began at 19:43 UTC.
2 thunderstorm wind. Local standard time, as filed.
An 18 inch diameter tree was blown down southwest of Allen.
Several large trees were blown down along Highway 53, south of Foster.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2021Every state in 2021This day in weather historyWarnings in Wisconsin, July 2021
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: 958268, 958269.