A couple thunderstorms developed during the evening of August 03 across east central Minnesota. One thunderstorm produced a microburst that caused damage to a pontoon boat and dock.
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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 MPX wrote it up.
A couple thunderstorms developed during the evening of August 03 across east central Minnesota. One thunderstorm produced a microburst that caused damage to a pontoon boat and dock. There were no other reports of 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 Twin Cities, MN wrote its last area forecast discussion before the first event at Aug 3, 1:00 PM CST, 3 hours 53 minutes earlier.
Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 200 PM CDT Thu Aug 3 2023 .DISCUSSION...(This evening through Thursday) Issued at 148 PM CDT Thu Aug 3 2023 KEY MESSAGES: - The chance for widespread rainfall this weekend remains, but details have yet to be fully ironed out. Saturday night into early Sunday currently looks to be the day with the best chance for a longer duration rain event for most locations. Isolated SHRA have been seen in the southern portion of the area this afternoon, and a few more are certainly possible near the diffuse frontal boundary as it slowly sags south. There is plenty of instability, but very little shear, so the main impact would be locally heavy rainfall like yesterday afternoon/evening (although activity appears it will be even more limited today given weaker low-level convergence). Drier air will work into the area tonight and Friday, with cooler and less humid conditions on Friday (although highs will still be in the upper 80s). After that attention turns toward the weekend, when there still appears to be a good chance for most of the area to see at least a quarter to half inch of rainfall. The numerical guidance is in reasonable agreement on the large scale features for Friday night through Sunday night, but there are widely varying opinions with respect to the details. The upper wave that will move east from the central and northern Rockies will be impacted by upstream convection over the high Plains, which will have substantial downstream implications with respect to where and when the most widespread and heaviest SHRA/TSRA occurs over the upper Midwest. The NAM is the most aggressive in developing northern upstream convection, and the feedback from that brings a swath of heavy precipitation through our area. The GFS on the other hand is not as concentrated with upstream activity and doesn't modify the upper level PV anomaly to the same extent as the NAM, and is quite dry for much of our area, focusing heavier precipitation mainly to our south. The ECMWF is more similar to the NAM, but not quite as amplified with things, and its accompanying EPS solutions generally favor the deterministic solution (albeit with an expected amount of spread in location/amounts). Needless to say, specific amounts and timing of precipitation remains a bit uncertain, but the primary time frame for most of the area looks to be from late Saturday afternoon through Sunday morning (particularly Saturday night), with the best chance for higher amounts looking to be near and south of Interstate 94. Forecast PoPs ramp up Saturday into Saturday night, with likely PoPs over much of the area Saturday night, then taper off later Sunday, with just some lingering chance PoPs in the east on Monday. One thing that is much more certain is the transition toward cooler temperatures, with highs only near 80 on Saturday, in the 70s Sunday, then mainly from around 80 into the lower 80s for the remainder of the period. Some chance PoPs return to the area later Wednesday into Thursday as the next shortwave trough and surface front move through the region (with fairly decent agreement on its position and timing given the forecast time frame). && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 1203 PM CDT Thu Aug 3 2023 The diffuse cold frontal boundary currently over the area will continue to slowly sag south through the period as a ridge of high pressure builds in from the north. Isolated SHRA/TSRA is possible over the southern portion of the area this afternoon where abundant instability (but weak forcing) is present. Coverage and likelihood is too low to include any mention in the forecast, but KRWF and KMKT would be the only locations where anything might occur. Otherwise, VFR conditions and veering light winds are expected through the period. KMSP...No concerns. Any isolated convection this afternoon should be south of the area. Light winds will veer from WNW to E through the period. /OUTLOOK FOR KMSP/ Friday night...VFR. Northeast wind less than 10 kt. Saturday...VFR. Southeast wind 10 kt or less. Saturday night...MVFR possible with a chance of SHRA/TSRA. Variable wind 10 kt or less. Sunday...MVFR possible with a chance of SHRA/TSRA. Northwest wind around 10 kt. Sunday night...VFR. Variable wind 5 kt or less. Monday...VFR. Northwest wind around 5 kt. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && DISCUSSION...WFO MPX AVIATION...WFO MPX
Hazardous Weather Outlook National Weather Service Twin Cities/Chanhassen MN 918 AM CDT Thu Aug 3 2023 MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028- 041430- Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns- Benton-Sherburne-Isanti-Chisago-Lac Qui Parle-Swift-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- 918 AM CDT Thu Aug 3 2023 This Hazardous Weather Outlook is for portions of central and southern Minnesota, and west central Wisconsin. .DAY ONE...Today and Tonight. Hot and humid conditions will bring heat indices into the 90s this afternoon. There will be an elevated risk for heat illness for those who are active outdoors. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. Thunderstorms are expected over the weekend. Heavy rain will be possible, along with isolated severe storms. .SPOTTER INFORMATION STATEMENT... SKYWARN spotter activation will not be needed.
The Minneapolis radar (KMPX), 69 km away, was scanning. The volume nearest the first event began at 22:53 UTC.
1 thunderstorm wind. Local standard time, as filed.
A pontoon was flipped and a dock sunk after very strong south winds and heavy rain moved through the area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2023Every state in 2023This day in weather historyWarnings in Minnesota, August 2023
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: 1139458.