The Storm Prediction Center’s Day 1 outlook on September 11 placed a Slight Risk across the Upper Midwest, citing modest instability, 40-45 kt deep-layer shear, and strengthening low-level jet support for supercells capable of large hail and a couple of tornadoes, primarily late afternoon into evening. Cities and counties highlighted included Watertown and Aberdeen, South Dakota, plus Willmar, St. Cloud, Brainerd, Hibbing, and Duluth, Minnesota, where effective SRH values were forecast to reach 250-300 m²/s². No higher categorical risks or confirmed tornado reports emerged from official sources that day, keeping market-implied odds aligned with the limited, conditional threat rather than widespread activity. Updated model guidance and any local storm surveys released September 12 could further refine resolution criteria.
Experimentelle KI-generierte Zusammenfassung mit Polymarket-Daten. Dies ist keine Handelsberatung und spielt keine Rolle bei der Auflösung dieses Marktes. · AktualisiertWelche Städte sind am 11. September einem Tornado-Risiko ausgesetzt?
$4,929 Vol.
Chicago, IL
Nein
Houston, TX
Nein
San Antonio, TX
Nein
Dallas, TX
Nein
Austin, TX
Nein
Fort Worth, TX
Nein
Columbus, OH
Nein
Charlotte, NC
Nein
Indianapolis, IN
Nein
Denver, CO
Nein
Nashville, TN
Nein
Oklahoma City, OK
Nein
Memphis, TN
Nein
Louisville, KY
Nein
Atlanta, GA
Nein
Kansas City, MO
Nein
Omaha, NE
Nein
Minneapolis, MN
Nein
Wichita, KS
Nein
New Orleans, LA
Nein
Tampa, FL
Nein
St. Louis, MO
Nein
Birmingham, AL
Nein
Des Moines, IA
Nein
Little Rock, AR
Nein
$4,929 Vol.
Chicago, IL
Nein
Houston, TX
Nein
San Antonio, TX
Nein
Dallas, TX
Nein
Austin, TX
Nein
Fort Worth, TX
Nein
Columbus, OH
Nein
Charlotte, NC
Nein
Indianapolis, IN
Nein
Denver, CO
Nein
Nashville, TN
Nein
Oklahoma City, OK
Nein
Memphis, TN
Nein
Louisville, KY
Nein
Atlanta, GA
Nein
Kansas City, MO
Nein
Omaha, NE
Nein
Minneapolis, MN
Nein
Wichita, KS
Nein
New Orleans, LA
Nein
Tampa, FL
Nein
St. Louis, MO
Nein
Birmingham, AL
Nein
Des Moines, IA
Nein
Little Rock, AR
Nein
The SPC Day 1 Convective Outlook assigns tornado probability percentages (2%, 5%, 10%, etc.) to geographic areas across the US. If the city's coordinates fall inside any area rated 2% or higher, that city resolves "Yes". If a city is outside all tornado probability areas, or only within areas rated below 2%, that city resolves "No".
The SPC outlook is published as machine-readable geographic data (GeoJSON) at spc.noaa.gov. Each city's coordinates and the polygon boundaries are publicly verifiable. Borderline cases can be independently confirmed using the polygon data (excluding the hatched SIGN overlay, which is not a probability rating) and the city's listed coordinates. The point-in-polygon test is performed on unprojected WGS84 (EPSG:4326) coordinates, which is the native coordinate system of the SPC GeoJSON data.
Resolution is based on the scheduled 01:00 UTC Day 1 Convective Outlook update issued on the following UTC calendar day. The SPC Day 1 outlook covers a 24-hour period from 12:00 UTC to 12:00 UTC the following day. Subsequent revisions published after that scheduled update will not be considered. If the SPC Day 1 Convective Outlook has not been published by the time the market closes, this market will resolve to "No".
The resolution source for this market is the NOAA Storm Prediction Center at spc.noaa.gov.
This market uses coordinates 41.8781, -87.6298 for Chicago, IL.
Markt eröffnet: Sep 11, 2026, 8:13 AM ET
Abwicklungsquelle
https://www.spc.noaa.gov/products/outlook/day1otlk.htmlAbwickler
0x65070BE91...Vorgeschlagenes Ergebnis: Nein
Kein Einspruch
Endgültiges Ergebnis: Nein
The SPC Day 1 Convective Outlook assigns tornado probability percentages (2%, 5%, 10%, etc.) to geographic areas across the US. If the city's coordinates fall inside any area rated 2% or higher, that city resolves "Yes". If a city is outside all tornado probability areas, or only within areas rated below 2%, that city resolves "No".
The SPC outlook is published as machine-readable geographic data (GeoJSON) at spc.noaa.gov. Each city's coordinates and the polygon boundaries are publicly verifiable. Borderline cases can be independently confirmed using the polygon data (excluding the hatched SIGN overlay, which is not a probability rating) and the city's listed coordinates. The point-in-polygon test is performed on unprojected WGS84 (EPSG:4326) coordinates, which is the native coordinate system of the SPC GeoJSON data.
Resolution is based on the scheduled 01:00 UTC Day 1 Convective Outlook update issued on the following UTC calendar day. The SPC Day 1 outlook covers a 24-hour period from 12:00 UTC to 12:00 UTC the following day. Subsequent revisions published after that scheduled update will not be considered. If the SPC Day 1 Convective Outlook has not been published by the time the market closes, this market will resolve to "No".
The resolution source for this market is the NOAA Storm Prediction Center at spc.noaa.gov.
This market uses coordinates 41.8781, -87.6298 for Chicago, IL.
Abwicklungsquelle
https://www.spc.noaa.gov/products/outlook/day1otlk.htmlAbwickler
0x65070BE91...Vorgeschlagenes Ergebnis: Nein
Kein Einspruch
Endgültiges Ergebnis: Nein
The Storm Prediction Center’s Day 1 outlook on September 11 placed a Slight Risk across the Upper Midwest, citing modest instability, 40-45 kt deep-layer shear, and strengthening low-level jet support for supercells capable of large hail and a couple of tornadoes, primarily late afternoon into evening. Cities and counties highlighted included Watertown and Aberdeen, South Dakota, plus Willmar, St. Cloud, Brainerd, Hibbing, and Duluth, Minnesota, where effective SRH values were forecast to reach 250-300 m²/s². No higher categorical risks or confirmed tornado reports emerged from official sources that day, keeping market-implied odds aligned with the limited, conditional threat rather than widespread activity. Updated model guidance and any local storm surveys released September 12 could further refine resolution criteria.
Experimentelle KI-generierte Zusammenfassung mit Polymarket-Daten. Dies ist keine Handelsberatung und spielt keine Rolle bei der Auflösung dieses Marktes. · Aktualisiert


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