The Storm Prediction Center’s latest Day 1 convective outlook places a 2% tornado probability across parts of central North Dakota and southeast South Dakota, driven by a fast-moving shortwave trough interacting with a sharpening dryline and pre-frontal boundary. Modest MLCAPE of 1500–2500 J/kg, 40–45 kt effective bulk shear, and 200–300 m²/s² SRH favor supercell development this afternoon and evening, with large hail as the primary threat and an isolated tornado or two possible where low-level veering is strongest. Cities such as Minot, Bismarck, Mitchell, and Huron lie within or near the risk area. Updated SPC outlooks and real-time mesoscale observations will refine the exact corridors before the period ends at 12Z September 8.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedWhich cities face tornado risk on September 7?
Chicago, IL
4%
Houston, TX
4%
San Antonio, TX
3%
Dallas, TX
4%
Austin, TX
3%
Fort Worth, TX
50%
Columbus, OH
1%
Charlotte, NC
3%
Indianapolis, IN
3%
Denver, CO
3%
Nashville, TN
3%
Oklahoma City, OK
3%
Memphis, TN
1%
Louisville, KY
4%
Atlanta, GA
3%
Kansas City, MO
3%
Omaha, NE
3%
Minneapolis, MN
50%
Wichita, KS
4%
New Orleans, LA
50%
Tampa, FL
3%
St. Louis, MO
3%
Birmingham, AL
3%
Des Moines, IA
3%
Little Rock, AR
3%
$1,216 Vol.
Chicago, IL
4%
Houston, TX
4%
San Antonio, TX
3%
Dallas, TX
4%
Austin, TX
3%
Fort Worth, TX
50%
Columbus, OH
1%
Charlotte, NC
3%
Indianapolis, IN
3%
Denver, CO
3%
Nashville, TN
3%
Oklahoma City, OK
3%
Memphis, TN
1%
Louisville, KY
4%
Atlanta, GA
3%
Kansas City, MO
3%
Omaha, NE
3%
Minneapolis, MN
50%
Wichita, KS
4%
New Orleans, LA
50%
Tampa, FL
3%
St. Louis, MO
3%
Birmingham, AL
3%
Des Moines, IA
3%
Little Rock, AR
3%
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.
Market Opened: Sep 7, 2026, 8:13 AM ET
Resolution Source
https://www.spc.noaa.gov/products/outlook/day1otlk.htmlResolver
0x65070BE91...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.
Resolution Source
https://www.spc.noaa.gov/products/outlook/day1otlk.htmlResolver
0x65070BE91...The Storm Prediction Center’s latest Day 1 convective outlook places a 2% tornado probability across parts of central North Dakota and southeast South Dakota, driven by a fast-moving shortwave trough interacting with a sharpening dryline and pre-frontal boundary. Modest MLCAPE of 1500–2500 J/kg, 40–45 kt effective bulk shear, and 200–300 m²/s² SRH favor supercell development this afternoon and evening, with large hail as the primary threat and an isolated tornado or two possible where low-level veering is strongest. Cities such as Minot, Bismarck, Mitchell, and Huron lie within or near the risk area. Updated SPC outlooks and real-time mesoscale observations will refine the exact corridors before the period ends at 12Z September 8.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated

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