The latest Storm Prediction Center Day 1 convective outlook through early September 11 places no tornado risk areas across the contiguous United States, reflecting limited low-level shear and storm-relative helicity despite a marginal severe thunderstorm area from the southern High Plains into the southern Mid-Atlantic. A shortwave trough and advancing cold front are generating scattered thunderstorms with primary threats of damaging winds and isolated large hail, particularly where moderate instability (MLCAPE 1000-1500 J/kg) overlaps steeper lapse rates in the High Plains and Ohio Valley. Model consensus and current observations indicate insufficient organization for supercells capable of tornadoes on this date, though traders should monitor afternoon updates from the SPC and NWS for any rapid changes in shear profiles or boundary interactions.
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 10?
Chicago, IL
2%
Houston, TX
3%
San Antonio, TX
3%
Dallas, TX
3%
Austin, TX
3%
Fort Worth, TX
2%
Columbus, OH
3%
Charlotte, NC
3%
Indianapolis, IN
3%
Denver, CO
3%
Nashville, TN
3%
Oklahoma City, OK
3%
Memphis, TN
3%
Louisville, KY
3%
Atlanta, GA
2%
Kansas City, MO
2%
Omaha, NE
2%
Minneapolis, MN
2%
Wichita, KS
2%
New Orleans, LA
2%
Tampa, FL
2%
St. Louis, MO
2%
Birmingham, AL
3%
Des Moines, IA
3%
Little Rock, AR
2%
$1,538 Vol.
Chicago, IL
2%
Houston, TX
3%
San Antonio, TX
3%
Dallas, TX
3%
Austin, TX
3%
Fort Worth, TX
2%
Columbus, OH
3%
Charlotte, NC
3%
Indianapolis, IN
3%
Denver, CO
3%
Nashville, TN
3%
Oklahoma City, OK
3%
Memphis, TN
3%
Louisville, KY
3%
Atlanta, GA
2%
Kansas City, MO
2%
Omaha, NE
2%
Minneapolis, MN
2%
Wichita, KS
2%
New Orleans, LA
2%
Tampa, FL
2%
St. Louis, MO
2%
Birmingham, AL
3%
Des Moines, IA
3%
Little Rock, AR
2%
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 10, 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 latest Storm Prediction Center Day 1 convective outlook through early September 11 places no tornado risk areas across the contiguous United States, reflecting limited low-level shear and storm-relative helicity despite a marginal severe thunderstorm area from the southern High Plains into the southern Mid-Atlantic. A shortwave trough and advancing cold front are generating scattered thunderstorms with primary threats of damaging winds and isolated large hail, particularly where moderate instability (MLCAPE 1000-1500 J/kg) overlaps steeper lapse rates in the High Plains and Ohio Valley. Model consensus and current observations indicate insufficient organization for supercells capable of tornadoes on this date, though traders should monitor afternoon updates from the SPC and NWS for any rapid changes in shear profiles or boundary interactions.
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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