The National Weather Service Storm Prediction Center’s latest Day 1 Convective Outlook places an Enhanced Risk of severe thunderstorms across eastern Ohio and western Pennsylvania, with a Slight Risk extending through the southern Great Lakes, Upper Midwest, and Mid-Atlantic through tonight. Primary hazards remain damaging winds and large hail, though mixed convective modes including supercells support a conditional tornado threat, reflected in 5% tornado probabilities where deep-layer shear and instability align. Recent model runs and surface observations highlight a frontal boundary and moisture plume favoring organized clusters, consistent with observed tornado warnings in parts of Michigan. Traders monitoring real-time SPC updates, radar trends, and any mesoscale discussions will watch for shifts in shear or instability that could elevate localized tornado probabilities before the valid period ends at 12Z September 4.
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 3?
Chicago, IL
2%
Houston, TX
2%
San Antonio, TX
1%
Dallas, TX
1%
Austin, TX
1%
Fort Worth, TX
1%
Columbus, OH
1%
Charlotte, NC
1%
Indianapolis, IN
1%
Denver, CO
2%
Nashville, TN
1%
Oklahoma City, OK
1%
Memphis, TN
1%
Louisville, KY
2%
Atlanta, GA
2%
Kansas City, MO
1%
Omaha, NE
2%
Minneapolis, MN
1%
Wichita, KS
1%
New Orleans, LA
1%
Tampa, FL
1%
St. Louis, MO
1%
Birmingham, AL
1%
Des Moines, IA
1%
Little Rock, AR
2%
$717 Vol.
Chicago, IL
2%
Houston, TX
2%
San Antonio, TX
1%
Dallas, TX
1%
Austin, TX
1%
Fort Worth, TX
1%
Columbus, OH
1%
Charlotte, NC
1%
Indianapolis, IN
1%
Denver, CO
2%
Nashville, TN
1%
Oklahoma City, OK
1%
Memphis, TN
1%
Louisville, KY
2%
Atlanta, GA
2%
Kansas City, MO
1%
Omaha, NE
2%
Minneapolis, MN
1%
Wichita, KS
1%
New Orleans, LA
1%
Tampa, FL
1%
St. Louis, MO
1%
Birmingham, AL
1%
Des Moines, IA
1%
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 outlook is not published or is unavailable, the market remains open until data is available.
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 3, 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 outlook is not published or is unavailable, the market remains open until data is available.
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 National Weather Service Storm Prediction Center’s latest Day 1 Convective Outlook places an Enhanced Risk of severe thunderstorms across eastern Ohio and western Pennsylvania, with a Slight Risk extending through the southern Great Lakes, Upper Midwest, and Mid-Atlantic through tonight. Primary hazards remain damaging winds and large hail, though mixed convective modes including supercells support a conditional tornado threat, reflected in 5% tornado probabilities where deep-layer shear and instability align. Recent model runs and surface observations highlight a frontal boundary and moisture plume favoring organized clusters, consistent with observed tornado warnings in parts of Michigan. Traders monitoring real-time SPC updates, radar trends, and any mesoscale discussions will watch for shifts in shear or instability that could elevate localized tornado probabilities before the valid period ends at 12Z September 4.
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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