The NOAA Storm Prediction Center's Day 1 convective outlook for August 20, 2026, established the primary driver for trader sentiment by designating a Slight Risk (level 2/5) across the Mid-Atlantic, including the Philadelphia, Baltimore, Washington DC, and Charlotte metros, where atmospheric instability and low-level shear supported a 2-5% tornado probability alongside damaging winds. A separate marginal threat extended into the Upper Midwest near Minneapolis. Official SPC guidance highlighted supercell potential and isolated tornadoes in an unstable airmass, consistent with historical August patterns favoring northern-tier activity due to jet stream positioning. Updated model runs and real-time observations on the day refined these contours, with any post-event verification data or revised outlooks likely influencing final resolution probabilities.
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 August 20?

Chicago, IL
50%

Houston, TX
50%

San Antonio, TX
50%

Dallas, TX
50%

Austin, TX
50%

Fort Worth, TX
50%

Columbus, OH
50%

Charlotte, NC
50%

Indianapolis, IN
50%

Denver, CO
50%

Nashville, TN
50%

Oklahoma City, OK
50%

Memphis, TN
50%

Louisville, KY
50%

Atlanta, GA
50%

Kansas City, MO
50%

Omaha, NE
50%

Minneapolis, MN
50%

Wichita, KS
50%

New Orleans, LA
50%

Tampa, FL
50%

St. Louis, MO
50%

Birmingham, AL
50%

Des Moines, IA
50%

Little Rock, AR
50%
$0.00 Vol.

Chicago, IL
50%

Houston, TX
50%

San Antonio, TX
50%

Dallas, TX
50%

Austin, TX
50%

Fort Worth, TX
50%

Columbus, OH
50%

Charlotte, NC
50%

Indianapolis, IN
50%

Denver, CO
50%

Nashville, TN
50%

Oklahoma City, OK
50%

Memphis, TN
50%

Louisville, KY
50%

Atlanta, GA
50%

Kansas City, MO
50%

Omaha, NE
50%

Minneapolis, MN
50%

Wichita, KS
50%

New Orleans, LA
50%

Tampa, FL
50%

St. Louis, MO
50%

Birmingham, AL
50%

Des Moines, IA
50%

Little Rock, AR
50%
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.
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: Aug 20, 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.
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 NOAA Storm Prediction Center's Day 1 convective outlook for August 20, 2026, established the primary driver for trader sentiment by designating a Slight Risk (level 2/5) across the Mid-Atlantic, including the Philadelphia, Baltimore, Washington DC, and Charlotte metros, where atmospheric instability and low-level shear supported a 2-5% tornado probability alongside damaging winds. A separate marginal threat extended into the Upper Midwest near Minneapolis. Official SPC guidance highlighted supercell potential and isolated tornadoes in an unstable airmass, consistent with historical August patterns favoring northern-tier activity due to jet stream positioning. Updated model runs and real-time observations on the day refined these contours, with any post-event verification data or revised outlooks likely influencing final resolution probabilities.
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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