- Will Chicago, IL face tornado risk on September 1?0¢
- Will Houston, TX face tornado risk on September 1?0¢
- Will San Antonio, TX face tornado risk on September 1?0¢
- Will Dallas, TX face tornado risk on September 1?0¢
- Will Austin, TX face tornado risk on September 1?0¢
- Will Fort Worth, TX face tornado risk on September 1?0¢
- Will Columbus, OH face tornado risk on September 1?0¢
- Will Charlotte, NC face tornado risk on September 1?0¢
- Will Indianapolis, IN face tornado risk on September 1?0¢
- Will Denver, CO face tornado risk on September 1?0¢
- Will Nashville, TN face tornado risk on September 1?0¢
- Will Oklahoma City, OK face tornado risk on September 1?0¢
This market will resolve to "Yes" for each listed city that falls within a tornado probability area rated ≥2% in the NOAA Storm Prediction Center Day 1 Convective Outlook on September 1, 2026. Otherwise, this market will resolve to "No". The SPC Day 1 Convective Outlook assigns tornado probability percentages (2%, 5%, 10%, etc.) to geographic areas across the US. If a 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.
The Storm Prediction Center’s Day 1 convective outlooks for September 1, 2026, placed a Slight risk of severe thunderstorms across the Northeast and Mid-Atlantic, citing 2% tornado probabilities tied to moderate CAPE, 35–45 kt effective shear, and strengthening low-level winds near a surface front. New York, Philadelphia, and surrounding population centers fell within the highest-probability corridor, while a separate marginal-to-slight area extended into the northern/central Plains and Upper Midwest, where discrete supercells were possible amid steep lapse rates. Tropical Storm Edouard’s outer bands added a localized 2% tornado threat along the southeast Texas/southwest Louisiana coast through modest destabilization and enhanced low-level hodographs. These official NWS products, updated throughout the day, anchored trader assessments of city-specific risk ahead of any post-event verification data.