- Will Chicago, IL face tornado risk on September 3?<1¢
- Will Houston, TX face tornado risk on September 3?<1¢
- Will San Antonio, TX face tornado risk on September 3?<1¢
- Will Dallas, TX face tornado risk on September 3?<1¢
- Will Austin, TX face tornado risk on September 3?<1¢
- Will Fort Worth, TX face tornado risk on September 3?<1¢
- Will Columbus, OH face tornado risk on September 3?<1¢
- Will Charlotte, NC face tornado risk on September 3?<1¢
- Will Indianapolis, IN face tornado risk on September 3?<1¢
- Will Denver, CO face tornado risk on September 3?<1¢
- Will Nashville, TN face tornado risk on September 3?<1¢
- Will Oklahoma City, OK face tornado risk on September 3?<1¢
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 3, 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.
SPC Day 1 convective outlooks issued September 3, 2026, placed a Slight Risk of severe thunderstorms across the southern Great Lakes, Upper Midwest, and Mid-Atlantic, with an Enhanced Risk focused on eastern Ohio and western Pennsylvania. Tornado probabilities reached 2% across a broad corridor including Detroit, Milwaukee, Cleveland, and Pittsburgh, rising to 5% near Fargo and Moorhead in the northern Plains where stronger instability and shear supported isolated supercells. An MCS tracked through northern Ohio that evening, producing measured wind gusts of 60–62 mph near Cleveland but limited confirmed tornado activity. NOAA/NWS Storm Prediction Center guidance emphasized damaging winds and hail as primary hazards, with tornado risk remaining conditional on discrete supercell development amid moderate deep-layer shear. Official verification reports and any late-day watches or warnings issued by local NWS offices will determine final market resolution for affected cities.