- Will Chicago, IL face tornado risk on August 26?3¢
- Will Houston, TX face tornado risk on August 26?1¢
- Will San Antonio, TX face tornado risk on August 26?5¢
- Will Dallas, TX face tornado risk on August 26?3¢
- Will Austin, TX face tornado risk on August 26?4¢
- Will Fort Worth, TX face tornado risk on August 26?4¢
- Will Columbus, OH face tornado risk on August 26?3¢
- Will Charlotte, NC face tornado risk on August 26?3¢
- Will Indianapolis, IN face tornado risk on August 26?52¢
- Will Denver, CO face tornado risk on August 26?2¢
- Will Nashville, TN face tornado risk on August 26?3¢
- Will Oklahoma City, OK face tornado risk on August 26?4¢
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 August 26, 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 outlook places a 2% tornado probability across portions of the southern Great Lakes and Midwest, highlighting cities such as Detroit, Indianapolis, Toledo, and Fort Wayne, where a mid-level shortwave and surface cold front are driving moderate instability and 25–35 kt deep-layer shear this afternoon. Low-level winds remain veered with limited hodograph curvature, keeping tornado potential low and favoring damaging winds or large hail instead. Official NHC and local NWS discussions note that any embedded supercells would require storm-scale interactions for brief rotation, consistent with climatological patterns for late-August frontal passages. Updated model runs and 19–22Z convective initiation timing represent the next key data points that could refine city-level risk areas before the period ends at 12Z August 27.