EF1 tornado in Osage County, Oklahoma

This is the first segment of a two segment tornado. In Osage County, the tornado snapped or uprooted a number of hardwood trees. Large tree limbs were snapped, one of which fell onto the roof of a home. Based on this damage, estimated maximum wind in the tornado was 100 to 110 mph. It was photographed by a number of storm spotters and storm chasers. This tornado continued into Washington County, Oklahoma.

Severe thunderstorms developed along a nearly stationary frontal boundary over central Oklahoma during the early afternoon hours of the 20th. Very unstable air combined with strong low-level and deep-layer shear resulted in long-lived supercells forming over central Oklahoma and moving eastward into eastern Oklahoma. Several tornadoes occurred from these storms across Osage, Washington, and Nowata Counties. The storms organized into bow echos and line segments over eastern Oklahoma, from which several other tornadoes developed during the early evening hours across Ottawa, Adair, and Le Flore Counties. Damaging wind and large hail was also widespread across the region from these storms.