Hail in Osage County, Oklahoma

Severe thunderstorms developed across northeastern Oklahoma during the evening of the 26th, near a warm front as an upper level disturbance approached the region from the west. The atmosphere across eastern Oklahoma became very unstable during the afternoon and early evening and the deep-layer wind shear was strong with the approach of the upper level disturbance. Some of the thunderstorms were able to develop into supercells due to the favorable combination of instability and wind shear. Several tornadoes and large hail up to quarter size occurred with the strongest thunderstorms.