Norman, OK hail storm history

What the National Weather Service wrote

As strong low-level flow increased in the vicinity of a warm front (across the Red River Valley), widespread strong to severe thunderstorm development occurred across the southern half of the forecast area during the early morning of the 12th. Given a mesoscale environment characterized by high magnitudes of elevated instability and deep-layer wind shear, the strongest storms produced reports of large to very large hail. This included reports of baseball-sized hail near the town of Elgin in northeast Comanche County. A few reports of thunderstorm wind were also received across southeast Oklahoma as storms grew upscale. By the afternoon, sufficient (elevated) instability and wind shear remained such that additional storm development, in the vicinity of a stationary boundary across north Texas, produced reports of sub-severe hail.