I tend to lean this direction as well. The weather wasn't all that remarkable. In fact, it was on the downwind side of an upper level ridge which normally is fairly tranquil. In the transcript that I provided after reviewing the ATC conversation with the pilot, there was no mention of an encounter with weather. The pilot was very tight-lipped. I would have thought that a turbulence encounter may sound more like, "yeah, we hit some rough air and one of the pax received a laceration and needs immediate medical attention." There was no pilot weather report filed for severe turbulence. However, the NTSB's tweet initially mentioned turbulence.