NTSB Factual Report

After receiving a forecast of turbulence from air traffic control (ATC), the flight crew briefed the flight attendants, informed the passengers via the public address system, and the seatbelt sign was illuminated. During descent for landing, the airplane encountered turbulence as the flight crew was maneuvering to avoid weather and radar returns. During the event, a flight attendant standing in the aft galley sustained a serious injury to his right ankle when he was lifted and dropped back to the floor. The remaining 149 passengers and crewmembers onboard were not injured. The flight crew declared an emergency and the airplane landed without further incident.

NTSB Probable Cause

Inadvertent encounter with convective turbulence while in descent.