"Unexpected turbulence" refers to an unpredictable and sudden disturbance or disruption that can happen in various areas of life, such as in plans, events, or situations, causing unexpected difficulty or challenges. Full definition
They have also made the first map of the velocities of material in the atmosphere of a star other than the Sun, revealing unexpected turbulence in Antares's huge extended atmosphere. (astronomynow.com)
They also made a map of the velocities of material in the atmosphere of Antares, revealing unexpected turbulence. (daviddarling.info)
The FAA also says babies in car seats approved for flights are safer than lap babies during unexpected turbulence. (blog.guguguru.com)