Which of the following is an example of significant weather that should prompt a PIREP?

The choice of severe turbulence or low visibility is a fitting example of significant weather that should prompt a Pilot Report (PIREP). PIREPs are essential for sharing crucial information about current weather phenomena that may impact flight safety and operations. Severe turbulence can significantly disrupt the aircraft's stability and passenger comfort, while low visibility can hinder navigation and approach procedures, posing risks during takeoff and landing.

These reports help other pilots and air traffic controllers to adjust their decision-making based on real-time weather conditions. On the other hand, smooth flight experiences, clear skies with no turbulence, and routine landing procedures do not indicate significant weather or conditions that would necessitate a PIREP. They represent typical, expected, and safe operational situations where no extraordinary weather phenomena are at play. Thus, they don’t contribute to the necessary ongoing awareness of dynamic atmospheric conditions critical for safe aviation operations.