PIREP

PIREP, short for Pilot Report, is a weather observation provided by pilots during or after a flight. It describes actual atmospheric conditions encountered in flight and is intended to supplement weather observations from ground stations, radar, satellites, and forecast models. PIREPs can cover a range of phenomena and may include information on turbulence, icing, visibility, cloud cover, wind at altitude, and other conditions that affect flight safety and operations.

Typical content of a PIREP includes the time and location of the report, the altitude or flight level, and the observed weather phenomena. Pilots may report turbulence intensity, icing conditions, wind shear, and obstructions to visibility, among other factors. The report aims to convey real-time or near-real-time conditions rather than forecast expectations.

Reporting mechanisms and codes: PIREPs can be submitted as routine reports or urgent reports when weather conditions pose a significant hazard. Routine PIREPs may be designated UA, while urgent reports are marked UUA in some systems. Reports are transmitted to air traffic control, airline operations centers, or meteorological agencies, and are distributed through weather data networks and data-link systems.

Uses and significance: PIREPs are used by meteorologists to verify and improve weather analyses and forecasts, including turbulence and icing forecasts. They also enhance situational awareness for pilots and controllers, contributing to safer flight planning and operations, especially near storms, fronts, or mountainous regions.

Limitations: PIREPs are subjective observations and depend on the pilot’s perspective, experience, and equipment. Location and timing may be imprecise, and reports vary in level of detail. Despite limitations, they remain a critical source of real-world weather data in aviation.