Aeronautical Terms beginning with O

Occluded Front

The front formed by a cold front overtaking a warm front and lifting the warm air above the Earth’s surface. An occlusion (or frontal occlusion) forms when an air mass is trapped between two colder air masses and is forced to higher and higher levels.

One-Minute Weather

The most recent 1-minute update weather broadcast based on ASOS/AWOS measurements and available to a pilot from an uncontrolled airport ASOS/AWOS.

Orographic Cloud

A cloud that usually results from air flowing upslope from terrain and being cooled adiabatically.

Outside Air Temperature (OAT)

The measured or indicated air temperature outside the aircraft that is uncorrected.