Plain English Meaning

It is the label inside a pilot weather report that says: 'Here comes the turbulence information.' Whatever follows tells you how rough the air was.

Full Definition

In a PIREP (Pilot Report), /TB is the field identifier introducing turbulence information reported by the pilot. The letters following /TB describe the intensity and type of turbulence encountered (for example, /TB LGT, /TB MOD-SEV CHOP).

Context Anchor

Seen when reading or decoding pilot weather reports, especially when checking ride conditions along a route or at a planned altitude.

Derivation

The slash separates fields in a PIREP. 'TB' is shorthand for Turbulence. use a fixed sequence of slash-coded fields so any can straight to the part they need.