How is a wind and temperature aloft forecasted at FL390 encoded in the FD?

The correct encoding for a wind and temperature aloft forecast at Flight Level 390 (FL390) is represented as 789951. In this format, the first three digits (789) indicate the wind direction and speed, with the first digit (7) specifying the wind is from the 360° sector, and the additional digits indicating the wind direction and speed in knots. The remaining two digits (51) represent the temperature at that altitude, which is 51 degrees Celsius.

This coding uses a standard format for upper-level wind and temperature forecasts, where the first digit provides the wind level, the next two digits provide wind speed, and the final two digits represent the temperature. Understanding this system is crucial for interpreting weather data for flight planning and safety.