When tower visibility is recorded in column 7b, what values are needed?

When tower visibility is recorded in column 7b, the requirement is to provide specific visibility values that differentiate between surface visibility and tower visibility. In this context, surface visibility indicates the distance at which objects can be distinctly seen at ground level, while tower visibility is defined as visibility in the vicinity of the control tower.

The notation where SFC VIS = 3 and TWR VIS = 2 is critical because it clearly separates the two types of visibility measurements. This distinction helps airport personnel and meteorologists understand the current weather conditions and how they might affect flight operations. In situations where visibility varies significantly between the surface and the tower, documenting both with specific values aids in accurate reporting and decision-making.

This option focuses explicitly on the requirement that both surface and tower visibility need to be recognized and recorded, emphasizing their importance for accurate weather observations and ensuring safety in aviation operations.