Final answer:
Tower visibility refers to the visibility from an airport control tower and can differ from prevailing surface visibility and PIREPs. Weather conditions and differences in atmospheric pressure greatly affect visibility, which is crucial for flight safety.
Step-by-step explanation:
The report of tower visibility usually refers to the observable distance from a particular vantage point, typically an airport control tower, and is related to the current weather conditions affecting that area. This can differ from prevailing surface visibility, which is a measure of the transparency of the air at ground level over a wide area, and may not be as localized as the view from the tower.
Aircraft pilots often provide PIREPs, which are Pilot Reports detailing actual weather conditions encountered during flight. These reports can include information about clear sections of sky, turbulence, or wind shear, and can be critical for understanding weather conditions that are not visible or reported from the ground.
Surface visibility is heavily influenced by weather conditions such as clouds, wind, rain, and pollution. A large difference in pressure between two areas can signal the potential for strong winds or storms, and under some conditions, this can lead to severe weather events like tornadoes. Aircraft may be grounded, and other safety measures taken when weather conditions severely limit visibility.