When are tower visibility entries transmitted in the METAR observation?

In METAR observations, tower visibility entries are transmitted when the tower visibility is less than the surface visibility. This is important for safety as it provides pilots with critical information about conditions that may differ significantly between the airport area and the surrounding airspace.

In this case, surface visibility is reported as 3 statute miles, and tower visibility is 2 statute miles. This situation meets the criteria for reporting both surface visibility and tower visibility because tower visibility is less than surface visibility. It ensures that the observation accurately reflects conditions that could affect pilot operations and decisions.

The other scenarios indicate instances where either tower visibility is equal to or greater than surface visibility or does not meet the criteria for transmission based on the defined requirements. Hence, only the scenario where tower visibility is less than surface visibility appropriately fits the guidelines for including these entries in the METAR observation.