How would visibility dropping to 1/4SM due to fog between 1000 and 1300 UTC be reported in the TAF?

The correct reporting of reduced visibility due to fog in a Terminal Aerodrome Forecast (TAF) should follow the established format for indicating temporary weather conditions. In this context, the visibility of 1/4 statute mile due to fog should be clearly stated alongside its effect on visibility.

When fog (FG) impacts visibility, it is essential to state both the visibility measurement and the weather phenomenon. This is original and consistent with TAF reporting standards. The format typically used is to specify the visibility, followed by the weather phenomenon affecting that visibility.

In option A, the format starts with the time frame during which the temporary condition is expected, then specifies the visibility as 1/4 SM, followed by the weather phenomenon (FG for fog). This arrangement clearly communicates the expected drop in visibility due to fog within the specified time frame, which is essential for pilots and air traffic controllers to make informed operational decisions.

In contrast, other options either misplace the elements or do not correctly distinguish between visibility and the weather phenomenon, which could lead to misunderstandings regarding the forecasted conditions. Proper understanding and interpretation of TAF reports is critical for safety and operational planning in aviation contexts.