What does "OCNL" mean in the context of TAF reports?

In the context of TAF reports, "OCNL" stands for "occasional." This term is used to describe weather phenomena that occur intermittently within a specified period of time, rather than continuously. For instance, if the TAF indicates "OCNL showers," it suggests that there will be sporadic or infrequent rainfall at the aerodrome, rather than steady or persistent precipitation.

This understanding is important for flight planning and operations, as it helps pilots and air traffic controllers anticipate changes in weather conditions that might affect visibility, cloud cover, or precipitation. The use of "OCNL" allows for more nuanced weather forecasting, which is crucial for making informed operational decisions.

The other choices, while they present plausible weather phenomena, do not correctly capture the meaning of "OCNL." The term does not specifically denote ongoing events, cloud formations, or original weather patterns. Instead, it emphasizes the sporadic nature of certain weather occurrences relevant to aviation operations.