What does +FC indicate on a METAR?

The indication of +FC in a METAR refers to "funnel cloud," which can be associated with strong weather phenomena. Specifically, +FC signifies the potential for tornadoes, as funnel clouds are often the precursors to tornado activity. This marker helps pilots and meteorologists assess severe weather conditions, especially when determining air traffic safety and flight operations.

The other options, while related to severe weather, do not apply to the +FC designation. For instance, waterspouts are typically indicated differently, and dust devils do not have a specific indicator in METAR reports. Severe thunderstorms might be represented by different symbols or descriptors that indicate thunderstorms' intensity but not necessarily funnel clouds. This understanding is crucial for recognizing severe weather threats in aviation.