What weather phenomena are included in the "present weather" section of a METAR?

The "present weather" section of a METAR, which is an aviation weather report, includes phenomena that are currently occurring at the time of observation. This section is crucial for pilots and other aviation personnel as it provides immediate information on significant weather conditions that might affect flight operations.

The correct answer highlights that dust, squall lines, and tornado activity are indeed classified as present weather phenomena. These occurrences can have an immediate and direct impact on flying conditions. For instance, dust storms can reduce visibility, squall lines can bring rapid changes in wind and precipitation, and tornado activity is critical for safety assessment during flight operations. Thus, this option accurately reflects the types of weather phenomena reported in the METAR's present weather section.

In contrast, precipitation data alone does not encompass the full range of present weather; only focusing on precipitation would ignore other critical phenomena like severe weather events. Averages of conditions over time do not apply as METAR reports current conditions rather than historical averages, and previous weather reports are also not included in the present weather section, as METAR is focused on real-time observations.