In aviation, what does the weather term PO refer to?

The term PO in aviation specifically refers to "Dust/Sand Whirls." This term is used to describe small, rotating columns of air that pick up dust or sand from the ground and can create localized, turbulent conditions that could impact flight operations. Understanding this phenomenon is crucial for pilots and drone operators because it can affect visibility and aircraft performance, especially when operating in arid or desert environments where such conditions are more prevalent.

The other options, while related to weather, do not accurately reflect the meaning of PO in this context. Poor Visibility refers to conditions where visibility is significantly reduced due to various factors like fog or heavy rain. Polluted Air generally encompasses broader air quality concerns that do not tie directly to the specific phenomenon of dust or sand whirlwinds. Lastly, Precipitation Overhead would concern general weather conditions related to rain or snow but does not relate to the specific air columns indicated by the term PO.