Low, lingering smoke from a campfire indicates ________ pressure and _______ air and may indicate an approaching rain shower.

Low, lingering smoke from a campfire is associated with lowering pressure and unstable air. When the atmospheric pressure is decreasing, it often indicates that a storm system is approaching. Unstable air means that the air currents are more chaotic, which can lead to the development of clouds and precipitation. This condition often leads to changes in weather, such as an approaching rain shower.

In contrast, stable air would allow smoke to rise straight up and disperse more quickly, while high pressure is usually associated with good weather and would not typically result in low-lying smoke. Therefore, the combined indication of lowering pressure and unstable air supports the possibility of inclement weather developing, such as rain. This understanding is critical for someone in outdoor guiding, as it can influence safety and planning for activities in natural settings.