Crests of standing mountain waves may be marked by which type of cloud?

Standing lenticular clouds are typically associated with the crests of standing mountain waves. These clouds form when stable air flows over mountain ranges, creating a wave-like pattern in the atmosphere. As the air rises and cools at the crest of the wave, it can condense into visible clouds, shaping them into smooth, lens-like formations that can appear stationary, even as the wind flows continuously.

The appearance of standing lenticular clouds indicates the presence of mountain wave activity, which can be crucial for pilots to recognize, as it often suggests turbulent conditions in the surrounding air. These clouds may also serve as a visual cue to potential downdrafts and turbulence that can exist in the vicinity.

Other types of clouds mentioned, such as low stratus clouds, thunderstorm clouds, and cirrus clouds, typically do not form in association with standing mountain waves in the same way. Low stratus clouds generally represent uniform, flat layers of cloud at low altitudes, while thunderstorm clouds (cumulonimbus) are associated with convective activity rather than stable air over mountains. Cirrus clouds are high-altitude clouds that indicate weather systems but are not indicative of mountain wave phenomena.