Last week, an enormous saucer-shaped cloud appeared over Japan. Was it an alien ship in disguise, or perhaps an enormous publicity stunt by a weather-controlling hat company? No, it’s just a lenticular cloud, and a reminder that weather is awesome.
Though rare, meteorologists have a pretty good idea of how these saucer-shaped clouds come into existence. From Wikipedia:
Where stable moist air flows over a mountain or a range of mountains, a series of large-scale standing waves may form on the downwind side. If the temperature at the crest of the wave drops to the dew point, moisture in the air may condense to form lenticular clouds. As the moist air moves back down into the trough of the wave, the cloud may evaporate back into vapor.
Though I am hardly qualified to predict the weather, this sounds like the moist, cloud-making air is getting shoved upward where it quickly condenses into clouds. As the air flows upward, the clouds appear to “stack” on top of each other creating the unique formation.
The conditions were certainly set for a lenticular cloud over Japan last week when the cloud appeared. A typhoon had just blown through the region — no doubt bringing with it some moist air. And the proximity to Japan’s famous Mt. Fuji is probably no coincidence, either. Wikipedia notes that while lenticular clouds can form over mountains, they can also form downwind of mountains as the air in the standing wave peaks again.
Now, you could accept scientist’s completely logical explanation, or you could opt for the far more interesting (and crazy) theory that lenticular clouds are clever camouflage for UFOs. Because a race of space beings capable of building interstellar craft and disguising them as clouds didn’t consider using a less noticeable shape. Obvi.
(via Bad Astronomy)
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