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Timelapse: Lenticular clouds last for hours over Flagstaff mountains

Video released by the National Weather Service shows a lenticular cloud over Flagstaff, Ariz. This type of lens-shaped cloud normally develops on the downwind side of a mountain or mountain range. (Video: NWS Flagstaff/Twitter)

Beautiful, long-lasting lenticular clouds formed over the mountains of Flagstaff, Ariz., on Thursday afternoon and persisted until sunset. The clouds were captured in a timelapse video by the National Weather Service.

Another exceptional case of these pancake-shaped clouds formed over Cape Town, South Africa, in November. The Capital Weather Gang’s Kathryn Prociv explained how they form:

I’m happy to report that they were neither spaceships nor pancakes, but lenticular clouds, or altocumulus standing lenticularis, which is Latin for “lens-shaped.”
Lenticular clouds form in stable environments with strong winds aloft, where moist but stable air flows over a mountain creating standing gravity waves on the downwind (or lee) side. Generally, the mountain range must be oriented perpendicular to the prevailing winds in order for this clouds to form. If the air temperature cools enough to condense the water vapor in it, a lenticular cloud may appear.

If you watch closely in the video above, you can also see the morning weather balloon launch around the 2-second mark.

More cool clouds:

The top 5 weirdest cloud types

Surf’s up for snow lovers: Incomparable Kelvin Helmholtz clouds in Breckenridge

Flying saucer clouds baffle onlookers in Cape Town

Super-rare flying saucer clouds float over Blue Ridge

Lenticulars hover over Charlottesville, Va.