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Mammatus Clouds over Nebraska

April 15, 2014

Your birthday marks the moment a small planet circling a modest star gained another witness to its wonders.

Mammatus Clouds over Nebraska

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APOD published April 15, 2014. Credit: Jorn Olsen Photography. A publication-date match, not a photo taken on your date. Independent of NASA.

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Mammatus Clouds over Nebraska

Original APOD · April 15, 2014

When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such pockets may occur in turbulent air near a thunderstorm. Resulting mammatus clouds can appear especially dramatic if sunlit from the side. The mammatus clouds pictured above were photographed over Hastings, Nebraska during 2004 June.

Image credit: Jorn Olsen Photography

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