Tuesday’s Ask Storm Team 11 question is: What is a pileus cloud? In the summertime, sometimes you’ll see a towering cumulonimbus cloud as a thunderstorm develops. It can reach 30,000 to even 50,000 feet high.
Occasionally, you’ll see what looks like a hat or halo on top of the cloud, called a pileus cloud. How does that happen?
First, you need warm air to rise very quickly and if you also have a thin layer of moist air in the upper levels of the atmosphere, you can get pileus clouds to form as the warm air punch through the moisture aloft.
The cap-like appearance comes as the wind flow above the clouds is horizontal.
It is often a sign of a rapidly developing thunderstorm that may even be strong or severe.
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