Scud clouds in State College, Pennsylvania, on May 30, 2012. (AccuWeather/Jesse Ferrell) Often called "scary-looking clouds," by meteorologists because viewers reported them as funnel clouds or ...

Supercells are quite literally spinning thunderstorms. The more instability, or storm fuel — derived from warm, humid air — the taller a storm cloud can grow. Eventually, the cloud will reach ...

These could be low-topped supercells. They won't look impressive ... Jonathan says there may be some scary-looking clouds. He added that he would not be surprised there were a couple of funnels ...

LP supercells often produce tornadoes and large hail. The classic, textbook supercell looks much like the figure above. The storm will have a flat updraft base and potentially a wall cloud ...

Wall, scud, shelf and other scary looking clouds There’s an example of a scud and some other scary-looking clouds (mostly just cumulonimbus) from Friday the 13th below: ...

This rotating cloud structure is crucial; it’s here that atmospheric spin intensifies and tornadoes can potentially develop. Interestingly, only about 30% of supercells produce tornadoes ...

But not all scary, suspicious clouds looming beneath a storm are an indication that a tornado is imminent. A boiling summertime sky can feature more than a dozen types of clouds floating at all ...

And though only about 20 percent of supercells generate tornadoes ... Credit: John Sirlin Alamy Stock Photo Tornado funnel and debris cloud under a supercell in McCook, Neb.