So just what is a shelf cloud?

So just what is a shelf cloud?

. - MYRTLE BEACH, SC (WMBF)  Strong to severe storms the past two days have provided some dramatic skies and several stunning examples of shelf clouds. 

So, just how are these shelf clouds formed?

As a thunderstorm develops and matures, heavy rain begins to fall from the clouds.  As the rain falls, it cools the air and drags down cooler air from the upper layers of the atmosphere.  As the cool, moist air hits the surface of the earth it begins to
spread out along the leading edge of the thunderstorm.  As the cooler air rushes out ahead of the storm, warm and moist air is forced upwards very quickly.  This rising, warm air quickly cools and the rising air saturates and develops into a cloud structures.
 This is what develops the shelf cloud.  

Shelf clouds do not always mean severe weather but can be associated with severe storms and very strong winds at times.  As a shelf cloud passes overhead, you'll often notice an increase in winds and d rop in temperatures.  

Sometimes, the shelf cloud can outrun the parent thunderstorm by a long distance - occasionally up to 50 miles or so. 

All shelf clouds are different.  Some look more like a collar of clouds surrounding a thunderstorm.  Others are sloped and smooth.  Sometimes, shelf clouds have a ragged and turbulent appearance especially when viewed from underneath.