Clik here to view.
ASK THE METEOROLOGIST
“Why does rain not always bring lightning and thunder?”
Ainsley, St. Mary’s School
The answer to this question lies in the height of the clouds that produce the rain. When showers move through, they fall from shorter, more shallow clouds. That means the separation of charges that causes lightning in the first place is not large. More simply, there is not a large distance between the pool of negative charges normally found at the base of the cloud from the positive charges that are located in the top of the cloud.
When we see tall, towering cumulus, or cumulonimbus clouds, there is a great distance separating the positive charges in the clouds tops from the negative charged pooled at the base of the cloud. When this happens, there is more of a need for the atmosphere to “discharge” that built up energy – in the form of lightning. So, when clouds are shorter, we usually see just rain without the lightning and thunder.
Chief Meteorologist Kate McKenna
