MADISON, Wis. – Both are ominous looking clouds that are sometimes present with thunderstorms and are often confused for each other. Let’s take a look at a shelf cloud, a wall cloud and discuss how they are different from one another and how you can spot the difference.
Let’s start off with a shelf cloud. An ominous looking cloud, a shelf cloud is a type arcus cloud; a type of cloud that usually forms lower in the atmosphere, fairly horizontal and is usually part of a cumulonimbus cloud. The other type of arcus cloud is called a roll cloud which can form without a thunderstorms or cumulonimbus cloud nearby.
Formed by rain cooled air rushing out ahead of the center of the storm, the colder air forces warmer moist air up into the atmosphere. Sometimes stretching miles, shelf clouds indicate that strong wind is likely to follow the passing of the ominous looking cloud…