Learn how an air mass thunderstorm is different from other types of storms.
Understand the different stages in their development and the process of formation.
What Is an Air Mass Thunderstorm?
Have you ever experienced a perfect summer day, when suddenly in the late afternoon, the sky gets dark out of nowhere? Before you know it, a cloud forms and a storm develops. It starts pouring rain and flashing lightning, but only a few minutes later the rain turns to drizzle. Soon after that, the sky is completely clear again.
This is a common occurrence, and it’s a special type of storm. It’s called an air mass thunderstorm, and it is a non-severe storm that forms where moist and unstable conditions exist in the atmosphere.Air mass thunderstorms are considered garden variety, or ordinary, and there are many things about them that are different from other storms. They are associated with warm, moist, unstable air masses, hence the name. They are also considered to be single-cell storms. That just means that they are isolated, or they are just one storm rather than a whole line of thunderstorms.
The air mass thunderstorm is usually caused by solar radiation or the heating of the earth by the sun. This is why they are likely to happen in the late afternoon when we have the hottest temperatures of the day. The result is a storm that is weak rather than severe. It usually has a brief period of heavy rain, some lightning, and possibly small hail. They also move slowly and last only an hour or less. Because they tend to pop up suddenly, they are also hard to forecast. They are most common in the tropics and middle latitudes in the summer.
For example, they are extremely common in Florida and other Gulf Coast states.
The Life Cycle of Air Mass Thunderstorm Development
So, how does an air mass thunderstorm develop? There are three stages to the life cycle of an air mass thunderstorm. But first, there are a few conditions that must be in place for the process to begin. There needs to be vertical air motion, humidity, and instability. In the case of an air mass thunderstorm, it usually starts due to the heating of the ground by the sun.Since heat rises, this begins upward vertical air motion.
The heating and vertical motion cause an updraft of air that begins the storm’s formation. The first stage is called the cumulus stage. Air rises in updrafts above the freezing level in the atmosphere. The water droplets in the cloud freeze and begin to fall, creating a downdraft.The air and droplets leave the bottom of the storm as heavy precipitation, and this begins the mature stage of the thunderstorm. During this stage, both updrafts and downdrafts occur, and the storm continues to grow. This is when the storm is most active – when the rain, wind, hail, lightning, and thunder may occur.
Eventually, the updraft stops and only the downdraft remains. This is when the final stage, the dissipating stage, begins. The storm continues to lighten up until it finally ends.
To review, an air mass thunderstorm is a special kind of storm that occurs when the air is humid, warm, and unstable. They are single-cell, or isolated, storms that are caused by the heating of the ground from solar radiation.
This is why they tend to happen during the hottest part of the day. These types of storms are usually weak and only last a brief period of time. They also move quite slowly and are hard to forecast. Air mass thunderstorms develop in three distinct stages.
The first is the cumulus stage where air starts to rise and forms a cloud. The second is the mature stage where precipitation falls, and a downdraft occurs. This is the most active stage when lightning, thunder, and hail may occur. Eventually, the updraft stops, and the storm is in the final, dissipating stage until it ends.