Weather Education – Air Mass Thunderstorms

Air mass thunderstorms are found in marine time tropical air. In short they are also known as MT Thunderstorms.

Air mass thunderstorms represent what is known as the common three stage thunderstorm development. This means that an air mass thunderstorm goes through the stages of Cumulus which is represented by the updrafts only being present; secondly it moves into the mature stage where it has both updrafts and downdrafts; finally it goes into the dissipating stage where you see only the downdrafts.

Air mass thunderstorms are most common in the summer as they need very warm and moist air to form. They are most commonly found along the Gulf Coast region stretching from Texas all the way into the Carolina’s.  Air mass thunderstorms are also known for forming what is known as the land and sea breeze.  What happens here is during the day the land heats up faster than the water causing the warm air from the land to rise up and be replaced by the cooler air from the sea. This leads to the development of air mass thunderstorms during the day over the land.

These thunderstorms also need time to develop, which is why you will most often not see them on the coast itself, but rather about 5 miles inland from the coast.

At night the opposite occurs as the land cools faster than the water.  This means that the water now is warmer so the air is rising over the sea, which in return the cooler air from the land rushes over the water. At night we get what is known as the land breeze meaning the air is moving from land to water. Now the thunderstorms will form about 5 miles out over the open waters, rather than over land.

When looking at a weather map the best way to identify if you are going to see these type of thunderstorms during the day and night is to locate the sub-tropical high pressure and see where it is at. These thunderstorms are very common on the western side of the sub-tropical ridge.

Air mass thunderstorms are not known for their severe levels. This means that most air mass thunderstorms are nothing more than a heavy rain maker. It is very common to see places get well over 2 inches of rain just from one storm. These thunderstorms usually do not have the right conditions to form tornadoes, so the most common things to see with these storms are very strong winds and heavy rain.

Image Caption: An air mass thunderstorm forms. Credit: Joshua Kelly Meteorologist Joshua Kelly