Such storms are rarely severe and are a result of local atmospheric instability; hence the term "air mass thunderstorm". When such storms have a brief period of severe weather associated with them, it is known as a pulse severe storm.
These storms are infrequently intense and arise from localized atmospheric instability; therefore, they are referred to by this name. If these storms feature a short-lived episode of severe weather connected to them, it is called a pulse severe storm.