Final answer:
Low pressure generally indicates that there is less atmospheric pressure at the surface compared to surrounding areas, leading to the uplift of moist air, cloud formation, and commonly stormy weather, making the statement true.
Step-by-step explanation:
The statement that low pressure means the air weighs less and indicates stormy weather is generally true. In meteorology, when there is a low-pressure system, it implies the atmospheric pressure at the earth's surface is lower than its surroundings. This low pressure allows moist air to rise and condense, forming clouds, and can lead to the development of storms and other weather events such as tornadoes. The difference in pressure between high and low-pressure areas causes winds to form, and when this difference is significant, the winds can become strong, potentially leading to severe weather conditions like storms or tornadoes.
Therefore, when meteorologists observe a low-pressure system on weather maps, where isobars indicate regions of varying pressure, they often predict stormy weather. This is because low-pressure environments are conducive to the upward movement of air that leads to the formation of clouds and precipitation.