They can be used to find areas of low or high pressure over a broad area (like the U.S.), and they can tell us how intense the system may be. On weather maps, you may have noticed areas that have a large “L” or “H” over a region with lines circling around them. The “L” stands for low pressure.
The lines circling them are isobars. Generally the lowest pressure is where precipitation is most likely to fall, and high pressures are usually associated with clear and sunny conditions..
Isobars are lines of constant or equal pressure on a weather map..