Low pressure systems
A: A low pressure area, or a low for short, is a region where the atmospheric pressure is lower than that of a surrounding area, said Brent McRoberts of Texas A&M University.
“A low pressure system develops when warm and moist air rises from the Earth’s surface,” he explained. “Air near the center of this mass is usually unstable. As the warm and humid air rises, it may become thick enough to produce rain or even snow.”
Q: So does a low pressure system mean bad weather?
A: Generally, the answer is yes, McRoberts said.
“Areas of low pressure tend to be very cloudy and often contain rain or thunderstorms. Likewise, areas of high pressure are usually associated with clear and sunny weather,” he added. “High pressure is the direct opposite of a low pressure system. It is an area where the air’s pressure is higher than the pressure in the surrounding area. So usually, high pressure means good weather and low pressure means rainy or stormy weather.”