What is a trough in meteorological terms?

In meteorology, a trough refers specifically to a line of low pressure. This is a significant feature in weather patterns, typically associated with cloudy and rainy weather. Troughs are often connected to the movement of air masses and can influence the development of storms. The presence of a trough can create instability in the atmosphere, allowing for rising air, which can lead to precipitation and changes in weather conditions.

Unlike a line of high pressure, which is generally associated with clear skies and fair weather, a trough signifies areas where air is descending and leads to fewer stability in the atmosphere. Also, while a trough can be involved in storm development, it is not classified as a type of storm itself, nor is it a weather front, which describes a boundary between two different air masses rather than a specific atmospheric feature like a trough does. This is why identifying a trough as a line of low pressure is vital for understanding how it affects weather systems.