When analyzing weather charts, what is indicated by a marked trough?

A marked trough on weather charts indicates a significant area of low pressure, which often corresponds with unsettled weather conditions. In meteorology, troughs are associated with rising air, which leads to cloud formation and can result in precipitation. The presence of a trough suggests that moisture can be lifted into the atmosphere, increasing the likelihood of rain or storms. This contrasts with a ridge, which typically signifies high pressure, stable air, and clearer conditions.

The correlation between troughs and low pressure is crucial in forecasting. Areas where troughs are located are often where significant weather changes occur, making them important for predicting potential rain, thunderstorms, and other forms of precipitation.