A trough is an elongated area of low pressure that can stretch for hundreds of miles. When observing an upper-level jet ...

Trough: An elongated area of low air pressure, often several hundred miles in length, containing no low pressure center and therefore no closed isobars. The term is used to distinguish from a low ...

Trough: An elongated U-shaped area of low air pressure, often several hundred miles in length, containing no low pressure center and therefore no closed isobars. Skip to content.

A trough is an elongated area of low pressure that can stretch for hundreds of miles. When observing an upper-level jet diagram, troughs appear as a “dip” or a “U-shape”.