Upper-air Weather Chart

Weather maps that are produced for the portion of the atmosphere above the lower troposphere, generally at and above 850 mb. Isolines on these maps usually represent the heights of a constant pressure surface, such as the 500 mb surface.

Weather maps that are produced for the portion of the atmosphere above the lower troposphere, generally at and above 850 millibars. Isolines on these maps usually represent the heights of a constant pressure surface, such as the 500 millibars surface.