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The skew-T/log-P diagram is used to plot vertical profiles through the atmosphere. It has been used for many decades to assess a variety of meteorological conditions, most notably atmospheric stability.

Data for sounding plots come from numerous sources such as radiosondes, dropsondes, pibals, aircraft, NWP model output, and satellite sounders. To decode data formats for a particular data source, one should refer to the appropriate reference manual. While most soundings today are plotted electronically, the instructions in this module are also relevant for manual plotting on a skew-T diagram.

Since pressure decreases logarithmically with increasing height in the atmosphere, the diagram has lines of constant pressure (isobars) spaced logarithmically. This leads to the skewed appearance of lines of constant temperature (isotherms). Thus the diagram is called a skew-T/log-P diagram and is frequently referenced (including hereafter in this module) as a skew-T diagram.

This section describes the various sets of lines and data that appear on the skew-T/log-P diagram.

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