Skew-T log-P diagram

In 1947, N. Herlofson proposed a modification to the emagram that allows straight, horizontal isobars and provides for a large angle between isotherms and dry adiabats, similar to that in the tephigram.

This made the diagram useful for analysis techniques that were then being adopted by the United States Air Force.

Plotting a hypothetical set of measurements with constant temperature for all altitudes would result in a line angled 45° to the right.

The isopleths on the diagram can then be used to simplify many tedious calculations involved, which were previously performed by hand or not at all.

The diagrams are widely used by glider pilots to forecast the strength of thermals and the height of the base of the associated cumulus clouds.