Skew-T Procedure
The determination of the MCL first requires estimation of the height of the top of the mixed layer. This is done subjectively using local forecasting methods.
Once the top of the mixed layer is estimated, one must determine the mean dry adiabat and the mean mixing ratio of the mixed layer.
The mean dry adiabat is determined from the sounding T curve by the equal-area method shown in the skew-T.
The mean mixing ratio is determined from the sounding Td curve by the equal-area method shown in the skew-T.
The MCL lies at the level of intersection of the mean saturation mixing-ratio line with the mean dry adiabat within the mixed layer. If these two lines intersect above the mixed layer, then the mixed air is too dry to reach saturation by the mixing process and no MCL exists.
In this example, there is an MCL at 830 hPa, since it lies below the top of the mixed layer at 780 hPa.