Which Surface is the Surface Strikes Again

or

There is a difference.  The Cond. arrow show that the base of a cloud expands as long as it is fed by moisture.  The bottom shows the path of moisture if the cloud base is fully saturated.  Fully saturated, there is no path for surface moisture through the condensation layer.  There would need to be some space where surface moisture has a path around the condensation layer if it is to feed the cloud.

The moist air arrows represent the available atmospheric moisture and the dry air plus the arrow from the surface, the induced air flow.  With cold dry air descending (warming) and warm moist air rising (cooling), the rising air is limited by its moisture content and the temperature of condensation at the level of moisture.  If the surface moist air is moist enough, then condensation would be at or below the average temperature of the cloud base condensation layer.  That would produce the larger pressure differential causing the cloud to build.

If the surface moisture is low, then the surface air would saturate at a lower temperature reducing the pressure differential and the cloud would not build or have less building depending on the new condensation temperature.

Both the actual surface and the cloud condensation surface would need to be considered if the condition of the cloud system is to be predicted.  If the condensation surface grows very large, the cloud would pull apart.  If the surface moisture is below a critical level, the cloud would not build.

What is the critical dimensions of the condensation base and the surface moisture/temperature?